linux/net/tipc/topsrv.c

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tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
/*
* net/tipc/server.c: TIPC server infrastructure
*
* Copyright (c) 2012-2013, Wind River Systems
* Copyright (c) 2017-2018, Ericsson AB
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the names of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* Alternatively, this software may be distributed under the terms of the
* GNU General Public License ("GPL") version 2 as published by the Free
* Software Foundation.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include "subscr.h"
#include "topsrv.h"
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
#include "core.h"
#include "socket.h"
#include "addr.h"
#include "msg.h"
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
#include <net/sock.h>
tipc: fix netns refcnt leak When the TIPC module is loaded, we launch a topology server in kernel space, which in its turn is creating TIPC sockets for communication with topology server users. Because both the socket's creator and provider reside in the same module, it is necessary that the TIPC module's reference count remains zero after the server is started and the socket created; otherwise it becomes impossible to perform "rmmod" even on an idle module. Currently, we achieve this by defining a separate "tipc_proto_kern" protocol struct, that is used only for kernel space socket allocations. This structure has the "owner" field set to NULL, which restricts the module reference count from being be bumped when sk_alloc() for local sockets is called. Furthermore, we have defined three kernel-specific functions, tipc_sock_create_local(), tipc_sock_release_local() and tipc_sock_accept_local(), to avoid the module counter being modified when module local sockets are created or deleted. This has worked well until we introduced name space support. However, after name space support was introduced, we have observed that a reference count leak occurs, because the netns counter is not decremented in tipc_sock_delete_local(). This commit remedies this problem. But instead of just modifying tipc_sock_delete_local(), we eliminate the whole parallel socket handling infrastructure, and start using the regular sk_create_kern(), kernel_accept() and sk_release_kernel() calls. Since those functions manipulate the module counter, we must now compensate for that by explicitly decrementing the counter after module local sockets are created, and increment it just before calling sk_release_kernel(). Fixes: a62fbccecd62 ("tipc: make subscriber server support net namespace") Signed-off-by: Ying Xue <ying.xue@windriver.com> Reviewed-by: Jon Maloy <jon.maloy@ericson.com> Reviewed-by: Erik Hugne <erik.hugne@ericsson.com> Reported-by: Cong Wang <cwang@twopensource.com> Tested-by: Erik Hugne <erik.hugne@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-18 01:32:57 +00:00
#include <linux/module.h>
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
/* Number of messages to send before rescheduling */
#define MAX_SEND_MSG_COUNT 25
#define MAX_RECV_MSG_COUNT 25
#define CF_CONNECTED 1
tipc: fix netns refcnt leak When the TIPC module is loaded, we launch a topology server in kernel space, which in its turn is creating TIPC sockets for communication with topology server users. Because both the socket's creator and provider reside in the same module, it is necessary that the TIPC module's reference count remains zero after the server is started and the socket created; otherwise it becomes impossible to perform "rmmod" even on an idle module. Currently, we achieve this by defining a separate "tipc_proto_kern" protocol struct, that is used only for kernel space socket allocations. This structure has the "owner" field set to NULL, which restricts the module reference count from being be bumped when sk_alloc() for local sockets is called. Furthermore, we have defined three kernel-specific functions, tipc_sock_create_local(), tipc_sock_release_local() and tipc_sock_accept_local(), to avoid the module counter being modified when module local sockets are created or deleted. This has worked well until we introduced name space support. However, after name space support was introduced, we have observed that a reference count leak occurs, because the netns counter is not decremented in tipc_sock_delete_local(). This commit remedies this problem. But instead of just modifying tipc_sock_delete_local(), we eliminate the whole parallel socket handling infrastructure, and start using the regular sk_create_kern(), kernel_accept() and sk_release_kernel() calls. Since those functions manipulate the module counter, we must now compensate for that by explicitly decrementing the counter after module local sockets are created, and increment it just before calling sk_release_kernel(). Fixes: a62fbccecd62 ("tipc: make subscriber server support net namespace") Signed-off-by: Ying Xue <ying.xue@windriver.com> Reviewed-by: Jon Maloy <jon.maloy@ericson.com> Reviewed-by: Erik Hugne <erik.hugne@ericsson.com> Reported-by: Cong Wang <cwang@twopensource.com> Tested-by: Erik Hugne <erik.hugne@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-18 01:32:57 +00:00
#define CF_SERVER 2
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
#define TIPC_SERVER_NAME_LEN 32
/**
* struct tipc_topsrv - TIPC server structure
* @conn_idr: identifier set of connection
* @idr_lock: protect the connection identifier set
* @idr_in_use: amount of allocated identifier entry
* @net: network namspace instance
* @awork: accept work item
* @rcv_wq: receive workqueue
* @send_wq: send workqueue
* @max_rcvbuf_size: maximum permitted receive message length
* @listener: topsrv listener socket
* @name: server name
*/
struct tipc_topsrv {
struct idr conn_idr;
spinlock_t idr_lock; /* for idr list */
int idr_in_use;
struct net *net;
struct work_struct awork;
struct workqueue_struct *rcv_wq;
struct workqueue_struct *send_wq;
int max_rcvbuf_size;
struct socket *listener;
char name[TIPC_SERVER_NAME_LEN];
};
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
/**
* struct tipc_conn - TIPC connection structure
* @kref: reference counter to connection object
* @conid: connection identifier
* @sock: socket handler associated with connection
* @flags: indicates connection state
* @server: pointer to connected server
tipc: eliminate struct tipc_subscriber It is unnecessary to keep two structures, struct tipc_conn and struct tipc_subscriber, with a one-to-one relationship and still with different life cycles. The fact that the two often run in different contexts, and still may access each other via direct pointers constitutes an additional hazard, something we have experienced at several occasions, and still see happening. We have identified at least two remaining problems that are easier to fix if we simplify the topology server data structure somewhat. - When there is a race between a subscription up/down event and a timeout event, it is fully possible that the former might be delivered after the latter, leading to confusion for the receiver. - The function tipc_subcrp_timeout() is executing in interrupt context, while the following call chain is at least theoretically possible: tipc_subscrp_timeout() tipc_subscrp_send_event() tipc_conn_sendmsg() conn_put() tipc_conn_kref_release() sock_release(sock) I.e., we end up calling a function that might try to sleep in interrupt context. To eliminate this, we need to ensure that the tipc_conn structure and the socket, as well as the subscription instances, only are deleted in work queue context, i.e., after the timeout event really has been sent out. We now remove this unnecessary complexity, by merging data and functionality of the subscriber structure into struct tipc_conn and the associated file server.c. We thereafter add a spinlock and a new 'inactive' state to the subscription structure. Using those, both problems described above can be easily solved. Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-02-15 09:40:44 +00:00
* @sub_list: lsit to all pertaing subscriptions
* @sub_lock: lock protecting the subscription list
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
* @rwork: receive work item
* @outqueue: pointer to first outbound message in queue
* @outqueue_lock: control access to the outqueue
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
* @swork: send work item
*/
struct tipc_conn {
struct kref kref;
int conid;
struct socket *sock;
unsigned long flags;
struct tipc_topsrv *server;
tipc: eliminate struct tipc_subscriber It is unnecessary to keep two structures, struct tipc_conn and struct tipc_subscriber, with a one-to-one relationship and still with different life cycles. The fact that the two often run in different contexts, and still may access each other via direct pointers constitutes an additional hazard, something we have experienced at several occasions, and still see happening. We have identified at least two remaining problems that are easier to fix if we simplify the topology server data structure somewhat. - When there is a race between a subscription up/down event and a timeout event, it is fully possible that the former might be delivered after the latter, leading to confusion for the receiver. - The function tipc_subcrp_timeout() is executing in interrupt context, while the following call chain is at least theoretically possible: tipc_subscrp_timeout() tipc_subscrp_send_event() tipc_conn_sendmsg() conn_put() tipc_conn_kref_release() sock_release(sock) I.e., we end up calling a function that might try to sleep in interrupt context. To eliminate this, we need to ensure that the tipc_conn structure and the socket, as well as the subscription instances, only are deleted in work queue context, i.e., after the timeout event really has been sent out. We now remove this unnecessary complexity, by merging data and functionality of the subscriber structure into struct tipc_conn and the associated file server.c. We thereafter add a spinlock and a new 'inactive' state to the subscription structure. Using those, both problems described above can be easily solved. Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-02-15 09:40:44 +00:00
struct list_head sub_list;
spinlock_t sub_lock; /* for subscription list */
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
struct work_struct rwork;
struct list_head outqueue;
spinlock_t outqueue_lock; /* for outqueue */
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
struct work_struct swork;
};
/* An entry waiting to be sent */
struct outqueue_entry {
bool inactive;
struct tipc_event evt;
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
struct list_head list;
};
static void tipc_conn_recv_work(struct work_struct *work);
static void tipc_conn_send_work(struct work_struct *work);
static void tipc_topsrv_kern_evt(struct net *net, struct tipc_event *evt);
static void tipc_conn_delete_sub(struct tipc_conn *con, struct tipc_subscr *s);
tipc: eliminate struct tipc_subscriber It is unnecessary to keep two structures, struct tipc_conn and struct tipc_subscriber, with a one-to-one relationship and still with different life cycles. The fact that the two often run in different contexts, and still may access each other via direct pointers constitutes an additional hazard, something we have experienced at several occasions, and still see happening. We have identified at least two remaining problems that are easier to fix if we simplify the topology server data structure somewhat. - When there is a race between a subscription up/down event and a timeout event, it is fully possible that the former might be delivered after the latter, leading to confusion for the receiver. - The function tipc_subcrp_timeout() is executing in interrupt context, while the following call chain is at least theoretically possible: tipc_subscrp_timeout() tipc_subscrp_send_event() tipc_conn_sendmsg() conn_put() tipc_conn_kref_release() sock_release(sock) I.e., we end up calling a function that might try to sleep in interrupt context. To eliminate this, we need to ensure that the tipc_conn structure and the socket, as well as the subscription instances, only are deleted in work queue context, i.e., after the timeout event really has been sent out. We now remove this unnecessary complexity, by merging data and functionality of the subscriber structure into struct tipc_conn and the associated file server.c. We thereafter add a spinlock and a new 'inactive' state to the subscription structure. Using those, both problems described above can be easily solved. Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-02-15 09:40:44 +00:00
static bool connected(struct tipc_conn *con)
{
return con && test_bit(CF_CONNECTED, &con->flags);
}
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
static void tipc_conn_kref_release(struct kref *kref)
{
struct tipc_conn *con = container_of(kref, struct tipc_conn, kref);
struct tipc_topsrv *s = con->server;
struct outqueue_entry *e, *safe;
tipc: fix netns refcnt leak When the TIPC module is loaded, we launch a topology server in kernel space, which in its turn is creating TIPC sockets for communication with topology server users. Because both the socket's creator and provider reside in the same module, it is necessary that the TIPC module's reference count remains zero after the server is started and the socket created; otherwise it becomes impossible to perform "rmmod" even on an idle module. Currently, we achieve this by defining a separate "tipc_proto_kern" protocol struct, that is used only for kernel space socket allocations. This structure has the "owner" field set to NULL, which restricts the module reference count from being be bumped when sk_alloc() for local sockets is called. Furthermore, we have defined three kernel-specific functions, tipc_sock_create_local(), tipc_sock_release_local() and tipc_sock_accept_local(), to avoid the module counter being modified when module local sockets are created or deleted. This has worked well until we introduced name space support. However, after name space support was introduced, we have observed that a reference count leak occurs, because the netns counter is not decremented in tipc_sock_delete_local(). This commit remedies this problem. But instead of just modifying tipc_sock_delete_local(), we eliminate the whole parallel socket handling infrastructure, and start using the regular sk_create_kern(), kernel_accept() and sk_release_kernel() calls. Since those functions manipulate the module counter, we must now compensate for that by explicitly decrementing the counter after module local sockets are created, and increment it just before calling sk_release_kernel(). Fixes: a62fbccecd62 ("tipc: make subscriber server support net namespace") Signed-off-by: Ying Xue <ying.xue@windriver.com> Reviewed-by: Jon Maloy <jon.maloy@ericson.com> Reviewed-by: Erik Hugne <erik.hugne@ericsson.com> Reported-by: Cong Wang <cwang@twopensource.com> Tested-by: Erik Hugne <erik.hugne@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-18 01:32:57 +00:00
spin_lock_bh(&s->idr_lock);
idr_remove(&s->conn_idr, con->conid);
s->idr_in_use--;
spin_unlock_bh(&s->idr_lock);
if (con->sock)
sock_release(con->sock);
spin_lock_bh(&con->outqueue_lock);
list_for_each_entry_safe(e, safe, &con->outqueue, list) {
list_del(&e->list);
kfree(e);
}
spin_unlock_bh(&con->outqueue_lock);
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
kfree(con);
}
static void conn_put(struct tipc_conn *con)
{
kref_put(&con->kref, tipc_conn_kref_release);
}
static void conn_get(struct tipc_conn *con)
{
kref_get(&con->kref);
}
static void tipc_conn_close(struct tipc_conn *con)
tipc: fix a race condition leading to subscriber refcnt bug Until now, the requests sent to topology server are queued to a workqueue by the generic server framework. These messages are processed by worker threads and trigger the registered callbacks. To reduce latency on uniprocessor systems, explicit rescheduling is performed using cond_resched() after MAX_RECV_MSG_COUNT(25) messages. This implementation on SMP systems leads to an subscriber refcnt error as described below: When a worker thread yields by calling cond_resched() in a SMP system, a new worker is created on another CPU to process the pending workitem. Sometimes the sleeping thread wakes up before the new thread finishes execution. This breaks the assumption on ordering and being single threaded. The fault is more frequent when MAX_RECV_MSG_COUNT is lowered. If the first thread was processing subscription create and the second thread processing close(), the close request will free the subscriber and the create request oops as follows: [31.224137] WARNING: CPU: 2 PID: 266 at include/linux/kref.h:46 tipc_subscrb_rcv_cb+0x317/0x380 [tipc] [31.228143] CPU: 2 PID: 266 Comm: kworker/u8:1 Not tainted 4.5.0+ #97 [31.228377] Workqueue: tipc_rcv tipc_recv_work [tipc] [...] [31.228377] Call Trace: [31.228377] [<ffffffff812fbb6b>] dump_stack+0x4d/0x72 [31.228377] [<ffffffff8105a311>] __warn+0xd1/0xf0 [31.228377] [<ffffffff8105a3fd>] warn_slowpath_null+0x1d/0x20 [31.228377] [<ffffffffa0098067>] tipc_subscrb_rcv_cb+0x317/0x380 [tipc] [31.228377] [<ffffffffa00a4984>] tipc_receive_from_sock+0xd4/0x130 [tipc] [31.228377] [<ffffffffa00a439b>] tipc_recv_work+0x2b/0x50 [tipc] [31.228377] [<ffffffff81071925>] process_one_work+0x145/0x3d0 [31.246554] ---[ end trace c3882c9baa05a4fd ]--- [31.248327] BUG: spinlock bad magic on CPU#2, kworker/u8:1/266 [31.249119] BUG: unable to handle kernel NULL pointer dereference at 0000000000000428 [31.249323] IP: [<ffffffff81099d0c>] spin_dump+0x5c/0xe0 [31.249323] PGD 0 [31.249323] Oops: 0000 [#1] SMP In this commit, we - rename tipc_conn_shutdown() to tipc_conn_release(). - move connection release callback execution from tipc_close_conn() to a new function tipc_sock_release(), which is executed before we free the connection. Thus we release the subscriber during connection release procedure rather than connection shutdown procedure. Signed-off-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-12 11:05:21 +00:00
{
tipc: fix race condition at topology server receive We have identified a race condition during reception of socket events and messages in the topology server. - The function tipc_close_conn() is releasing the corresponding struct tipc_subscriber instance without considering that there may still be items in the receive work queue. When those are scheduled, in the function tipc_receive_from_work(), they are using the subscriber pointer stored in struct tipc_conn, without first checking if this is valid or not. This will sometimes lead to crashes, as the next call of tipc_conn_recvmsg() will access the now deleted item. We fix this by making the usage of this pointer conditional on whether the connection is active or not. I.e., we check the condition test_bit(CF_CONNECTED) before making the call tipc_conn_recvmsg(). - Since the two functions may be running on different cores, the condition test described above is not enough. tipc_close_conn() may come in between and delete the subscriber item after the condition test is done, but before tipc_conn_recv_msg() is finished. This happens less frequently than the problem described above, but leads to the same symptoms. We fix this by using the existing sk_callback_lock for mutual exclusion in the two functions. In addition, we have to move a call to tipc_conn_terminate() outside the mentioned lock to avoid deadlock. Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-15 16:56:28 +00:00
struct sock *sk = con->sock->sk;
bool disconnect = false;
tipc: fix a race condition leading to subscriber refcnt bug Until now, the requests sent to topology server are queued to a workqueue by the generic server framework. These messages are processed by worker threads and trigger the registered callbacks. To reduce latency on uniprocessor systems, explicit rescheduling is performed using cond_resched() after MAX_RECV_MSG_COUNT(25) messages. This implementation on SMP systems leads to an subscriber refcnt error as described below: When a worker thread yields by calling cond_resched() in a SMP system, a new worker is created on another CPU to process the pending workitem. Sometimes the sleeping thread wakes up before the new thread finishes execution. This breaks the assumption on ordering and being single threaded. The fault is more frequent when MAX_RECV_MSG_COUNT is lowered. If the first thread was processing subscription create and the second thread processing close(), the close request will free the subscriber and the create request oops as follows: [31.224137] WARNING: CPU: 2 PID: 266 at include/linux/kref.h:46 tipc_subscrb_rcv_cb+0x317/0x380 [tipc] [31.228143] CPU: 2 PID: 266 Comm: kworker/u8:1 Not tainted 4.5.0+ #97 [31.228377] Workqueue: tipc_rcv tipc_recv_work [tipc] [...] [31.228377] Call Trace: [31.228377] [<ffffffff812fbb6b>] dump_stack+0x4d/0x72 [31.228377] [<ffffffff8105a311>] __warn+0xd1/0xf0 [31.228377] [<ffffffff8105a3fd>] warn_slowpath_null+0x1d/0x20 [31.228377] [<ffffffffa0098067>] tipc_subscrb_rcv_cb+0x317/0x380 [tipc] [31.228377] [<ffffffffa00a4984>] tipc_receive_from_sock+0xd4/0x130 [tipc] [31.228377] [<ffffffffa00a439b>] tipc_recv_work+0x2b/0x50 [tipc] [31.228377] [<ffffffff81071925>] process_one_work+0x145/0x3d0 [31.246554] ---[ end trace c3882c9baa05a4fd ]--- [31.248327] BUG: spinlock bad magic on CPU#2, kworker/u8:1/266 [31.249119] BUG: unable to handle kernel NULL pointer dereference at 0000000000000428 [31.249323] IP: [<ffffffff81099d0c>] spin_dump+0x5c/0xe0 [31.249323] PGD 0 [31.249323] Oops: 0000 [#1] SMP In this commit, we - rename tipc_conn_shutdown() to tipc_conn_release(). - move connection release callback execution from tipc_close_conn() to a new function tipc_sock_release(), which is executed before we free the connection. Thus we release the subscriber during connection release procedure rather than connection shutdown procedure. Signed-off-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-12 11:05:21 +00:00
tipc: fix race condition at topology server receive We have identified a race condition during reception of socket events and messages in the topology server. - The function tipc_close_conn() is releasing the corresponding struct tipc_subscriber instance without considering that there may still be items in the receive work queue. When those are scheduled, in the function tipc_receive_from_work(), they are using the subscriber pointer stored in struct tipc_conn, without first checking if this is valid or not. This will sometimes lead to crashes, as the next call of tipc_conn_recvmsg() will access the now deleted item. We fix this by making the usage of this pointer conditional on whether the connection is active or not. I.e., we check the condition test_bit(CF_CONNECTED) before making the call tipc_conn_recvmsg(). - Since the two functions may be running on different cores, the condition test described above is not enough. tipc_close_conn() may come in between and delete the subscriber item after the condition test is done, but before tipc_conn_recv_msg() is finished. This happens less frequently than the problem described above, but leads to the same symptoms. We fix this by using the existing sk_callback_lock for mutual exclusion in the two functions. In addition, we have to move a call to tipc_conn_terminate() outside the mentioned lock to avoid deadlock. Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-15 16:56:28 +00:00
write_lock_bh(&sk->sk_callback_lock);
disconnect = test_and_clear_bit(CF_CONNECTED, &con->flags);
tipc: eliminate struct tipc_subscriber It is unnecessary to keep two structures, struct tipc_conn and struct tipc_subscriber, with a one-to-one relationship and still with different life cycles. The fact that the two often run in different contexts, and still may access each other via direct pointers constitutes an additional hazard, something we have experienced at several occasions, and still see happening. We have identified at least two remaining problems that are easier to fix if we simplify the topology server data structure somewhat. - When there is a race between a subscription up/down event and a timeout event, it is fully possible that the former might be delivered after the latter, leading to confusion for the receiver. - The function tipc_subcrp_timeout() is executing in interrupt context, while the following call chain is at least theoretically possible: tipc_subscrp_timeout() tipc_subscrp_send_event() tipc_conn_sendmsg() conn_put() tipc_conn_kref_release() sock_release(sock) I.e., we end up calling a function that might try to sleep in interrupt context. To eliminate this, we need to ensure that the tipc_conn structure and the socket, as well as the subscription instances, only are deleted in work queue context, i.e., after the timeout event really has been sent out. We now remove this unnecessary complexity, by merging data and functionality of the subscriber structure into struct tipc_conn and the associated file server.c. We thereafter add a spinlock and a new 'inactive' state to the subscription structure. Using those, both problems described above can be easily solved. Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-02-15 09:40:44 +00:00
tipc: fix race condition at topology server receive We have identified a race condition during reception of socket events and messages in the topology server. - The function tipc_close_conn() is releasing the corresponding struct tipc_subscriber instance without considering that there may still be items in the receive work queue. When those are scheduled, in the function tipc_receive_from_work(), they are using the subscriber pointer stored in struct tipc_conn, without first checking if this is valid or not. This will sometimes lead to crashes, as the next call of tipc_conn_recvmsg() will access the now deleted item. We fix this by making the usage of this pointer conditional on whether the connection is active or not. I.e., we check the condition test_bit(CF_CONNECTED) before making the call tipc_conn_recvmsg(). - Since the two functions may be running on different cores, the condition test described above is not enough. tipc_close_conn() may come in between and delete the subscriber item after the condition test is done, but before tipc_conn_recv_msg() is finished. This happens less frequently than the problem described above, but leads to the same symptoms. We fix this by using the existing sk_callback_lock for mutual exclusion in the two functions. In addition, we have to move a call to tipc_conn_terminate() outside the mentioned lock to avoid deadlock. Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-15 16:56:28 +00:00
if (disconnect) {
sk->sk_user_data = NULL;
tipc_conn_delete_sub(con, NULL);
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
}
tipc: fix race condition at topology server receive We have identified a race condition during reception of socket events and messages in the topology server. - The function tipc_close_conn() is releasing the corresponding struct tipc_subscriber instance without considering that there may still be items in the receive work queue. When those are scheduled, in the function tipc_receive_from_work(), they are using the subscriber pointer stored in struct tipc_conn, without first checking if this is valid or not. This will sometimes lead to crashes, as the next call of tipc_conn_recvmsg() will access the now deleted item. We fix this by making the usage of this pointer conditional on whether the connection is active or not. I.e., we check the condition test_bit(CF_CONNECTED) before making the call tipc_conn_recvmsg(). - Since the two functions may be running on different cores, the condition test described above is not enough. tipc_close_conn() may come in between and delete the subscriber item after the condition test is done, but before tipc_conn_recv_msg() is finished. This happens less frequently than the problem described above, but leads to the same symptoms. We fix this by using the existing sk_callback_lock for mutual exclusion in the two functions. In addition, we have to move a call to tipc_conn_terminate() outside the mentioned lock to avoid deadlock. Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-15 16:56:28 +00:00
write_unlock_bh(&sk->sk_callback_lock);
/* Handle concurrent calls from sending and receiving threads */
if (!disconnect)
return;
/* Don't flush pending works, -just let them expire */
kernel_sock_shutdown(con->sock, SHUT_RDWR);
tipc: fix race condition at topology server receive We have identified a race condition during reception of socket events and messages in the topology server. - The function tipc_close_conn() is releasing the corresponding struct tipc_subscriber instance without considering that there may still be items in the receive work queue. When those are scheduled, in the function tipc_receive_from_work(), they are using the subscriber pointer stored in struct tipc_conn, without first checking if this is valid or not. This will sometimes lead to crashes, as the next call of tipc_conn_recvmsg() will access the now deleted item. We fix this by making the usage of this pointer conditional on whether the connection is active or not. I.e., we check the condition test_bit(CF_CONNECTED) before making the call tipc_conn_recvmsg(). - Since the two functions may be running on different cores, the condition test described above is not enough. tipc_close_conn() may come in between and delete the subscriber item after the condition test is done, but before tipc_conn_recv_msg() is finished. This happens less frequently than the problem described above, but leads to the same symptoms. We fix this by using the existing sk_callback_lock for mutual exclusion in the two functions. In addition, we have to move a call to tipc_conn_terminate() outside the mentioned lock to avoid deadlock. Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-15 16:56:28 +00:00
conn_put(con);
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
}
static struct tipc_conn *tipc_conn_alloc(struct tipc_topsrv *s)
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
{
struct tipc_conn *con;
int ret;
con = kzalloc(sizeof(*con), GFP_ATOMIC);
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
if (!con)
return ERR_PTR(-ENOMEM);
kref_init(&con->kref);
INIT_LIST_HEAD(&con->outqueue);
tipc: eliminate struct tipc_subscriber It is unnecessary to keep two structures, struct tipc_conn and struct tipc_subscriber, with a one-to-one relationship and still with different life cycles. The fact that the two often run in different contexts, and still may access each other via direct pointers constitutes an additional hazard, something we have experienced at several occasions, and still see happening. We have identified at least two remaining problems that are easier to fix if we simplify the topology server data structure somewhat. - When there is a race between a subscription up/down event and a timeout event, it is fully possible that the former might be delivered after the latter, leading to confusion for the receiver. - The function tipc_subcrp_timeout() is executing in interrupt context, while the following call chain is at least theoretically possible: tipc_subscrp_timeout() tipc_subscrp_send_event() tipc_conn_sendmsg() conn_put() tipc_conn_kref_release() sock_release(sock) I.e., we end up calling a function that might try to sleep in interrupt context. To eliminate this, we need to ensure that the tipc_conn structure and the socket, as well as the subscription instances, only are deleted in work queue context, i.e., after the timeout event really has been sent out. We now remove this unnecessary complexity, by merging data and functionality of the subscriber structure into struct tipc_conn and the associated file server.c. We thereafter add a spinlock and a new 'inactive' state to the subscription structure. Using those, both problems described above can be easily solved. Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-02-15 09:40:44 +00:00
INIT_LIST_HEAD(&con->sub_list);
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
spin_lock_init(&con->outqueue_lock);
tipc: eliminate struct tipc_subscriber It is unnecessary to keep two structures, struct tipc_conn and struct tipc_subscriber, with a one-to-one relationship and still with different life cycles. The fact that the two often run in different contexts, and still may access each other via direct pointers constitutes an additional hazard, something we have experienced at several occasions, and still see happening. We have identified at least two remaining problems that are easier to fix if we simplify the topology server data structure somewhat. - When there is a race between a subscription up/down event and a timeout event, it is fully possible that the former might be delivered after the latter, leading to confusion for the receiver. - The function tipc_subcrp_timeout() is executing in interrupt context, while the following call chain is at least theoretically possible: tipc_subscrp_timeout() tipc_subscrp_send_event() tipc_conn_sendmsg() conn_put() tipc_conn_kref_release() sock_release(sock) I.e., we end up calling a function that might try to sleep in interrupt context. To eliminate this, we need to ensure that the tipc_conn structure and the socket, as well as the subscription instances, only are deleted in work queue context, i.e., after the timeout event really has been sent out. We now remove this unnecessary complexity, by merging data and functionality of the subscriber structure into struct tipc_conn and the associated file server.c. We thereafter add a spinlock and a new 'inactive' state to the subscription structure. Using those, both problems described above can be easily solved. Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-02-15 09:40:44 +00:00
spin_lock_init(&con->sub_lock);
INIT_WORK(&con->swork, tipc_conn_send_work);
INIT_WORK(&con->rwork, tipc_conn_recv_work);
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
spin_lock_bh(&s->idr_lock);
ret = idr_alloc(&s->conn_idr, con, 0, 0, GFP_ATOMIC);
if (ret < 0) {
kfree(con);
spin_unlock_bh(&s->idr_lock);
return ERR_PTR(-ENOMEM);
}
con->conid = ret;
s->idr_in_use++;
spin_unlock_bh(&s->idr_lock);
set_bit(CF_CONNECTED, &con->flags);
con->server = s;
return con;
}
static struct tipc_conn *tipc_conn_lookup(struct tipc_topsrv *s, int conid)
tipc: eliminate struct tipc_subscriber It is unnecessary to keep two structures, struct tipc_conn and struct tipc_subscriber, with a one-to-one relationship and still with different life cycles. The fact that the two often run in different contexts, and still may access each other via direct pointers constitutes an additional hazard, something we have experienced at several occasions, and still see happening. We have identified at least two remaining problems that are easier to fix if we simplify the topology server data structure somewhat. - When there is a race between a subscription up/down event and a timeout event, it is fully possible that the former might be delivered after the latter, leading to confusion for the receiver. - The function tipc_subcrp_timeout() is executing in interrupt context, while the following call chain is at least theoretically possible: tipc_subscrp_timeout() tipc_subscrp_send_event() tipc_conn_sendmsg() conn_put() tipc_conn_kref_release() sock_release(sock) I.e., we end up calling a function that might try to sleep in interrupt context. To eliminate this, we need to ensure that the tipc_conn structure and the socket, as well as the subscription instances, only are deleted in work queue context, i.e., after the timeout event really has been sent out. We now remove this unnecessary complexity, by merging data and functionality of the subscriber structure into struct tipc_conn and the associated file server.c. We thereafter add a spinlock and a new 'inactive' state to the subscription structure. Using those, both problems described above can be easily solved. Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-02-15 09:40:44 +00:00
{
struct tipc_conn *con;
spin_lock_bh(&s->idr_lock);
con = idr_find(&s->conn_idr, conid);
if (!connected(con) || !kref_get_unless_zero(&con->kref))
con = NULL;
spin_unlock_bh(&s->idr_lock);
return con;
}
/* tipc_conn_delete_sub - delete a specific or all subscriptions
* for a given subscriber
*/
static void tipc_conn_delete_sub(struct tipc_conn *con, struct tipc_subscr *s)
{
struct tipc_net *tn = tipc_net(con->server->net);
struct list_head *sub_list = &con->sub_list;
struct tipc_subscription *sub, *tmp;
tipc: eliminate struct tipc_subscriber It is unnecessary to keep two structures, struct tipc_conn and struct tipc_subscriber, with a one-to-one relationship and still with different life cycles. The fact that the two often run in different contexts, and still may access each other via direct pointers constitutes an additional hazard, something we have experienced at several occasions, and still see happening. We have identified at least two remaining problems that are easier to fix if we simplify the topology server data structure somewhat. - When there is a race between a subscription up/down event and a timeout event, it is fully possible that the former might be delivered after the latter, leading to confusion for the receiver. - The function tipc_subcrp_timeout() is executing in interrupt context, while the following call chain is at least theoretically possible: tipc_subscrp_timeout() tipc_subscrp_send_event() tipc_conn_sendmsg() conn_put() tipc_conn_kref_release() sock_release(sock) I.e., we end up calling a function that might try to sleep in interrupt context. To eliminate this, we need to ensure that the tipc_conn structure and the socket, as well as the subscription instances, only are deleted in work queue context, i.e., after the timeout event really has been sent out. We now remove this unnecessary complexity, by merging data and functionality of the subscriber structure into struct tipc_conn and the associated file server.c. We thereafter add a spinlock and a new 'inactive' state to the subscription structure. Using those, both problems described above can be easily solved. Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-02-15 09:40:44 +00:00
spin_lock_bh(&con->sub_lock);
list_for_each_entry_safe(sub, tmp, sub_list, sub_list) {
if (!s || !memcmp(s, &sub->evt.s, sizeof(*s))) {
tipc_sub_unsubscribe(sub);
atomic_dec(&tn->subscription_count);
} else if (s) {
break;
}
}
tipc: eliminate struct tipc_subscriber It is unnecessary to keep two structures, struct tipc_conn and struct tipc_subscriber, with a one-to-one relationship and still with different life cycles. The fact that the two often run in different contexts, and still may access each other via direct pointers constitutes an additional hazard, something we have experienced at several occasions, and still see happening. We have identified at least two remaining problems that are easier to fix if we simplify the topology server data structure somewhat. - When there is a race between a subscription up/down event and a timeout event, it is fully possible that the former might be delivered after the latter, leading to confusion for the receiver. - The function tipc_subcrp_timeout() is executing in interrupt context, while the following call chain is at least theoretically possible: tipc_subscrp_timeout() tipc_subscrp_send_event() tipc_conn_sendmsg() conn_put() tipc_conn_kref_release() sock_release(sock) I.e., we end up calling a function that might try to sleep in interrupt context. To eliminate this, we need to ensure that the tipc_conn structure and the socket, as well as the subscription instances, only are deleted in work queue context, i.e., after the timeout event really has been sent out. We now remove this unnecessary complexity, by merging data and functionality of the subscriber structure into struct tipc_conn and the associated file server.c. We thereafter add a spinlock and a new 'inactive' state to the subscription structure. Using those, both problems described above can be easily solved. Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-02-15 09:40:44 +00:00
spin_unlock_bh(&con->sub_lock);
}
static void tipc_conn_send_to_sock(struct tipc_conn *con)
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
{
struct list_head *queue = &con->outqueue;
struct tipc_topsrv *srv = con->server;
struct outqueue_entry *e;
struct tipc_event *evt;
struct msghdr msg;
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
struct kvec iov;
int count = 0;
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
int ret;
spin_lock_bh(&con->outqueue_lock);
while (!list_empty(queue)) {
e = list_first_entry(queue, struct outqueue_entry, list);
evt = &e->evt;
spin_unlock_bh(&con->outqueue_lock);
if (e->inactive)
tipc_conn_delete_sub(con, &evt->s);
memset(&msg, 0, sizeof(msg));
msg.msg_flags = MSG_DONTWAIT;
iov.iov_base = evt;
iov.iov_len = sizeof(*evt);
msg.msg_name = NULL;
if (con->sock) {
ret = kernel_sendmsg(con->sock, &msg, &iov,
1, sizeof(*evt));
if (ret == -EWOULDBLOCK || ret == 0) {
cond_resched();
return;
} else if (ret < 0) {
return tipc_conn_close(con);
}
} else {
tipc_topsrv_kern_evt(srv->net, evt);
}
/* Don't starve users filling buffers */
if (++count >= MAX_SEND_MSG_COUNT) {
cond_resched();
count = 0;
}
spin_lock_bh(&con->outqueue_lock);
list_del(&e->list);
kfree(e);
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
}
spin_unlock_bh(&con->outqueue_lock);
}
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
static void tipc_conn_send_work(struct work_struct *work)
{
struct tipc_conn *con = container_of(work, struct tipc_conn, swork);
if (connected(con))
tipc_conn_send_to_sock(con);
conn_put(con);
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
}
/* tipc_topsrv_queue_evt() - interrupt level call from a subscription instance
* The queued work is launched into tipc_conn_send_work()->tipc_conn_send_to_sock()
*/
void tipc_topsrv_queue_evt(struct net *net, int conid,
u32 event, struct tipc_event *evt)
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
{
struct tipc_topsrv *srv = tipc_topsrv(net);
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
struct outqueue_entry *e;
struct tipc_conn *con;
con = tipc_conn_lookup(srv, conid);
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
if (!con)
return;
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
if (!connected(con))
goto err;
e = kmalloc(sizeof(*e), GFP_ATOMIC);
if (!e)
goto err;
e->inactive = (event == TIPC_SUBSCR_TIMEOUT);
memcpy(&e->evt, evt, sizeof(*evt));
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
spin_lock_bh(&con->outqueue_lock);
list_add_tail(&e->list, &con->outqueue);
spin_unlock_bh(&con->outqueue_lock);
if (queue_work(srv->send_wq, &con->swork))
return;
err:
conn_put(con);
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
}
/* tipc_conn_write_space - interrupt callback after a sendmsg EAGAIN
* Indicates that there now is more space in the send buffer
* The queued work is launched into tipc_send_work()->tipc_conn_send_to_sock()
*/
static void tipc_conn_write_space(struct sock *sk)
{
struct tipc_conn *con;
read_lock_bh(&sk->sk_callback_lock);
con = sk->sk_user_data;
if (connected(con)) {
conn_get(con);
if (!queue_work(con->server->send_wq, &con->swork))
conn_put(con);
}
read_unlock_bh(&sk->sk_callback_lock);
}
static int tipc_conn_rcv_sub(struct tipc_topsrv *srv,
struct tipc_conn *con,
struct tipc_subscr *s)
{
struct tipc_net *tn = tipc_net(srv->net);
struct tipc_subscription *sub;
if (tipc_sub_read(s, filter) & TIPC_SUB_CANCEL) {
tipc_conn_delete_sub(con, s);
return 0;
}
if (atomic_read(&tn->subscription_count) >= TIPC_MAX_SUBSCR) {
pr_warn("Subscription rejected, max (%u)\n", TIPC_MAX_SUBSCR);
return -1;
}
sub = tipc_sub_subscribe(srv->net, s, con->conid);
if (!sub)
return -1;
atomic_inc(&tn->subscription_count);
spin_lock_bh(&con->sub_lock);
list_add(&sub->sub_list, &con->sub_list);
spin_unlock_bh(&con->sub_lock);
return 0;
}
static int tipc_conn_rcv_from_sock(struct tipc_conn *con)
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
{
struct tipc_topsrv *srv = con->server;
struct sock *sk = con->sock->sk;
struct msghdr msg = {};
struct tipc_subscr s;
struct kvec iov;
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
int ret;
iov.iov_base = &s;
iov.iov_len = sizeof(s);
msg.msg_name = NULL;
iov_iter_kvec(&msg.msg_iter, READ, &iov, 1, iov.iov_len);
ret = sock_recvmsg(con->sock, &msg, MSG_DONTWAIT);
if (ret == -EWOULDBLOCK)
return -EWOULDBLOCK;
if (ret > 0) {
read_lock_bh(&sk->sk_callback_lock);
ret = tipc_conn_rcv_sub(srv, con, &s);
read_unlock_bh(&sk->sk_callback_lock);
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
}
if (ret < 0)
tipc_conn_close(con);
return ret;
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
}
static void tipc_conn_recv_work(struct work_struct *work)
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
{
struct tipc_conn *con = container_of(work, struct tipc_conn, rwork);
int count = 0;
tipc: eliminate struct tipc_subscriber It is unnecessary to keep two structures, struct tipc_conn and struct tipc_subscriber, with a one-to-one relationship and still with different life cycles. The fact that the two often run in different contexts, and still may access each other via direct pointers constitutes an additional hazard, something we have experienced at several occasions, and still see happening. We have identified at least two remaining problems that are easier to fix if we simplify the topology server data structure somewhat. - When there is a race between a subscription up/down event and a timeout event, it is fully possible that the former might be delivered after the latter, leading to confusion for the receiver. - The function tipc_subcrp_timeout() is executing in interrupt context, while the following call chain is at least theoretically possible: tipc_subscrp_timeout() tipc_subscrp_send_event() tipc_conn_sendmsg() conn_put() tipc_conn_kref_release() sock_release(sock) I.e., we end up calling a function that might try to sleep in interrupt context. To eliminate this, we need to ensure that the tipc_conn structure and the socket, as well as the subscription instances, only are deleted in work queue context, i.e., after the timeout event really has been sent out. We now remove this unnecessary complexity, by merging data and functionality of the subscriber structure into struct tipc_conn and the associated file server.c. We thereafter add a spinlock and a new 'inactive' state to the subscription structure. Using those, both problems described above can be easily solved. Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-02-15 09:40:44 +00:00
while (connected(con)) {
if (tipc_conn_rcv_from_sock(con))
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
break;
/* Don't flood Rx machine */
if (++count >= MAX_RECV_MSG_COUNT) {
cond_resched();
count = 0;
}
}
conn_put(con);
}
/* tipc_conn_data_ready - interrupt callback indicating the socket has data
* The queued work is launched into tipc_recv_work()->tipc_conn_rcv_from_sock()
*/
static void tipc_conn_data_ready(struct sock *sk)
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
{
struct tipc_conn *con;
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
read_lock_bh(&sk->sk_callback_lock);
con = sk->sk_user_data;
if (connected(con)) {
conn_get(con);
if (!queue_work(con->server->rcv_wq, &con->rwork))
conn_put(con);
}
read_unlock_bh(&sk->sk_callback_lock);
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
}
static void tipc_topsrv_accept(struct work_struct *work)
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
{
struct tipc_topsrv *srv = container_of(work, struct tipc_topsrv, awork);
struct socket *lsock = srv->listener;
struct socket *newsock;
struct tipc_conn *con;
struct sock *newsk;
int ret;
while (1) {
ret = kernel_accept(lsock, &newsock, O_NONBLOCK);
if (ret < 0)
return;
con = tipc_conn_alloc(srv);
if (IS_ERR(con)) {
ret = PTR_ERR(con);
sock_release(newsock);
return;
}
/* Register callbacks */
newsk = newsock->sk;
write_lock_bh(&newsk->sk_callback_lock);
newsk->sk_data_ready = tipc_conn_data_ready;
newsk->sk_write_space = tipc_conn_write_space;
newsk->sk_user_data = con;
con->sock = newsock;
write_unlock_bh(&newsk->sk_callback_lock);
/* Wake up receive process in case of 'SYN+' message */
newsk->sk_data_ready(newsk);
}
}
/* tipc_toprsv_listener_data_ready - interrupt callback with connection request
* The queued job is launched into tipc_topsrv_accept()
*/
static void tipc_topsrv_listener_data_ready(struct sock *sk)
{
struct tipc_topsrv *srv;
read_lock_bh(&sk->sk_callback_lock);
srv = sk->sk_user_data;
if (srv->listener)
queue_work(srv->rcv_wq, &srv->awork);
read_unlock_bh(&sk->sk_callback_lock);
}
static int tipc_topsrv_create_listener(struct tipc_topsrv *srv)
{
int imp = TIPC_CRITICAL_IMPORTANCE;
struct socket *lsock = NULL;
struct sockaddr_tipc saddr;
struct sock *sk;
int rc;
rc = sock_create_kern(srv->net, AF_TIPC, SOCK_SEQPACKET, 0, &lsock);
if (rc < 0)
return rc;
srv->listener = lsock;
sk = lsock->sk;
write_lock_bh(&sk->sk_callback_lock);
sk->sk_data_ready = tipc_topsrv_listener_data_ready;
sk->sk_user_data = srv;
write_unlock_bh(&sk->sk_callback_lock);
rc = kernel_setsockopt(lsock, SOL_TIPC, TIPC_IMPORTANCE,
(char *)&imp, sizeof(imp));
if (rc < 0)
goto err;
saddr.family = AF_TIPC;
saddr.addrtype = TIPC_ADDR_NAMESEQ;
saddr.addr.nameseq.type = TIPC_TOP_SRV;
saddr.addr.nameseq.lower = TIPC_TOP_SRV;
saddr.addr.nameseq.upper = TIPC_TOP_SRV;
saddr.scope = TIPC_NODE_SCOPE;
rc = kernel_bind(lsock, (struct sockaddr *)&saddr, sizeof(saddr));
if (rc < 0)
goto err;
rc = kernel_listen(lsock, 0);
if (rc < 0)
goto err;
/* As server's listening socket owner and creator is the same module,
* we have to decrease TIPC module reference count to guarantee that
* it remains zero after the server socket is created, otherwise,
* executing "rmmod" command is unable to make TIPC module deleted
* after TIPC module is inserted successfully.
*
* However, the reference count is ever increased twice in
* sock_create_kern(): one is to increase the reference count of owner
* of TIPC socket's proto_ops struct; another is to increment the
* reference count of owner of TIPC proto struct. Therefore, we must
* decrement the module reference count twice to ensure that it keeps
* zero after server's listening socket is created. Of course, we
* must bump the module reference count twice as well before the socket
* is closed.
*/
module_put(lsock->ops->owner);
module_put(sk->sk_prot_creator->owner);
return 0;
err:
sock_release(lsock);
return -EINVAL;
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
}
bool tipc_topsrv_kern_subscr(struct net *net, u32 port, u32 type, u32 lower,
u32 upper, u32 filter, int *conid)
{
struct tipc_subscr sub;
struct tipc_conn *con;
int rc;
sub.seq.type = type;
sub.seq.lower = lower;
sub.seq.upper = upper;
sub.timeout = TIPC_WAIT_FOREVER;
sub.filter = filter;
*(u32 *)&sub.usr_handle = port;
con = tipc_conn_alloc(tipc_topsrv(net));
if (IS_ERR(con))
return false;
*conid = con->conid;
con->sock = NULL;
rc = tipc_conn_rcv_sub(tipc_topsrv(net), con, &sub);
if (rc >= 0)
return true;
conn_put(con);
return false;
}
void tipc_topsrv_kern_unsubscr(struct net *net, int conid)
{
struct tipc_conn *con;
con = tipc_conn_lookup(tipc_topsrv(net), conid);
if (!con)
return;
test_and_clear_bit(CF_CONNECTED, &con->flags);
tipc_conn_delete_sub(con, NULL);
conn_put(con);
conn_put(con);
}
static void tipc_topsrv_kern_evt(struct net *net, struct tipc_event *evt)
{
u32 port = *(u32 *)&evt->s.usr_handle;
u32 self = tipc_own_addr(net);
struct sk_buff_head evtq;
struct sk_buff *skb;
skb = tipc_msg_create(TOP_SRV, 0, INT_H_SIZE, sizeof(*evt),
self, self, port, port, 0);
if (!skb)
return;
msg_set_dest_droppable(buf_msg(skb), true);
memcpy(msg_data(buf_msg(skb)), evt, sizeof(*evt));
skb_queue_head_init(&evtq);
__skb_queue_tail(&evtq, skb);
tipc_sk_rcv(net, &evtq);
}
static int tipc_topsrv_work_start(struct tipc_topsrv *s)
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
{
s->rcv_wq = alloc_ordered_workqueue("tipc_rcv", 0);
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
if (!s->rcv_wq) {
pr_err("can't start tipc receive workqueue\n");
return -ENOMEM;
}
s->send_wq = alloc_ordered_workqueue("tipc_send", 0);
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
if (!s->send_wq) {
pr_err("can't start tipc send workqueue\n");
destroy_workqueue(s->rcv_wq);
return -ENOMEM;
}
return 0;
}
static void tipc_topsrv_work_stop(struct tipc_topsrv *s)
{
destroy_workqueue(s->rcv_wq);
destroy_workqueue(s->send_wq);
}
int tipc_topsrv_start(struct net *net)
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
{
struct tipc_net *tn = tipc_net(net);
const char name[] = "topology_server";
struct tipc_topsrv *srv;
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
int ret;
srv = kzalloc(sizeof(*srv), GFP_ATOMIC);
if (!srv)
return -ENOMEM;
srv->net = net;
srv->max_rcvbuf_size = sizeof(struct tipc_subscr);
INIT_WORK(&srv->awork, tipc_topsrv_accept);
strscpy(srv->name, name, sizeof(srv->name));
tn->topsrv = srv;
atomic_set(&tn->subscription_count, 0);
spin_lock_init(&srv->idr_lock);
idr_init(&srv->conn_idr);
srv->idr_in_use = 0;
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
ret = tipc_topsrv_work_start(srv);
if (ret < 0)
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
return ret;
ret = tipc_topsrv_create_listener(srv);
if (ret < 0)
tipc_topsrv_work_stop(srv);
tipc: fix oops when creating server socket fails When creation of TIPC internal server socket fails, we get an oops with the following dump: BUG: unable to handle kernel NULL pointer dereference at 0000000000000020 IP: [<ffffffffa0011f49>] tipc_close_conn+0x59/0xb0 [tipc] PGD 13719067 PUD 12008067 PMD 0 Oops: 0000 [#1] SMP DEBUG_PAGEALLOC Modules linked in: tipc(+) CPU: 4 PID: 4340 Comm: insmod Not tainted 3.10.0+ #1 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007 task: ffff880014360000 ti: ffff88001374c000 task.ti: ffff88001374c000 RIP: 0010:[<ffffffffa0011f49>] [<ffffffffa0011f49>] tipc_close_conn+0x59/0xb0 [tipc] RSP: 0018:ffff88001374dc98 EFLAGS: 00010292 RAX: 0000000000000000 RBX: ffff880012ac09d8 RCX: 0000000000000000 RDX: 0000000000000046 RSI: 0000000000000001 RDI: ffff880014360000 RBP: ffff88001374dcb8 R08: 0000000000000001 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000000 R12: ffffffffa0016fa0 R13: ffffffffa0017010 R14: ffffffffa0017010 R15: ffff880012ac09d8 FS: 0000000000000000(0000) GS:ffff880016600000(0063) knlGS:00000000f76668d0 CS: 0010 DS: 002b ES: 002b CR0: 000000008005003b CR2: 0000000000000020 CR3: 0000000012227000 CR4: 00000000000006e0 Stack: ffff88001374dcb8 ffffffffa0016fa0 0000000000000000 0000000000000001 ffff88001374dcf8 ffffffffa0012922 ffff88001374dce8 00000000ffffffea ffffffffa0017100 0000000000000000 ffff8800134241a8 ffffffffa0017150 Call Trace: [<ffffffffa0012922>] tipc_server_stop+0xa2/0x1b0 [tipc] [<ffffffffa0009995>] tipc_subscr_stop+0x15/0x20 [tipc] [<ffffffffa00130f5>] tipc_core_stop+0x1d/0x33 [tipc] [<ffffffffa001f0d4>] tipc_init+0xd4/0xf8 [tipc] [<ffffffffa001f000>] ? 0xffffffffa001efff [<ffffffff8100023f>] do_one_initcall+0x3f/0x150 [<ffffffff81082f4d>] ? __blocking_notifier_call_chain+0x7d/0xd0 [<ffffffff810cc58a>] load_module+0x11aa/0x19c0 [<ffffffff810c8d60>] ? show_initstate+0x50/0x50 [<ffffffff8190311c>] ? retint_restore_args+0xe/0xe [<ffffffff810cce79>] SyS_init_module+0xd9/0x110 [<ffffffff8190dc65>] sysenter_dispatch+0x7/0x1f Code: 6c 24 70 4c 89 ef e8 b7 04 8f e1 8b 73 04 4c 89 e7 e8 7c 9e 32 e1 41 83 ac 24 b8 00 00 00 01 4c 89 ef e8 eb 0a 8f e1 48 8b 43 08 <4c> 8b 68 20 4d 8d a5 48 03 00 00 4c 89 e7 e8 04 05 8f e1 4c 89 RIP [<ffffffffa0011f49>] tipc_close_conn+0x59/0xb0 [tipc] RSP <ffff88001374dc98> CR2: 0000000000000020 ---[ end trace b02321f40e4269a3 ]--- We have the following call chain: tipc_core_start() ret = tipc_subscr_start() ret = tipc_server_start(){ server->enabled = 1; ret = tipc_open_listening_sock() } I.e., the server->enabled flag is unconditionally set to 1, whatever the return value of tipc_open_listening_sock(). This causes a crash when tipc_core_start() tries to clean up resources after a failed initialization: if (ret == failed) tipc_subscr_stop() tipc_server_stop(){ if (server->enabled) tipc_close_conn(){ NULL reference of con->sock-sk OOPS! } } To avoid this, tipc_server_start() should only set server->enabled to 1 in case of a succesful socket creation. In case of failure, it should release all allocated resources before returning. Problem introduced in commit c5fa7b3cf3cb22e4ac60485fc2dc187fe012910f ("tipc: introduce new TIPC server infrastructure") in v3.11-rc1. Note that it won't be seen often; it takes a module load under memory constrained conditions in order to trigger the failure condition. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-08-01 12:29:18 +00:00
return ret;
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
}
void tipc_topsrv_stop(struct net *net)
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
{
struct tipc_topsrv *srv = tipc_topsrv(net);
struct socket *lsock = srv->listener;
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
struct tipc_conn *con;
int id;
spin_lock_bh(&srv->idr_lock);
for (id = 0; srv->idr_in_use; id++) {
con = idr_find(&srv->conn_idr, id);
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
if (con) {
spin_unlock_bh(&srv->idr_lock);
tipc_conn_close(con);
spin_lock_bh(&srv->idr_lock);
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
}
}
__module_get(lsock->ops->owner);
__module_get(lsock->sk->sk_prot_creator->owner);
srv->listener = NULL;
spin_unlock_bh(&srv->idr_lock);
tipc: don't call sock_release() in atomic context syzbot reported a scheduling while atomic issue at netns destruction time: BUG: sleeping function called from invalid context at net/core/sock.c:2769 in_atomic(): 1, irqs_disabled(): 0, pid: 85, name: kworker/u4:3 5 locks held by kworker/u4:3/85: #0: ((wq_completion)"%s""netns"){+.+.}, at: [<00000000c9792deb>] process_one_work+0xaaf/0x1af0 kernel/workqueue.c:2084 #1: (net_cleanup_work){+.+.}, at: [<00000000adc12e2a>] process_one_work+0xb01/0x1af0 kernel/workqueue.c:2088 #2: (net_sem){++++}, at: [<000000009ccb5669>] cleanup_net+0x23f/0xd20 net/core/net_namespace.c:494 #3: (net_mutex){+.+.}, at: [<00000000a92767d9>] cleanup_net+0xa7d/0xd20 net/core/net_namespace.c:496 #4: (&(&srv->idr_lock)->rlock){+...}, at: [<000000001343e568>] spin_lock_bh include/linux/spinlock.h:315 [inline] #4: (&(&srv->idr_lock)->rlock){+...}, at: [<000000001343e568>] tipc_topsrv_stop+0x231/0x610 net/tipc/topsrv.c:685 CPU: 0 PID: 85 Comm: kworker/u4:3 Not tainted 4.16.0-rc1+ #230 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: netns cleanup_net Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:53 ___might_sleep+0x2b2/0x470 kernel/sched/core.c:6128 __might_sleep+0x95/0x190 kernel/sched/core.c:6081 lock_sock_nested+0x37/0x110 net/core/sock.c:2769 lock_sock include/net/sock.h:1463 [inline] tipc_release+0x103/0xff0 net/tipc/socket.c:572 sock_release+0x8d/0x1e0 net/socket.c:594 tipc_topsrv_stop+0x3c0/0x610 net/tipc/topsrv.c:696 tipc_exit_net+0x15/0x40 net/tipc/core.c:96 ops_exit_list.isra.6+0xae/0x150 net/core/net_namespace.c:148 cleanup_net+0x6ba/0xd20 net/core/net_namespace.c:529 process_one_work+0xbbf/0x1af0 kernel/workqueue.c:2113 worker_thread+0x223/0x1990 kernel/workqueue.c:2247 kthread+0x33c/0x400 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:429 This is caused by tipc_topsrv_stop() releasing the listener socket with the idr lock held. This changeset addresses the issue moving the release operation outside such lock. Reported-and-tested-by: syzbot+749d9d87c294c00ca856@syzkaller.appspotmail.com Fixes: 0ef897be12b8 ("tipc: separate topology server listener socket from subcsriber sockets") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Acked-by: ///jon Signed-off-by: David S. Miller <davem@davemloft.net>
2018-02-19 18:02:24 +00:00
sock_release(lsock);
tipc_topsrv_work_stop(srv);
idr_destroy(&srv->conn_idr);
kfree(srv);
tipc: introduce new TIPC server infrastructure TIPC has two internal servers, one providing a subscription service for topology events, and another providing the configuration interface. These servers have previously been running in BH context, accessing the TIPC-port (aka native) API directly. Apart from these servers, even the TIPC socket implementation is partially built on this API. As this API may simultaneously be called via different paths and in different contexts, a complex and costly lock policiy is required in order to protect TIPC internal resources. To eliminate the need for this complex lock policiy, we introduce a new, generic service API that uses kernel sockets for message passing instead of the native API. Once the toplogy and configuration servers are converted to use this new service, all code pertaining to the native API can be removed. This entails a significant reduction in code amount and complexity, and opens up for a complete rework of the locking policy in TIPC. The new service also solves another problem: As the current topology server works in BH context, it cannot easily be blocked when sending of events fails due to congestion. In such cases events may have to be silently dropped, something that is unacceptable. Therefore, the new service keeps a dedicated outbound queue receiving messages from BH context. Once messages are inserted into this queue, we will immediately schedule a work from a special workqueue. This way, messages/events from the topology server are in reality sent in process context, and the server can block if necessary. Analogously, there is a new workqueue for receiving messages. Once a notification about an arriving message is received in BH context, we schedule a work from the receive workqueue to do the job of receiving the message in process context. As both sending and receive messages are now finished in processes, subscribed events cannot be dropped any more. As of this commit, this new server infrastructure is built, but not actually yet called by the existing TIPC code, but since the conversion changes required in order to use it are significant, the addition is kept here as a separate commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-17 14:54:39 +00:00
}