linux/net/rds/connection.c

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/*
* Copyright (c) 2006, 2018 Oracle and/or its affiliates. All rights reserved.
*
* This software is available to you under a choice of one of two
* licenses. You may choose to be licensed under the terms of the GNU
* General Public License (GPL) Version 2, available from the file
* COPYING in the main directory of this source tree, or the
* OpenIB.org BSD license below:
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above
* copyright notice, this list of conditions and the following
* disclaimer.
*
* - 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.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
*/
#include <linux/kernel.h>
#include <linux/list.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 08:04:11 +00:00
#include <linux/slab.h>
#include <linux/export.h>
#include <net/ipv6.h>
#include <net/inet6_hashtables.h>
#include <net/addrconf.h>
#include "rds.h"
#include "loop.h"
#define RDS_CONNECTION_HASH_BITS 12
#define RDS_CONNECTION_HASH_ENTRIES (1 << RDS_CONNECTION_HASH_BITS)
#define RDS_CONNECTION_HASH_MASK (RDS_CONNECTION_HASH_ENTRIES - 1)
/* converting this to RCU is a chore for another day.. */
static DEFINE_SPINLOCK(rds_conn_lock);
static unsigned long rds_conn_count;
static struct hlist_head rds_conn_hash[RDS_CONNECTION_HASH_ENTRIES];
static struct kmem_cache *rds_conn_slab;
static struct hlist_head *rds_conn_bucket(const struct in6_addr *laddr,
const struct in6_addr *faddr)
{
static u32 rds6_hash_secret __read_mostly;
static u32 rds_hash_secret __read_mostly;
u32 lhash, fhash, hash;
net_get_random_once(&rds_hash_secret, sizeof(rds_hash_secret));
net_get_random_once(&rds6_hash_secret, sizeof(rds6_hash_secret));
lhash = (__force u32)laddr->s6_addr32[3];
#if IS_ENABLED(CONFIG_IPV6)
fhash = __ipv6_addr_jhash(faddr, rds6_hash_secret);
#else
fhash = (__force u32)faddr->s6_addr32[3];
#endif
hash = __inet_ehashfn(lhash, 0, fhash, 0, rds_hash_secret);
return &rds_conn_hash[hash & RDS_CONNECTION_HASH_MASK];
}
#define rds_conn_info_set(var, test, suffix) do { \
if (test) \
var |= RDS_INFO_CONNECTION_FLAG_##suffix; \
} while (0)
/* rcu read lock must be held or the connection spinlock */
static struct rds_connection *rds_conn_lookup(struct net *net,
struct hlist_head *head,
const struct in6_addr *laddr,
const struct in6_addr *faddr,
struct rds_transport *trans,
u8 tos, int dev_if)
{
struct rds_connection *conn, *ret = NULL;
hlist: drop the node parameter from iterators I'm not sure why, but the hlist for each entry iterators were conceived list_for_each_entry(pos, head, member) The hlist ones were greedy and wanted an extra parameter: hlist_for_each_entry(tpos, pos, head, member) Why did they need an extra pos parameter? I'm not quite sure. Not only they don't really need it, it also prevents the iterator from looking exactly like the list iterator, which is unfortunate. Besides the semantic patch, there was some manual work required: - Fix up the actual hlist iterators in linux/list.h - Fix up the declaration of other iterators based on the hlist ones. - A very small amount of places were using the 'node' parameter, this was modified to use 'obj->member' instead. - Coccinelle didn't handle the hlist_for_each_entry_safe iterator properly, so those had to be fixed up manually. The semantic patch which is mostly the work of Peter Senna Tschudin is here: @@ iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host; type T; expression a,c,d,e; identifier b; statement S; @@ -T b; <+... when != b ( hlist_for_each_entry(a, - b, c, d) S | hlist_for_each_entry_continue(a, - b, c) S | hlist_for_each_entry_from(a, - b, c) S | hlist_for_each_entry_rcu(a, - b, c, d) S | hlist_for_each_entry_rcu_bh(a, - b, c, d) S | hlist_for_each_entry_continue_rcu_bh(a, - b, c) S | for_each_busy_worker(a, c, - b, d) S | ax25_uid_for_each(a, - b, c) S | ax25_for_each(a, - b, c) S | inet_bind_bucket_for_each(a, - b, c) S | sctp_for_each_hentry(a, - b, c) S | sk_for_each(a, - b, c) S | sk_for_each_rcu(a, - b, c) S | sk_for_each_from -(a, b) +(a) S + sk_for_each_from(a) S | sk_for_each_safe(a, - b, c, d) S | sk_for_each_bound(a, - b, c) S | hlist_for_each_entry_safe(a, - b, c, d, e) S | hlist_for_each_entry_continue_rcu(a, - b, c) S | nr_neigh_for_each(a, - b, c) S | nr_neigh_for_each_safe(a, - b, c, d) S | nr_node_for_each(a, - b, c) S | nr_node_for_each_safe(a, - b, c, d) S | - for_each_gfn_sp(a, c, d, b) S + for_each_gfn_sp(a, c, d) S | - for_each_gfn_indirect_valid_sp(a, c, d, b) S + for_each_gfn_indirect_valid_sp(a, c, d) S | for_each_host(a, - b, c) S | for_each_host_safe(a, - b, c, d) S | for_each_mesh_entry(a, - b, c, d) S ) ...+> [akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c] [akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c] [akpm@linux-foundation.org: checkpatch fixes] [akpm@linux-foundation.org: fix warnings] [akpm@linux-foudnation.org: redo intrusive kvm changes] Tested-by: Peter Senna Tschudin <peter.senna@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Gleb Natapov <gleb@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-28 01:06:00 +00:00
hlist_for_each_entry_rcu(conn, head, c_hash_node) {
if (ipv6_addr_equal(&conn->c_faddr, faddr) &&
ipv6_addr_equal(&conn->c_laddr, laddr) &&
conn->c_trans == trans &&
conn->c_tos == tos &&
net == rds_conn_net(conn) &&
conn->c_dev_if == dev_if) {
ret = conn;
break;
}
}
rdsdebug("returning conn %p for %pI6c -> %pI6c\n", ret,
laddr, faddr);
return ret;
}
/*
* This is called by transports as they're bringing down a connection.
* It clears partial message state so that the transport can start sending
* and receiving over this connection again in the future. It is up to
* the transport to have serialized this call with its send and recv.
*/
static void rds_conn_path_reset(struct rds_conn_path *cp)
{
struct rds_connection *conn = cp->cp_conn;
rdsdebug("connection %pI6c to %pI6c reset\n",
&conn->c_laddr, &conn->c_faddr);
rds_stats_inc(s_conn_reset);
rds_send_path_reset(cp);
cp->cp_flags = 0;
/* Do not clear next_rx_seq here, else we cannot distinguish
* retransmitted packets from new packets, and will hand all
* of them to the application. That is not consistent with the
* reliability guarantees of RDS. */
}
static void __rds_conn_path_init(struct rds_connection *conn,
struct rds_conn_path *cp, bool is_outgoing)
{
spin_lock_init(&cp->cp_lock);
cp->cp_next_tx_seq = 1;
init_waitqueue_head(&cp->cp_waitq);
INIT_LIST_HEAD(&cp->cp_send_queue);
INIT_LIST_HEAD(&cp->cp_retrans);
cp->cp_conn = conn;
atomic_set(&cp->cp_state, RDS_CONN_DOWN);
cp->cp_send_gen = 0;
cp->cp_reconnect_jiffies = 0;
cp->cp_conn->c_proposed_version = RDS_PROTOCOL_VERSION;
INIT_DELAYED_WORK(&cp->cp_send_w, rds_send_worker);
INIT_DELAYED_WORK(&cp->cp_recv_w, rds_recv_worker);
INIT_DELAYED_WORK(&cp->cp_conn_w, rds_connect_worker);
INIT_WORK(&cp->cp_down_w, rds_shutdown_worker);
mutex_init(&cp->cp_cm_lock);
cp->cp_flags = 0;
}
/*
* There is only every one 'conn' for a given pair of addresses in the
* system at a time. They contain messages to be retransmitted and so
* span the lifetime of the actual underlying transport connections.
*
* For now they are not garbage collected once they're created. They
* are torn down as the module is removed, if ever.
*/
static struct rds_connection *__rds_conn_create(struct net *net,
const struct in6_addr *laddr,
const struct in6_addr *faddr,
struct rds_transport *trans,
gfp_t gfp, u8 tos,
int is_outgoing,
int dev_if)
{
struct rds_connection *conn, *parent = NULL;
struct hlist_head *head = rds_conn_bucket(laddr, faddr);
struct rds_transport *loop_trans;
unsigned long flags;
int ret, i;
int npaths = (trans->t_mp_capable ? RDS_MPATH_WORKERS : 1);
rcu_read_lock();
conn = rds_conn_lookup(net, head, laddr, faddr, trans, tos, dev_if);
if (conn &&
conn->c_loopback &&
conn->c_trans != &rds_loop_transport &&
ipv6_addr_equal(laddr, faddr) &&
!is_outgoing) {
/* This is a looped back IB connection, and we're
* called by the code handling the incoming connect.
* We need a second connection object into which we
* can stick the other QP. */
parent = conn;
conn = parent->c_passive;
}
rcu_read_unlock();
if (conn)
goto out;
conn = kmem_cache_zalloc(rds_conn_slab, gfp);
if (!conn) {
conn = ERR_PTR(-ENOMEM);
goto out;
}
conn->c_path = kcalloc(npaths, sizeof(struct rds_conn_path), gfp);
if (!conn->c_path) {
kmem_cache_free(rds_conn_slab, conn);
conn = ERR_PTR(-ENOMEM);
goto out;
}
INIT_HLIST_NODE(&conn->c_hash_node);
conn->c_laddr = *laddr;
conn->c_isv6 = !ipv6_addr_v4mapped(laddr);
conn->c_faddr = *faddr;
conn->c_dev_if = dev_if;
conn->c_tos = tos;
#if IS_ENABLED(CONFIG_IPV6)
/* If the local address is link local, set c_bound_if to be the
* index used for this connection. Otherwise, set it to 0 as
* the socket is not bound to an interface. c_bound_if is used
* to look up a socket when a packet is received
*/
if (ipv6_addr_type(laddr) & IPV6_ADDR_LINKLOCAL)
conn->c_bound_if = dev_if;
else
#endif
conn->c_bound_if = 0;
rds_conn_net_set(conn, net);
ret = rds_cong_get_maps(conn);
if (ret) {
kfree(conn->c_path);
kmem_cache_free(rds_conn_slab, conn);
conn = ERR_PTR(ret);
goto out;
}
/*
* This is where a connection becomes loopback. If *any* RDS sockets
* can bind to the destination address then we'd rather the messages
* flow through loopback rather than either transport.
*/
loop_trans = rds_trans_get_preferred(net, faddr, conn->c_dev_if);
if (loop_trans) {
rds_trans_put(loop_trans);
conn->c_loopback = 1;
if (is_outgoing && trans->t_prefer_loopback) {
/* "outgoing" connection - and the transport
* says it wants the connection handled by the
* loopback transport. This is what TCP does.
*/
trans = &rds_loop_transport;
}
}
conn->c_trans = trans;
init_waitqueue_head(&conn->c_hs_waitq);
for (i = 0; i < npaths; i++) {
__rds_conn_path_init(conn, &conn->c_path[i],
is_outgoing);
conn->c_path[i].cp_index = i;
}
rds: tcp: use rds_destroy_pending() to synchronize netns/module teardown and rds connection/workq management An rds_connection can get added during netns deletion between lines 528 and 529 of 506 static void rds_tcp_kill_sock(struct net *net) : /* code to pull out all the rds_connections that should be destroyed */ : 528 spin_unlock_irq(&rds_tcp_conn_lock); 529 list_for_each_entry_safe(tc, _tc, &tmp_list, t_tcp_node) 530 rds_conn_destroy(tc->t_cpath->cp_conn); Such an rds_connection would miss out the rds_conn_destroy() loop (that cancels all pending work) and (if it was scheduled after netns deletion) could trigger the use-after-free. A similar race-window exists for the module unload path in rds_tcp_exit -> rds_tcp_destroy_conns Concurrency with netns deletion (rds_tcp_kill_sock()) must be handled by checking check_net() before enqueuing new work or adding new connections. Concurrency with module-unload is handled by maintaining a module specific flag that is set at the start of the module exit function, and must be checked before enqueuing new work or adding new connections. This commit refactors existing RDS_DESTROY_PENDING checks added by commit 3db6e0d172c9 ("rds: use RCU to synchronize work-enqueue with connection teardown") and consolidates all the concurrency checks listed above into the function rds_destroy_pending(). Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-02-03 12:26:51 +00:00
rcu_read_lock();
if (rds_destroy_pending(conn))
ret = -ENETDOWN;
else
ret = trans->conn_alloc(conn, GFP_ATOMIC);
if (ret) {
rds: tcp: use rds_destroy_pending() to synchronize netns/module teardown and rds connection/workq management An rds_connection can get added during netns deletion between lines 528 and 529 of 506 static void rds_tcp_kill_sock(struct net *net) : /* code to pull out all the rds_connections that should be destroyed */ : 528 spin_unlock_irq(&rds_tcp_conn_lock); 529 list_for_each_entry_safe(tc, _tc, &tmp_list, t_tcp_node) 530 rds_conn_destroy(tc->t_cpath->cp_conn); Such an rds_connection would miss out the rds_conn_destroy() loop (that cancels all pending work) and (if it was scheduled after netns deletion) could trigger the use-after-free. A similar race-window exists for the module unload path in rds_tcp_exit -> rds_tcp_destroy_conns Concurrency with netns deletion (rds_tcp_kill_sock()) must be handled by checking check_net() before enqueuing new work or adding new connections. Concurrency with module-unload is handled by maintaining a module specific flag that is set at the start of the module exit function, and must be checked before enqueuing new work or adding new connections. This commit refactors existing RDS_DESTROY_PENDING checks added by commit 3db6e0d172c9 ("rds: use RCU to synchronize work-enqueue with connection teardown") and consolidates all the concurrency checks listed above into the function rds_destroy_pending(). Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-02-03 12:26:51 +00:00
rcu_read_unlock();
kfree(conn->c_path);
kmem_cache_free(rds_conn_slab, conn);
conn = ERR_PTR(ret);
goto out;
}
rdsdebug("allocated conn %p for %pI6c -> %pI6c over %s %s\n",
conn, laddr, faddr,
strnlen(trans->t_name, sizeof(trans->t_name)) ?
trans->t_name : "[unknown]", is_outgoing ? "(outgoing)" : "");
/*
* Since we ran without holding the conn lock, someone could
* have created the same conn (either normal or passive) in the
* interim. We check while holding the lock. If we won, we complete
* init and return our conn. If we lost, we rollback and return the
* other one.
*/
spin_lock_irqsave(&rds_conn_lock, flags);
if (parent) {
/* Creating passive conn */
if (parent->c_passive) {
trans->conn_free(conn->c_path[0].cp_transport_data);
kfree(conn->c_path);
kmem_cache_free(rds_conn_slab, conn);
conn = parent->c_passive;
} else {
parent->c_passive = conn;
rds_cong_add_conn(conn);
rds_conn_count++;
}
} else {
/* Creating normal conn */
struct rds_connection *found;
found = rds_conn_lookup(net, head, laddr, faddr, trans,
tos, dev_if);
if (found) {
struct rds_conn_path *cp;
int i;
for (i = 0; i < npaths; i++) {
cp = &conn->c_path[i];
/* The ->conn_alloc invocation may have
* allocated resource for all paths, so all
* of them may have to be freed here.
*/
if (cp->cp_transport_data)
trans->conn_free(cp->cp_transport_data);
}
kfree(conn->c_path);
kmem_cache_free(rds_conn_slab, conn);
conn = found;
} else {
2016-11-16 21:29:49 +00:00
conn->c_my_gen_num = rds_gen_num;
conn->c_peer_gen_num = 0;
2015-09-30 20:54:07 +00:00
hlist_add_head_rcu(&conn->c_hash_node, head);
rds_cong_add_conn(conn);
rds_conn_count++;
}
}
spin_unlock_irqrestore(&rds_conn_lock, flags);
rds: tcp: use rds_destroy_pending() to synchronize netns/module teardown and rds connection/workq management An rds_connection can get added during netns deletion between lines 528 and 529 of 506 static void rds_tcp_kill_sock(struct net *net) : /* code to pull out all the rds_connections that should be destroyed */ : 528 spin_unlock_irq(&rds_tcp_conn_lock); 529 list_for_each_entry_safe(tc, _tc, &tmp_list, t_tcp_node) 530 rds_conn_destroy(tc->t_cpath->cp_conn); Such an rds_connection would miss out the rds_conn_destroy() loop (that cancels all pending work) and (if it was scheduled after netns deletion) could trigger the use-after-free. A similar race-window exists for the module unload path in rds_tcp_exit -> rds_tcp_destroy_conns Concurrency with netns deletion (rds_tcp_kill_sock()) must be handled by checking check_net() before enqueuing new work or adding new connections. Concurrency with module-unload is handled by maintaining a module specific flag that is set at the start of the module exit function, and must be checked before enqueuing new work or adding new connections. This commit refactors existing RDS_DESTROY_PENDING checks added by commit 3db6e0d172c9 ("rds: use RCU to synchronize work-enqueue with connection teardown") and consolidates all the concurrency checks listed above into the function rds_destroy_pending(). Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-02-03 12:26:51 +00:00
rcu_read_unlock();
out:
return conn;
}
struct rds_connection *rds_conn_create(struct net *net,
const struct in6_addr *laddr,
const struct in6_addr *faddr,
struct rds_transport *trans, u8 tos,
gfp_t gfp, int dev_if)
{
return __rds_conn_create(net, laddr, faddr, trans, gfp, tos, 0, dev_if);
}
EXPORT_SYMBOL_GPL(rds_conn_create);
struct rds_connection *rds_conn_create_outgoing(struct net *net,
const struct in6_addr *laddr,
const struct in6_addr *faddr,
struct rds_transport *trans,
u8 tos, gfp_t gfp, int dev_if)
{
return __rds_conn_create(net, laddr, faddr, trans, gfp, tos, 1, dev_if);
}
EXPORT_SYMBOL_GPL(rds_conn_create_outgoing);
void rds_conn_shutdown(struct rds_conn_path *cp)
{
struct rds_connection *conn = cp->cp_conn;
/* shut it down unless it's down already */
if (!rds_conn_path_transition(cp, RDS_CONN_DOWN, RDS_CONN_DOWN)) {
/*
* Quiesce the connection mgmt handlers before we start tearing
* things down. We don't hold the mutex for the entire
* duration of the shutdown operation, else we may be
* deadlocking with the CM handler. Instead, the CM event
* handler is supposed to check for state DISCONNECTING
*/
mutex_lock(&cp->cp_cm_lock);
if (!rds_conn_path_transition(cp, RDS_CONN_UP,
RDS_CONN_DISCONNECTING) &&
!rds_conn_path_transition(cp, RDS_CONN_ERROR,
RDS_CONN_DISCONNECTING)) {
rds_conn_path_error(cp,
"shutdown called in state %d\n",
atomic_read(&cp->cp_state));
mutex_unlock(&cp->cp_cm_lock);
return;
}
mutex_unlock(&cp->cp_cm_lock);
wait_event(cp->cp_waitq,
!test_bit(RDS_IN_XMIT, &cp->cp_flags));
wait_event(cp->cp_waitq,
!test_bit(RDS_RECV_REFILL, &cp->cp_flags));
conn->c_trans->conn_path_shutdown(cp);
rds_conn_path_reset(cp);
if (!rds_conn_path_transition(cp, RDS_CONN_DISCONNECTING,
RDS_CONN_DOWN) &&
!rds_conn_path_transition(cp, RDS_CONN_ERROR,
RDS_CONN_DOWN)) {
/* This can happen - eg when we're in the middle of tearing
* down the connection, and someone unloads the rds module.
* Quite reproducible with loopback connections.
* Mostly harmless.
*
* Note that this also happens with rds-tcp because
* we could have triggered rds_conn_path_drop in irq
* mode from rds_tcp_state change on the receipt of
* a FIN, thus we need to recheck for RDS_CONN_ERROR
* here.
*/
rds_conn_path_error(cp, "%s: failed to transition "
"to state DOWN, current state "
"is %d\n", __func__,
atomic_read(&cp->cp_state));
return;
}
}
/* Then reconnect if it's still live.
* The passive side of an IB loopback connection is never added
* to the conn hash, so we never trigger a reconnect on this
* conn - the reconnect is always triggered by the active peer. */
cancel_delayed_work_sync(&cp->cp_conn_w);
rcu_read_lock();
if (!hlist_unhashed(&conn->c_hash_node)) {
rcu_read_unlock();
rds_queue_reconnect(cp);
} else {
rcu_read_unlock();
}
}
/* destroy a single rds_conn_path. rds_conn_destroy() iterates over
* all paths using rds_conn_path_destroy()
*/
static void rds_conn_path_destroy(struct rds_conn_path *cp)
{
struct rds_message *rm, *rtmp;
if (!cp->cp_transport_data)
return;
/* make sure lingering queued work won't try to ref the conn */
cancel_delayed_work_sync(&cp->cp_send_w);
cancel_delayed_work_sync(&cp->cp_recv_w);
rds_conn_path_drop(cp, true);
flush_work(&cp->cp_down_w);
/* tear down queued messages */
list_for_each_entry_safe(rm, rtmp,
&cp->cp_send_queue,
m_conn_item) {
list_del_init(&rm->m_conn_item);
BUG_ON(!list_empty(&rm->m_sock_item));
rds_message_put(rm);
}
if (cp->cp_xmit_rm)
rds_message_put(cp->cp_xmit_rm);
WARN_ON(delayed_work_pending(&cp->cp_send_w));
WARN_ON(delayed_work_pending(&cp->cp_recv_w));
WARN_ON(delayed_work_pending(&cp->cp_conn_w));
WARN_ON(work_pending(&cp->cp_down_w));
cp->cp_conn->c_trans->conn_free(cp->cp_transport_data);
}
/*
* Stop and free a connection.
*
* This can only be used in very limited circumstances. It assumes that once
* the conn has been shutdown that no one else is referencing the connection.
* We can only ensure this in the rmmod path in the current code.
*/
void rds_conn_destroy(struct rds_connection *conn)
{
unsigned long flags;
int i;
struct rds_conn_path *cp;
int npaths = (conn->c_trans->t_mp_capable ? RDS_MPATH_WORKERS : 1);
rdsdebug("freeing conn %p for %pI4 -> "
"%pI4\n", conn, &conn->c_laddr,
&conn->c_faddr);
/* Ensure conn will not be scheduled for reconnect */
spin_lock_irq(&rds_conn_lock);
hlist_del_init_rcu(&conn->c_hash_node);
spin_unlock_irq(&rds_conn_lock);
synchronize_rcu();
/* shut the connection down */
for (i = 0; i < npaths; i++) {
cp = &conn->c_path[i];
rds_conn_path_destroy(cp);
BUG_ON(!list_empty(&cp->cp_retrans));
}
/*
* The congestion maps aren't freed up here. They're
* freed by rds_cong_exit() after all the connections
* have been freed.
*/
rds_cong_remove_conn(conn);
kfree(conn->c_path);
kmem_cache_free(rds_conn_slab, conn);
spin_lock_irqsave(&rds_conn_lock, flags);
rds_conn_count--;
spin_unlock_irqrestore(&rds_conn_lock, flags);
}
EXPORT_SYMBOL_GPL(rds_conn_destroy);
static void __rds_inc_msg_cp(struct rds_incoming *inc,
struct rds_info_iterator *iter,
void *saddr, void *daddr, int flip, bool isv6)
{
#if IS_ENABLED(CONFIG_IPV6)
if (isv6)
rds6_inc_info_copy(inc, iter, saddr, daddr, flip);
else
#endif
rds_inc_info_copy(inc, iter, *(__be32 *)saddr,
*(__be32 *)daddr, flip);
}
static void rds_conn_message_info_cmn(struct socket *sock, unsigned int len,
struct rds_info_iterator *iter,
struct rds_info_lengths *lens,
int want_send, bool isv6)
{
struct hlist_head *head;
struct list_head *list;
struct rds_connection *conn;
struct rds_message *rm;
unsigned int total = 0;
unsigned long flags;
size_t i;
int j;
if (isv6)
len /= sizeof(struct rds6_info_message);
else
len /= sizeof(struct rds_info_message);
rcu_read_lock();
for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
i++, head++) {
hlist: drop the node parameter from iterators I'm not sure why, but the hlist for each entry iterators were conceived list_for_each_entry(pos, head, member) The hlist ones were greedy and wanted an extra parameter: hlist_for_each_entry(tpos, pos, head, member) Why did they need an extra pos parameter? I'm not quite sure. Not only they don't really need it, it also prevents the iterator from looking exactly like the list iterator, which is unfortunate. Besides the semantic patch, there was some manual work required: - Fix up the actual hlist iterators in linux/list.h - Fix up the declaration of other iterators based on the hlist ones. - A very small amount of places were using the 'node' parameter, this was modified to use 'obj->member' instead. - Coccinelle didn't handle the hlist_for_each_entry_safe iterator properly, so those had to be fixed up manually. The semantic patch which is mostly the work of Peter Senna Tschudin is here: @@ iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host; type T; expression a,c,d,e; identifier b; statement S; @@ -T b; <+... when != b ( hlist_for_each_entry(a, - b, c, d) S | hlist_for_each_entry_continue(a, - b, c) S | hlist_for_each_entry_from(a, - b, c) S | hlist_for_each_entry_rcu(a, - b, c, d) S | hlist_for_each_entry_rcu_bh(a, - b, c, d) S | hlist_for_each_entry_continue_rcu_bh(a, - b, c) S | for_each_busy_worker(a, c, - b, d) S | ax25_uid_for_each(a, - b, c) S | ax25_for_each(a, - b, c) S | inet_bind_bucket_for_each(a, - b, c) S | sctp_for_each_hentry(a, - b, c) S | sk_for_each(a, - b, c) S | sk_for_each_rcu(a, - b, c) S | sk_for_each_from -(a, b) +(a) S + sk_for_each_from(a) S | sk_for_each_safe(a, - b, c, d) S | sk_for_each_bound(a, - b, c) S | hlist_for_each_entry_safe(a, - b, c, d, e) S | hlist_for_each_entry_continue_rcu(a, - b, c) S | nr_neigh_for_each(a, - b, c) S | nr_neigh_for_each_safe(a, - b, c, d) S | nr_node_for_each(a, - b, c) S | nr_node_for_each_safe(a, - b, c, d) S | - for_each_gfn_sp(a, c, d, b) S + for_each_gfn_sp(a, c, d) S | - for_each_gfn_indirect_valid_sp(a, c, d, b) S + for_each_gfn_indirect_valid_sp(a, c, d) S | for_each_host(a, - b, c) S | for_each_host_safe(a, - b, c, d) S | for_each_mesh_entry(a, - b, c, d) S ) ...+> [akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c] [akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c] [akpm@linux-foundation.org: checkpatch fixes] [akpm@linux-foundation.org: fix warnings] [akpm@linux-foudnation.org: redo intrusive kvm changes] Tested-by: Peter Senna Tschudin <peter.senna@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Gleb Natapov <gleb@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-28 01:06:00 +00:00
hlist_for_each_entry_rcu(conn, head, c_hash_node) {
struct rds_conn_path *cp;
int npaths;
if (!isv6 && conn->c_isv6)
continue;
npaths = (conn->c_trans->t_mp_capable ?
RDS_MPATH_WORKERS : 1);
for (j = 0; j < npaths; j++) {
cp = &conn->c_path[j];
if (want_send)
list = &cp->cp_send_queue;
else
list = &cp->cp_retrans;
spin_lock_irqsave(&cp->cp_lock, flags);
/* XXX too lazy to maintain counts.. */
list_for_each_entry(rm, list, m_conn_item) {
total++;
if (total <= len)
__rds_inc_msg_cp(&rm->m_inc,
iter,
&conn->c_laddr,
&conn->c_faddr,
0, isv6);
}
spin_unlock_irqrestore(&cp->cp_lock, flags);
}
}
}
rcu_read_unlock();
lens->nr = total;
if (isv6)
lens->each = sizeof(struct rds6_info_message);
else
lens->each = sizeof(struct rds_info_message);
}
static void rds_conn_message_info(struct socket *sock, unsigned int len,
struct rds_info_iterator *iter,
struct rds_info_lengths *lens,
int want_send)
{
rds_conn_message_info_cmn(sock, len, iter, lens, want_send, false);
}
#if IS_ENABLED(CONFIG_IPV6)
static void rds6_conn_message_info(struct socket *sock, unsigned int len,
struct rds_info_iterator *iter,
struct rds_info_lengths *lens,
int want_send)
{
rds_conn_message_info_cmn(sock, len, iter, lens, want_send, true);
}
#endif
static void rds_conn_message_info_send(struct socket *sock, unsigned int len,
struct rds_info_iterator *iter,
struct rds_info_lengths *lens)
{
rds_conn_message_info(sock, len, iter, lens, 1);
}
#if IS_ENABLED(CONFIG_IPV6)
static void rds6_conn_message_info_send(struct socket *sock, unsigned int len,
struct rds_info_iterator *iter,
struct rds_info_lengths *lens)
{
rds6_conn_message_info(sock, len, iter, lens, 1);
}
#endif
static void rds_conn_message_info_retrans(struct socket *sock,
unsigned int len,
struct rds_info_iterator *iter,
struct rds_info_lengths *lens)
{
rds_conn_message_info(sock, len, iter, lens, 0);
}
#if IS_ENABLED(CONFIG_IPV6)
static void rds6_conn_message_info_retrans(struct socket *sock,
unsigned int len,
struct rds_info_iterator *iter,
struct rds_info_lengths *lens)
{
rds6_conn_message_info(sock, len, iter, lens, 0);
}
#endif
void rds_for_each_conn_info(struct socket *sock, unsigned int len,
struct rds_info_iterator *iter,
struct rds_info_lengths *lens,
int (*visitor)(struct rds_connection *, void *),
u64 *buffer,
size_t item_len)
{
struct hlist_head *head;
struct rds_connection *conn;
size_t i;
rcu_read_lock();
lens->nr = 0;
lens->each = item_len;
for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
i++, head++) {
hlist: drop the node parameter from iterators I'm not sure why, but the hlist for each entry iterators were conceived list_for_each_entry(pos, head, member) The hlist ones were greedy and wanted an extra parameter: hlist_for_each_entry(tpos, pos, head, member) Why did they need an extra pos parameter? I'm not quite sure. Not only they don't really need it, it also prevents the iterator from looking exactly like the list iterator, which is unfortunate. Besides the semantic patch, there was some manual work required: - Fix up the actual hlist iterators in linux/list.h - Fix up the declaration of other iterators based on the hlist ones. - A very small amount of places were using the 'node' parameter, this was modified to use 'obj->member' instead. - Coccinelle didn't handle the hlist_for_each_entry_safe iterator properly, so those had to be fixed up manually. The semantic patch which is mostly the work of Peter Senna Tschudin is here: @@ iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host; type T; expression a,c,d,e; identifier b; statement S; @@ -T b; <+... when != b ( hlist_for_each_entry(a, - b, c, d) S | hlist_for_each_entry_continue(a, - b, c) S | hlist_for_each_entry_from(a, - b, c) S | hlist_for_each_entry_rcu(a, - b, c, d) S | hlist_for_each_entry_rcu_bh(a, - b, c, d) S | hlist_for_each_entry_continue_rcu_bh(a, - b, c) S | for_each_busy_worker(a, c, - b, d) S | ax25_uid_for_each(a, - b, c) S | ax25_for_each(a, - b, c) S | inet_bind_bucket_for_each(a, - b, c) S | sctp_for_each_hentry(a, - b, c) S | sk_for_each(a, - b, c) S | sk_for_each_rcu(a, - b, c) S | sk_for_each_from -(a, b) +(a) S + sk_for_each_from(a) S | sk_for_each_safe(a, - b, c, d) S | sk_for_each_bound(a, - b, c) S | hlist_for_each_entry_safe(a, - b, c, d, e) S | hlist_for_each_entry_continue_rcu(a, - b, c) S | nr_neigh_for_each(a, - b, c) S | nr_neigh_for_each_safe(a, - b, c, d) S | nr_node_for_each(a, - b, c) S | nr_node_for_each_safe(a, - b, c, d) S | - for_each_gfn_sp(a, c, d, b) S + for_each_gfn_sp(a, c, d) S | - for_each_gfn_indirect_valid_sp(a, c, d, b) S + for_each_gfn_indirect_valid_sp(a, c, d) S | for_each_host(a, - b, c) S | for_each_host_safe(a, - b, c, d) S | for_each_mesh_entry(a, - b, c, d) S ) ...+> [akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c] [akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c] [akpm@linux-foundation.org: checkpatch fixes] [akpm@linux-foundation.org: fix warnings] [akpm@linux-foudnation.org: redo intrusive kvm changes] Tested-by: Peter Senna Tschudin <peter.senna@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Gleb Natapov <gleb@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-28 01:06:00 +00:00
hlist_for_each_entry_rcu(conn, head, c_hash_node) {
/* XXX no c_lock usage.. */
if (!visitor(conn, buffer))
continue;
/* We copy as much as we can fit in the buffer,
* but we count all items so that the caller
* can resize the buffer. */
if (len >= item_len) {
rds_info_copy(iter, buffer, item_len);
len -= item_len;
}
lens->nr++;
}
}
rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(rds_for_each_conn_info);
static void rds_walk_conn_path_info(struct socket *sock, unsigned int len,
struct rds_info_iterator *iter,
struct rds_info_lengths *lens,
int (*visitor)(struct rds_conn_path *, void *),
u64 *buffer,
size_t item_len)
{
struct hlist_head *head;
struct rds_connection *conn;
size_t i;
rcu_read_lock();
lens->nr = 0;
lens->each = item_len;
for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
i++, head++) {
hlist_for_each_entry_rcu(conn, head, c_hash_node) {
struct rds_conn_path *cp;
/* XXX We only copy the information from the first
* path for now. The problem is that if there are
* more than one underlying paths, we cannot report
* information of all of them using the existing
* API. For example, there is only one next_tx_seq,
* which path's next_tx_seq should we report? It is
* a bug in the design of MPRDS.
*/
cp = conn->c_path;
/* XXX no cp_lock usage.. */
if (!visitor(cp, buffer))
continue;
/* We copy as much as we can fit in the buffer,
* but we count all items so that the caller
* can resize the buffer.
*/
if (len >= item_len) {
rds_info_copy(iter, buffer, item_len);
len -= item_len;
}
lens->nr++;
}
}
rcu_read_unlock();
}
static int rds_conn_info_visitor(struct rds_conn_path *cp, void *buffer)
{
struct rds_info_connection *cinfo = buffer;
struct rds_connection *conn = cp->cp_conn;
if (conn->c_isv6)
return 0;
cinfo->next_tx_seq = cp->cp_next_tx_seq;
cinfo->next_rx_seq = cp->cp_next_rx_seq;
cinfo->laddr = conn->c_laddr.s6_addr32[3];
cinfo->faddr = conn->c_faddr.s6_addr32[3];
cinfo->tos = conn->c_tos;
strncpy(cinfo->transport, conn->c_trans->t_name,
sizeof(cinfo->transport));
cinfo->flags = 0;
rds_conn_info_set(cinfo->flags, test_bit(RDS_IN_XMIT, &cp->cp_flags),
SENDING);
/* XXX Future: return the state rather than these funky bits */
rds_conn_info_set(cinfo->flags,
atomic_read(&cp->cp_state) == RDS_CONN_CONNECTING,
CONNECTING);
rds_conn_info_set(cinfo->flags,
atomic_read(&cp->cp_state) == RDS_CONN_UP,
CONNECTED);
return 1;
}
#if IS_ENABLED(CONFIG_IPV6)
static int rds6_conn_info_visitor(struct rds_conn_path *cp, void *buffer)
{
struct rds6_info_connection *cinfo6 = buffer;
struct rds_connection *conn = cp->cp_conn;
cinfo6->next_tx_seq = cp->cp_next_tx_seq;
cinfo6->next_rx_seq = cp->cp_next_rx_seq;
cinfo6->laddr = conn->c_laddr;
cinfo6->faddr = conn->c_faddr;
strncpy(cinfo6->transport, conn->c_trans->t_name,
sizeof(cinfo6->transport));
cinfo6->flags = 0;
rds_conn_info_set(cinfo6->flags, test_bit(RDS_IN_XMIT, &cp->cp_flags),
SENDING);
/* XXX Future: return the state rather than these funky bits */
rds_conn_info_set(cinfo6->flags,
atomic_read(&cp->cp_state) == RDS_CONN_CONNECTING,
CONNECTING);
rds_conn_info_set(cinfo6->flags,
atomic_read(&cp->cp_state) == RDS_CONN_UP,
CONNECTED);
/* Just return 1 as there is no error case. This is a helper function
* for rds_walk_conn_path_info() and it wants a return value.
*/
return 1;
}
#endif
static void rds_conn_info(struct socket *sock, unsigned int len,
struct rds_info_iterator *iter,
struct rds_info_lengths *lens)
{
u64 buffer[(sizeof(struct rds_info_connection) + 7) / 8];
rds_walk_conn_path_info(sock, len, iter, lens,
rds_conn_info_visitor,
buffer,
sizeof(struct rds_info_connection));
}
#if IS_ENABLED(CONFIG_IPV6)
static void rds6_conn_info(struct socket *sock, unsigned int len,
struct rds_info_iterator *iter,
struct rds_info_lengths *lens)
{
u64 buffer[(sizeof(struct rds6_info_connection) + 7) / 8];
rds_walk_conn_path_info(sock, len, iter, lens,
rds6_conn_info_visitor,
buffer,
sizeof(struct rds6_info_connection));
}
#endif
int rds_conn_init(void)
{
int ret;
ret = rds_loop_net_init(); /* register pernet callback */
if (ret)
return ret;
rds_conn_slab = kmem_cache_create("rds_connection",
sizeof(struct rds_connection),
0, 0, NULL);
if (!rds_conn_slab) {
rds_loop_net_exit();
return -ENOMEM;
}
rds_info_register_func(RDS_INFO_CONNECTIONS, rds_conn_info);
rds_info_register_func(RDS_INFO_SEND_MESSAGES,
rds_conn_message_info_send);
rds_info_register_func(RDS_INFO_RETRANS_MESSAGES,
rds_conn_message_info_retrans);
#if IS_ENABLED(CONFIG_IPV6)
rds_info_register_func(RDS6_INFO_CONNECTIONS, rds6_conn_info);
rds_info_register_func(RDS6_INFO_SEND_MESSAGES,
rds6_conn_message_info_send);
rds_info_register_func(RDS6_INFO_RETRANS_MESSAGES,
rds6_conn_message_info_retrans);
#endif
return 0;
}
void rds_conn_exit(void)
{
rds_loop_net_exit(); /* unregister pernet callback */
rds_loop_exit();
WARN_ON(!hlist_empty(rds_conn_hash));
kmem_cache_destroy(rds_conn_slab);
rds_info_deregister_func(RDS_INFO_CONNECTIONS, rds_conn_info);
rds_info_deregister_func(RDS_INFO_SEND_MESSAGES,
rds_conn_message_info_send);
rds_info_deregister_func(RDS_INFO_RETRANS_MESSAGES,
rds_conn_message_info_retrans);
#if IS_ENABLED(CONFIG_IPV6)
rds_info_deregister_func(RDS6_INFO_CONNECTIONS, rds6_conn_info);
rds_info_deregister_func(RDS6_INFO_SEND_MESSAGES,
rds6_conn_message_info_send);
rds_info_deregister_func(RDS6_INFO_RETRANS_MESSAGES,
rds6_conn_message_info_retrans);
#endif
}
/*
* Force a disconnect
*/
void rds_conn_path_drop(struct rds_conn_path *cp, bool destroy)
{
atomic_set(&cp->cp_state, RDS_CONN_ERROR);
rcu_read_lock();
rds: tcp: use rds_destroy_pending() to synchronize netns/module teardown and rds connection/workq management An rds_connection can get added during netns deletion between lines 528 and 529 of 506 static void rds_tcp_kill_sock(struct net *net) : /* code to pull out all the rds_connections that should be destroyed */ : 528 spin_unlock_irq(&rds_tcp_conn_lock); 529 list_for_each_entry_safe(tc, _tc, &tmp_list, t_tcp_node) 530 rds_conn_destroy(tc->t_cpath->cp_conn); Such an rds_connection would miss out the rds_conn_destroy() loop (that cancels all pending work) and (if it was scheduled after netns deletion) could trigger the use-after-free. A similar race-window exists for the module unload path in rds_tcp_exit -> rds_tcp_destroy_conns Concurrency with netns deletion (rds_tcp_kill_sock()) must be handled by checking check_net() before enqueuing new work or adding new connections. Concurrency with module-unload is handled by maintaining a module specific flag that is set at the start of the module exit function, and must be checked before enqueuing new work or adding new connections. This commit refactors existing RDS_DESTROY_PENDING checks added by commit 3db6e0d172c9 ("rds: use RCU to synchronize work-enqueue with connection teardown") and consolidates all the concurrency checks listed above into the function rds_destroy_pending(). Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-02-03 12:26:51 +00:00
if (!destroy && rds_destroy_pending(cp->cp_conn)) {
rcu_read_unlock();
return;
}
queue_work(rds_wq, &cp->cp_down_w);
rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(rds_conn_path_drop);
void rds_conn_drop(struct rds_connection *conn)
{
WARN_ON(conn->c_trans->t_mp_capable);
rds_conn_path_drop(&conn->c_path[0], false);
}
EXPORT_SYMBOL_GPL(rds_conn_drop);
/*
* If the connection is down, trigger a connect. We may have scheduled a
* delayed reconnect however - in this case we should not interfere.
*/
void rds_conn_path_connect_if_down(struct rds_conn_path *cp)
{
rcu_read_lock();
rds: tcp: use rds_destroy_pending() to synchronize netns/module teardown and rds connection/workq management An rds_connection can get added during netns deletion between lines 528 and 529 of 506 static void rds_tcp_kill_sock(struct net *net) : /* code to pull out all the rds_connections that should be destroyed */ : 528 spin_unlock_irq(&rds_tcp_conn_lock); 529 list_for_each_entry_safe(tc, _tc, &tmp_list, t_tcp_node) 530 rds_conn_destroy(tc->t_cpath->cp_conn); Such an rds_connection would miss out the rds_conn_destroy() loop (that cancels all pending work) and (if it was scheduled after netns deletion) could trigger the use-after-free. A similar race-window exists for the module unload path in rds_tcp_exit -> rds_tcp_destroy_conns Concurrency with netns deletion (rds_tcp_kill_sock()) must be handled by checking check_net() before enqueuing new work or adding new connections. Concurrency with module-unload is handled by maintaining a module specific flag that is set at the start of the module exit function, and must be checked before enqueuing new work or adding new connections. This commit refactors existing RDS_DESTROY_PENDING checks added by commit 3db6e0d172c9 ("rds: use RCU to synchronize work-enqueue with connection teardown") and consolidates all the concurrency checks listed above into the function rds_destroy_pending(). Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-02-03 12:26:51 +00:00
if (rds_destroy_pending(cp->cp_conn)) {
rcu_read_unlock();
return;
}
if (rds_conn_path_state(cp) == RDS_CONN_DOWN &&
!test_and_set_bit(RDS_RECONNECT_PENDING, &cp->cp_flags))
queue_delayed_work(rds_wq, &cp->cp_conn_w, 0);
rcu_read_unlock();
}
RDS: TCP: Force every connection to be initiated by numerically smaller IP address When 2 RDS peers initiate an RDS-TCP connection simultaneously, there is a potential for "duelling syns" on either/both sides. See commit 241b271952eb ("RDS-TCP: Reset tcp callbacks if re-using an outgoing socket in rds_tcp_accept_one()") for a description of this condition, and the arbitration logic which ensures that the numerically large IP address in the TCP connection is bound to the RDS_TCP_PORT ("canonical ordering"). The rds_connection should not be marked as RDS_CONN_UP until the arbitration logic has converged for the following reason. The sender may start transmitting RDS datagrams as soon as RDS_CONN_UP is set, and since the sender removes all datagrams from the rds_connection's cp_retrans queue based on TCP acks. If the TCP ack was sent from a tcp socket that got reset as part of duel aribitration (but before data was delivered to the receivers RDS socket layer), the sender may end up prematurely freeing the datagram, and the datagram is no longer reliably deliverable. This patch remedies that condition by making sure that, upon receipt of 3WH completion state change notification of TCP_ESTABLISHED in rds_tcp_state_change, we mark the rds_connection as RDS_CONN_UP if, and only if, the IP addresses and ports for the connection are canonically ordered. In all other cases, rds_tcp_state_change will force an rds_conn_path_drop(), and rds_queue_reconnect() on both peers will restart the connection to ensure canonical ordering. A side-effect of enforcing this condition in rds_tcp_state_change() is that rds_tcp_accept_one_path() can now be refactored for simplicity. It is also no longer possible to encounter an RDS_CONN_UP connection in the arbitration logic in rds_tcp_accept_one(). Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-11-16 21:29:50 +00:00
EXPORT_SYMBOL_GPL(rds_conn_path_connect_if_down);
void rds_conn_connect_if_down(struct rds_connection *conn)
{
WARN_ON(conn->c_trans->t_mp_capable);
rds_conn_path_connect_if_down(&conn->c_path[0]);
}
EXPORT_SYMBOL_GPL(rds_conn_connect_if_down);
void
__rds_conn_path_error(struct rds_conn_path *cp, const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
vprintk(fmt, ap);
va_end(ap);
rds_conn_path_drop(cp, false);
}