linux/net/rxrpc/connection.c
Jesper Juhl ea2e90dfce [RXRPC]: Decrease number of pointer derefs in connection.c
Decrease the number of pointer derefs in net/rxrpc/connection.c

Benefits of the patch:
 - Fewer pointer dereferences should make the code slightly faster.
 - Size of generated code is smaller
 - improved readability

Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-10 13:07:44 -08:00

781 lines
20 KiB
C

/* connection.c: Rx connection routines
*
* Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <rxrpc/rxrpc.h>
#include <rxrpc/transport.h>
#include <rxrpc/peer.h>
#include <rxrpc/connection.h>
#include <rxrpc/call.h>
#include <rxrpc/message.h>
#include <linux/udp.h>
#include <linux/ip.h>
#include <net/sock.h>
#include <asm/uaccess.h>
#include "internal.h"
__RXACCT_DECL(atomic_t rxrpc_connection_count);
LIST_HEAD(rxrpc_conns);
DECLARE_RWSEM(rxrpc_conns_sem);
unsigned long rxrpc_conn_timeout = 60 * 60;
static void rxrpc_conn_do_timeout(struct rxrpc_connection *conn);
static void __rxrpc_conn_timeout(rxrpc_timer_t *timer)
{
struct rxrpc_connection *conn =
list_entry(timer, struct rxrpc_connection, timeout);
_debug("Rx CONN TIMEOUT [%p{u=%d}]", conn, atomic_read(&conn->usage));
rxrpc_conn_do_timeout(conn);
}
static const struct rxrpc_timer_ops rxrpc_conn_timer_ops = {
.timed_out = __rxrpc_conn_timeout,
};
/*****************************************************************************/
/*
* create a new connection record
*/
static inline int __rxrpc_create_connection(struct rxrpc_peer *peer,
struct rxrpc_connection **_conn)
{
struct rxrpc_connection *conn;
_enter("%p",peer);
/* allocate and initialise a connection record */
conn = kmalloc(sizeof(struct rxrpc_connection), GFP_KERNEL);
if (!conn) {
_leave(" = -ENOMEM");
return -ENOMEM;
}
memset(conn, 0, sizeof(struct rxrpc_connection));
atomic_set(&conn->usage, 1);
INIT_LIST_HEAD(&conn->link);
INIT_LIST_HEAD(&conn->id_link);
init_waitqueue_head(&conn->chanwait);
spin_lock_init(&conn->lock);
rxrpc_timer_init(&conn->timeout, &rxrpc_conn_timer_ops);
do_gettimeofday(&conn->atime);
conn->mtu_size = 1024;
conn->peer = peer;
conn->trans = peer->trans;
__RXACCT(atomic_inc(&rxrpc_connection_count));
*_conn = conn;
_leave(" = 0 (%p)", conn);
return 0;
} /* end __rxrpc_create_connection() */
/*****************************************************************************/
/*
* create a new connection record for outgoing connections
*/
int rxrpc_create_connection(struct rxrpc_transport *trans,
__be16 port,
__be32 addr,
uint16_t service_id,
void *security,
struct rxrpc_connection **_conn)
{
struct rxrpc_connection *candidate, *conn;
struct rxrpc_peer *peer;
struct list_head *_p;
__be32 connid;
int ret;
_enter("%p{%hu},%u,%hu", trans, trans->port, ntohs(port), service_id);
/* get a peer record */
ret = rxrpc_peer_lookup(trans, addr, &peer);
if (ret < 0) {
_leave(" = %d", ret);
return ret;
}
/* allocate and initialise a connection record */
ret = __rxrpc_create_connection(peer, &candidate);
if (ret < 0) {
rxrpc_put_peer(peer);
_leave(" = %d", ret);
return ret;
}
/* fill in the specific bits */
candidate->addr.sin_family = AF_INET;
candidate->addr.sin_port = port;
candidate->addr.sin_addr.s_addr = addr;
candidate->in_epoch = rxrpc_epoch;
candidate->out_epoch = rxrpc_epoch;
candidate->in_clientflag = 0;
candidate->out_clientflag = RXRPC_CLIENT_INITIATED;
candidate->service_id = htons(service_id);
/* invent a unique connection ID */
write_lock(&peer->conn_idlock);
try_next_id:
connid = htonl(peer->conn_idcounter & RXRPC_CIDMASK);
peer->conn_idcounter += RXRPC_MAXCALLS;
list_for_each(_p, &peer->conn_idlist) {
conn = list_entry(_p, struct rxrpc_connection, id_link);
if (connid == conn->conn_id)
goto try_next_id;
if (connid > conn->conn_id)
break;
}
_debug("selected candidate conn ID %x.%u",
ntohl(peer->addr.s_addr), ntohl(connid));
candidate->conn_id = connid;
list_add_tail(&candidate->id_link, _p);
write_unlock(&peer->conn_idlock);
/* attach to peer */
candidate->peer = peer;
write_lock(&peer->conn_lock);
/* search the peer's transport graveyard list */
spin_lock(&peer->conn_gylock);
list_for_each(_p, &peer->conn_graveyard) {
conn = list_entry(_p, struct rxrpc_connection, link);
if (conn->addr.sin_port == candidate->addr.sin_port &&
conn->security_ix == candidate->security_ix &&
conn->service_id == candidate->service_id &&
conn->in_clientflag == 0)
goto found_in_graveyard;
}
spin_unlock(&peer->conn_gylock);
/* pick the new candidate */
_debug("created connection: {%08x} [out]", ntohl(candidate->conn_id));
atomic_inc(&peer->conn_count);
conn = candidate;
candidate = NULL;
make_active:
list_add_tail(&conn->link, &peer->conn_active);
write_unlock(&peer->conn_lock);
if (candidate) {
write_lock(&peer->conn_idlock);
list_del(&candidate->id_link);
write_unlock(&peer->conn_idlock);
__RXACCT(atomic_dec(&rxrpc_connection_count));
kfree(candidate);
}
else {
down_write(&rxrpc_conns_sem);
list_add_tail(&conn->proc_link, &rxrpc_conns);
up_write(&rxrpc_conns_sem);
}
*_conn = conn;
_leave(" = 0 (%p)", conn);
return 0;
/* handle resurrecting a connection from the graveyard */
found_in_graveyard:
_debug("resurrecting connection: {%08x} [out]", ntohl(conn->conn_id));
rxrpc_get_connection(conn);
rxrpc_krxtimod_del_timer(&conn->timeout);
list_del_init(&conn->link);
spin_unlock(&peer->conn_gylock);
goto make_active;
} /* end rxrpc_create_connection() */
/*****************************************************************************/
/*
* lookup the connection for an incoming packet
* - create a new connection record for unrecorded incoming connections
*/
int rxrpc_connection_lookup(struct rxrpc_peer *peer,
struct rxrpc_message *msg,
struct rxrpc_connection **_conn)
{
struct rxrpc_connection *conn, *candidate = NULL;
struct list_head *_p;
struct sk_buff *pkt = msg->pkt;
int ret, fresh = 0;
__be32 x_epoch, x_connid;
__be16 x_port, x_servid;
__u32 x_secix;
u8 x_clflag;
_enter("%p{{%hu}},%u,%hu",
peer,
peer->trans->port,
ntohs(pkt->h.uh->source),
ntohs(msg->hdr.serviceId));
x_port = pkt->h.uh->source;
x_epoch = msg->hdr.epoch;
x_clflag = msg->hdr.flags & RXRPC_CLIENT_INITIATED;
x_connid = htonl(ntohl(msg->hdr.cid) & RXRPC_CIDMASK);
x_servid = msg->hdr.serviceId;
x_secix = msg->hdr.securityIndex;
/* [common case] search the transport's active list first */
read_lock(&peer->conn_lock);
list_for_each(_p, &peer->conn_active) {
conn = list_entry(_p, struct rxrpc_connection, link);
if (conn->addr.sin_port == x_port &&
conn->in_epoch == x_epoch &&
conn->conn_id == x_connid &&
conn->security_ix == x_secix &&
conn->service_id == x_servid &&
conn->in_clientflag == x_clflag)
goto found_active;
}
read_unlock(&peer->conn_lock);
/* [uncommon case] not active
* - create a candidate for a new record if an inbound connection
* - only examine the graveyard for an outbound connection
*/
if (x_clflag) {
ret = __rxrpc_create_connection(peer, &candidate);
if (ret < 0) {
_leave(" = %d", ret);
return ret;
}
/* fill in the specifics */
candidate->addr.sin_family = AF_INET;
candidate->addr.sin_port = x_port;
candidate->addr.sin_addr.s_addr = pkt->nh.iph->saddr;
candidate->in_epoch = x_epoch;
candidate->out_epoch = x_epoch;
candidate->in_clientflag = RXRPC_CLIENT_INITIATED;
candidate->out_clientflag = 0;
candidate->conn_id = x_connid;
candidate->service_id = x_servid;
candidate->security_ix = x_secix;
}
/* search the active list again, just in case it appeared whilst we
* were busy */
write_lock(&peer->conn_lock);
list_for_each(_p, &peer->conn_active) {
conn = list_entry(_p, struct rxrpc_connection, link);
if (conn->addr.sin_port == x_port &&
conn->in_epoch == x_epoch &&
conn->conn_id == x_connid &&
conn->security_ix == x_secix &&
conn->service_id == x_servid &&
conn->in_clientflag == x_clflag)
goto found_active_second_chance;
}
/* search the transport's graveyard list */
spin_lock(&peer->conn_gylock);
list_for_each(_p, &peer->conn_graveyard) {
conn = list_entry(_p, struct rxrpc_connection, link);
if (conn->addr.sin_port == x_port &&
conn->in_epoch == x_epoch &&
conn->conn_id == x_connid &&
conn->security_ix == x_secix &&
conn->service_id == x_servid &&
conn->in_clientflag == x_clflag)
goto found_in_graveyard;
}
spin_unlock(&peer->conn_gylock);
/* outbound connections aren't created here */
if (!x_clflag) {
write_unlock(&peer->conn_lock);
_leave(" = -ENOENT");
return -ENOENT;
}
/* we can now add the new candidate to the list */
_debug("created connection: {%08x} [in]", ntohl(candidate->conn_id));
rxrpc_get_peer(peer);
conn = candidate;
candidate = NULL;
atomic_inc(&peer->conn_count);
fresh = 1;
make_active:
list_add_tail(&conn->link, &peer->conn_active);
success_uwfree:
write_unlock(&peer->conn_lock);
if (candidate) {
write_lock(&peer->conn_idlock);
list_del(&candidate->id_link);
write_unlock(&peer->conn_idlock);
__RXACCT(atomic_dec(&rxrpc_connection_count));
kfree(candidate);
}
if (fresh) {
down_write(&rxrpc_conns_sem);
list_add_tail(&conn->proc_link, &rxrpc_conns);
up_write(&rxrpc_conns_sem);
}
success:
*_conn = conn;
_leave(" = 0 (%p)", conn);
return 0;
/* handle the connection being found in the active list straight off */
found_active:
rxrpc_get_connection(conn);
read_unlock(&peer->conn_lock);
goto success;
/* handle resurrecting a connection from the graveyard */
found_in_graveyard:
_debug("resurrecting connection: {%08x} [in]", ntohl(conn->conn_id));
rxrpc_get_peer(peer);
rxrpc_get_connection(conn);
rxrpc_krxtimod_del_timer(&conn->timeout);
list_del_init(&conn->link);
spin_unlock(&peer->conn_gylock);
goto make_active;
/* handle finding the connection on the second time through the active
* list */
found_active_second_chance:
rxrpc_get_connection(conn);
goto success_uwfree;
} /* end rxrpc_connection_lookup() */
/*****************************************************************************/
/*
* finish using a connection record
* - it will be transferred to the peer's connection graveyard when refcount
* reaches 0
*/
void rxrpc_put_connection(struct rxrpc_connection *conn)
{
struct rxrpc_peer *peer;
if (!conn)
return;
_enter("%p{u=%d p=%hu}",
conn, atomic_read(&conn->usage), ntohs(conn->addr.sin_port));
peer = conn->peer;
spin_lock(&peer->conn_gylock);
/* sanity check */
if (atomic_read(&conn->usage) <= 0)
BUG();
if (likely(!atomic_dec_and_test(&conn->usage))) {
spin_unlock(&peer->conn_gylock);
_leave("");
return;
}
/* move to graveyard queue */
_debug("burying connection: {%08x}", ntohl(conn->conn_id));
list_del(&conn->link);
list_add_tail(&conn->link, &peer->conn_graveyard);
rxrpc_krxtimod_add_timer(&conn->timeout, rxrpc_conn_timeout * HZ);
spin_unlock(&peer->conn_gylock);
rxrpc_put_peer(conn->peer);
_leave(" [killed]");
} /* end rxrpc_put_connection() */
/*****************************************************************************/
/*
* free a connection record
*/
static void rxrpc_conn_do_timeout(struct rxrpc_connection *conn)
{
struct rxrpc_peer *peer;
_enter("%p{u=%d p=%hu}",
conn, atomic_read(&conn->usage), ntohs(conn->addr.sin_port));
peer = conn->peer;
if (atomic_read(&conn->usage) < 0)
BUG();
/* remove from graveyard if still dead */
spin_lock(&peer->conn_gylock);
if (atomic_read(&conn->usage) == 0) {
list_del_init(&conn->link);
}
else {
conn = NULL;
}
spin_unlock(&peer->conn_gylock);
if (!conn) {
_leave("");
return; /* resurrected */
}
_debug("--- Destroying Connection %p{%08x} ---",
conn, ntohl(conn->conn_id));
down_write(&rxrpc_conns_sem);
list_del(&conn->proc_link);
up_write(&rxrpc_conns_sem);
write_lock(&peer->conn_idlock);
list_del(&conn->id_link);
write_unlock(&peer->conn_idlock);
__RXACCT(atomic_dec(&rxrpc_connection_count));
kfree(conn);
/* if the graveyard is now empty, wake up anyone waiting for that */
if (atomic_dec_and_test(&peer->conn_count))
wake_up(&peer->conn_gy_waitq);
_leave(" [destroyed]");
} /* end rxrpc_conn_do_timeout() */
/*****************************************************************************/
/*
* clear all connection records from a peer endpoint
*/
void rxrpc_conn_clearall(struct rxrpc_peer *peer)
{
DECLARE_WAITQUEUE(myself, current);
struct rxrpc_connection *conn;
int err;
_enter("%p", peer);
/* there shouldn't be any active conns remaining */
if (!list_empty(&peer->conn_active))
BUG();
/* manually timeout all conns in the graveyard */
spin_lock(&peer->conn_gylock);
while (!list_empty(&peer->conn_graveyard)) {
conn = list_entry(peer->conn_graveyard.next,
struct rxrpc_connection, link);
err = rxrpc_krxtimod_del_timer(&conn->timeout);
spin_unlock(&peer->conn_gylock);
if (err == 0)
rxrpc_conn_do_timeout(conn);
spin_lock(&peer->conn_gylock);
}
spin_unlock(&peer->conn_gylock);
/* wait for the the conn graveyard to be completely cleared */
set_current_state(TASK_UNINTERRUPTIBLE);
add_wait_queue(&peer->conn_gy_waitq, &myself);
while (atomic_read(&peer->conn_count) != 0) {
schedule();
set_current_state(TASK_UNINTERRUPTIBLE);
}
remove_wait_queue(&peer->conn_gy_waitq, &myself);
set_current_state(TASK_RUNNING);
_leave("");
} /* end rxrpc_conn_clearall() */
/*****************************************************************************/
/*
* allocate and prepare a message for sending out through the transport
* endpoint
*/
int rxrpc_conn_newmsg(struct rxrpc_connection *conn,
struct rxrpc_call *call,
uint8_t type,
int dcount,
struct kvec diov[],
gfp_t alloc_flags,
struct rxrpc_message **_msg)
{
struct rxrpc_message *msg;
int loop;
_enter("%p{%d},%p,%u", conn, ntohs(conn->addr.sin_port), call, type);
if (dcount > 3) {
_leave(" = -EINVAL");
return -EINVAL;
}
msg = kmalloc(sizeof(struct rxrpc_message), alloc_flags);
if (!msg) {
_leave(" = -ENOMEM");
return -ENOMEM;
}
memset(msg, 0, sizeof(*msg));
atomic_set(&msg->usage, 1);
INIT_LIST_HEAD(&msg->link);
msg->state = RXRPC_MSG_PREPARED;
msg->hdr.epoch = conn->out_epoch;
msg->hdr.cid = conn->conn_id | (call ? call->chan_ix : 0);
msg->hdr.callNumber = call ? call->call_id : 0;
msg->hdr.type = type;
msg->hdr.flags = conn->out_clientflag;
msg->hdr.securityIndex = conn->security_ix;
msg->hdr.serviceId = conn->service_id;
/* generate sequence numbers for data packets */
if (call) {
switch (type) {
case RXRPC_PACKET_TYPE_DATA:
msg->seq = ++call->snd_seq_count;
msg->hdr.seq = htonl(msg->seq);
break;
case RXRPC_PACKET_TYPE_ACK:
/* ACK sequence numbers are complicated. The following
* may be wrong:
* - jumbo packet ACKs should have a seq number
* - normal ACKs should not
*/
default:
break;
}
}
msg->dcount = dcount + 1;
msg->dsize = sizeof(msg->hdr);
msg->data[0].iov_len = sizeof(msg->hdr);
msg->data[0].iov_base = &msg->hdr;
for (loop=0; loop < dcount; loop++) {
msg->dsize += diov[loop].iov_len;
msg->data[loop+1].iov_len = diov[loop].iov_len;
msg->data[loop+1].iov_base = diov[loop].iov_base;
}
__RXACCT(atomic_inc(&rxrpc_message_count));
*_msg = msg;
_leave(" = 0 (%p) #%d", msg, atomic_read(&rxrpc_message_count));
return 0;
} /* end rxrpc_conn_newmsg() */
/*****************************************************************************/
/*
* free a message
*/
void __rxrpc_put_message(struct rxrpc_message *msg)
{
int loop;
_enter("%p #%d", msg, atomic_read(&rxrpc_message_count));
if (msg->pkt)
kfree_skb(msg->pkt);
rxrpc_put_connection(msg->conn);
for (loop = 0; loop < 8; loop++)
if (test_bit(loop, &msg->dfree))
kfree(msg->data[loop].iov_base);
__RXACCT(atomic_dec(&rxrpc_message_count));
kfree(msg);
_leave("");
} /* end __rxrpc_put_message() */
/*****************************************************************************/
/*
* send a message out through the transport endpoint
*/
int rxrpc_conn_sendmsg(struct rxrpc_connection *conn,
struct rxrpc_message *msg)
{
struct msghdr msghdr;
int ret;
_enter("%p{%d}", conn, ntohs(conn->addr.sin_port));
/* fill in some fields in the header */
spin_lock(&conn->lock);
msg->hdr.serial = htonl(++conn->serial_counter);
msg->rttdone = 0;
spin_unlock(&conn->lock);
/* set up the message to be transmitted */
msghdr.msg_name = &conn->addr;
msghdr.msg_namelen = sizeof(conn->addr);
msghdr.msg_control = NULL;
msghdr.msg_controllen = 0;
msghdr.msg_flags = MSG_CONFIRM | MSG_DONTWAIT;
_net("Sending message type %d of %Zd bytes to %08x:%d",
msg->hdr.type,
msg->dsize,
ntohl(conn->addr.sin_addr.s_addr),
ntohs(conn->addr.sin_port));
/* send the message */
ret = kernel_sendmsg(conn->trans->socket, &msghdr,
msg->data, msg->dcount, msg->dsize);
if (ret < 0) {
msg->state = RXRPC_MSG_ERROR;
} else {
msg->state = RXRPC_MSG_SENT;
ret = 0;
spin_lock(&conn->lock);
do_gettimeofday(&conn->atime);
msg->stamp = conn->atime;
spin_unlock(&conn->lock);
}
_leave(" = %d", ret);
return ret;
} /* end rxrpc_conn_sendmsg() */
/*****************************************************************************/
/*
* deal with a subsequent call packet
*/
int rxrpc_conn_receive_call_packet(struct rxrpc_connection *conn,
struct rxrpc_call *call,
struct rxrpc_message *msg)
{
struct rxrpc_message *pmsg;
struct dst_entry *dst;
struct list_head *_p;
unsigned cix, seq;
int ret = 0;
_enter("%p,%p,%p", conn, call, msg);
if (!call) {
cix = ntohl(msg->hdr.cid) & RXRPC_CHANNELMASK;
spin_lock(&conn->lock);
call = conn->channels[cix];
if (!call || call->call_id != msg->hdr.callNumber) {
spin_unlock(&conn->lock);
rxrpc_trans_immediate_abort(conn->trans, msg, -ENOENT);
goto out;
}
else {
rxrpc_get_call(call);
spin_unlock(&conn->lock);
}
}
else {
rxrpc_get_call(call);
}
_proto("Received packet %%%u [%u] on call %hu:%u:%u",
ntohl(msg->hdr.serial),
ntohl(msg->hdr.seq),
ntohs(msg->hdr.serviceId),
ntohl(conn->conn_id),
ntohl(call->call_id));
call->pkt_rcv_count++;
dst = msg->pkt->dst;
if (dst && dst->dev)
conn->peer->if_mtu =
dst->dev->mtu - dst->dev->hard_header_len;
/* queue on the call in seq order */
rxrpc_get_message(msg);
seq = msg->seq;
spin_lock(&call->lock);
list_for_each(_p, &call->rcv_receiveq) {
pmsg = list_entry(_p, struct rxrpc_message, link);
if (pmsg->seq > seq)
break;
}
list_add_tail(&msg->link, _p);
/* reset the activity timeout */
call->flags |= RXRPC_CALL_RCV_PKT;
mod_timer(&call->rcv_timeout,jiffies + rxrpc_call_rcv_timeout * HZ);
spin_unlock(&call->lock);
rxrpc_krxiod_queue_call(call);
rxrpc_put_call(call);
out:
_leave(" = %d", ret);
return ret;
} /* end rxrpc_conn_receive_call_packet() */
/*****************************************************************************/
/*
* handle an ICMP error being applied to a connection
*/
void rxrpc_conn_handle_error(struct rxrpc_connection *conn,
int local, int errno)
{
struct rxrpc_call *calls[4];
int loop;
_enter("%p{%d},%d", conn, ntohs(conn->addr.sin_port), errno);
/* get a ref to all my calls in one go */
memset(calls, 0, sizeof(calls));
spin_lock(&conn->lock);
for (loop = 3; loop >= 0; loop--) {
if (conn->channels[loop]) {
calls[loop] = conn->channels[loop];
rxrpc_get_call(calls[loop]);
}
}
spin_unlock(&conn->lock);
/* now kick them all */
for (loop = 3; loop >= 0; loop--) {
if (calls[loop]) {
rxrpc_call_handle_error(calls[loop], local, errno);
rxrpc_put_call(calls[loop]);
}
}
_leave("");
} /* end rxrpc_conn_handle_error() */