From 3f40504f7ee419eda0068e55e0ee2622e1fce40b Mon Sep 17 00:00:00 2001 From: Ying Xue Date: Fri, 17 Jan 2014 09:50:05 +0800 Subject: [PATCH] tipc: standardize sendmsg routine of connectionless socket Comparing the behaviour of how to wait for events in TIPC sendmsg() with other stacks, the TIPC implementation might be perceived as different, and sometimes even incorrect. For instance, sk_sleep() and tport->congested variables associated with socket are exposed without socket lock protection while wait_event_interruptible_timeout() accesses them. So standardizing it with similar implementation in other stacks can help us correct these errors which the process of calling sendmsg() cannot be woken up event if an expected event arrive at socket or improperly woken up although the wake condition doesn't match. Signed-off-by: Ying Xue Reviewed-by: Jon Maloy Signed-off-by: David S. Miller --- net/tipc/socket.c | 39 +++++++++++++++++++++++++++++---------- 1 file changed, 29 insertions(+), 10 deletions(-) diff --git a/net/tipc/socket.c b/net/tipc/socket.c index 008f6fdf95c3..3e019737e4b3 100644 --- a/net/tipc/socket.c +++ b/net/tipc/socket.c @@ -567,6 +567,31 @@ static int dest_name_check(struct sockaddr_tipc *dest, struct msghdr *m) return 0; } +static int tipc_wait_for_sndmsg(struct socket *sock, long *timeo_p) +{ + struct sock *sk = sock->sk; + struct tipc_port *tport = tipc_sk_port(sk); + DEFINE_WAIT(wait); + int done; + + do { + int err = sock_error(sk); + if (err) + return err; + if (sock->state == SS_DISCONNECTING) + return -EPIPE; + if (!*timeo_p) + return -EAGAIN; + if (signal_pending(current)) + return sock_intr_errno(*timeo_p); + + prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE); + done = sk_wait_event(sk, timeo_p, !tport->congested); + finish_wait(sk_sleep(sk), &wait); + } while (!done); + return 0; +} + /** * send_msg - send message in connectionless manner * @iocb: if NULL, indicates that socket lock is already held @@ -588,7 +613,7 @@ static int send_msg(struct kiocb *iocb, struct socket *sock, struct tipc_port *tport = tipc_sk_port(sk); struct sockaddr_tipc *dest = (struct sockaddr_tipc *)m->msg_name; int needs_conn; - long timeout_val; + long timeo; int res = -EINVAL; if (unlikely(!dest)) @@ -625,8 +650,7 @@ static int send_msg(struct kiocb *iocb, struct socket *sock, reject_rx_queue(sk); } - timeout_val = sock_sndtimeo(sk, m->msg_flags & MSG_DONTWAIT); - + timeo = sock_sndtimeo(sk, m->msg_flags & MSG_DONTWAIT); do { if (dest->addrtype == TIPC_ADDR_NAME) { res = dest_name_check(dest, m); @@ -660,14 +684,9 @@ static int send_msg(struct kiocb *iocb, struct socket *sock, sock->state = SS_CONNECTING; break; } - if (timeout_val <= 0L) { - res = timeout_val ? timeout_val : -EWOULDBLOCK; + res = tipc_wait_for_sndmsg(sock, &timeo); + if (res) break; - } - release_sock(sk); - timeout_val = wait_event_interruptible_timeout(*sk_sleep(sk), - !tport->congested, timeout_val); - lock_sock(sk); } while (1); exit: