tipc: improve function tipc_wait_for_rcvmsg()

This commit replaces schedule_timeout() with wait_woken()
in function tipc_wait_for_rcvmsg(). wait_woken() uses
memory barriers in its implementation to avoid potential
race condition when putting a process into sleeping state
and then waking it up.

Acked-by: Ying Xue <ying.xue@windriver.com>
Acked-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: Tung Nguyen <tung.q.nguyen@dektech.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 4 deletions

diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 81b87916a0eb..684f2125fc6b 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -1677,7 +1677,7 @@ static void tipc_sk_send_ack(struct tipc_sock *tsk)
 static int tipc_wait_for_rcvmsg(struct socket *sock, long *timeop)
 {
         struct sock *sk = sock->sk;
-        DEFINE_WAIT(wait);
+        DEFINE_WAIT_FUNC(wait, woken_wake_function);
         long timeo = *timeop;
         int err = sock_error(sk);
 
@@ -1685,15 +1685,17 @@ static int tipc_wait_for_rcvmsg(struct socket *sock, long *timeop)
                 return err;
 
         for (;;) {
-                prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
                 if (timeo && skb_queue_empty(&sk->sk_receive_queue)) {
                         if (sk->sk_shutdown & RCV_SHUTDOWN) {
                                 err = -ENOTCONN;
                                 break;
                         }
+                        add_wait_queue(sk_sleep(sk), &wait);
                         release_sock(sk);
-                        timeo = schedule_timeout(timeo);
+                        timeo = wait_woken(&wait, TASK_INTERRUPTIBLE, timeo);
+                        sched_annotate_sleep();
                         lock_sock(sk);
+                        remove_wait_queue(sk_sleep(sk), &wait);
                 }
                 err = 0;
                 if (!skb_queue_empty(&sk->sk_receive_queue))
@@ -1709,7 +1711,6 @@ static int tipc_wait_for_rcvmsg(struct socket *sock, long *timeop)
                 if (err)
                         break;
         }
-        finish_wait(sk_sleep(sk), &wait);
         *timeop = timeo;
         return err;
 }