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-rw-r--r--net/ipv4/tcp.c4
-rw-r--r--net/ipv4/tcp_input.c2
2 files changed, 5 insertions, 1 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 59c8a027721b..8c5cd9efebbc 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -520,8 +520,10 @@ unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
/* Race breaker. If space is freed after
* wspace test but before the flags are set,
- * IO signal will be lost.
+ * IO signal will be lost. Memory barrier
+ * pairs with the input side.
*/
+ smp_mb__after_atomic();
if (sk_stream_is_writeable(sk))
mask |= POLLOUT | POLLWRNORM;
}
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index a7ef679dd3ea..3a4d9b34bed4 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -4845,6 +4845,8 @@ static void tcp_check_space(struct sock *sk)
{
if (sock_flag(sk, SOCK_QUEUE_SHRUNK)) {
sock_reset_flag(sk, SOCK_QUEUE_SHRUNK);
+ /* pairs with tcp_poll() */
+ smp_mb__after_atomic();
if (sk->sk_socket &&
test_bit(SOCK_NOSPACE, &sk->sk_socket->flags))
tcp_new_space(sk);