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tcp: correct memory barrier usage in tcp_check_space()

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[ Upstream commit 56d806222ace4c3aeae516cd7a855340fb2839d8 ]

sock_reset_flag() maps to __clear_bit() not the atomic version clear_bit().
Thus, we need smp_mb(), smp_mb__after_atomic() is not sufficient.

Fixes: 3c7151275c0c ("tcp: add memory barriers to write space paths")
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Jason Baron <jbaron@akamai.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Reported-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jason Baron 2017-01-24 21:49:41 -05:00 committed by Greg Kroah-Hartman
parent bc42f67b73
commit 1b7dbabf02
1 changed files with 1 additions and 1 deletions
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2
net/ipv4/tcp_input.c
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@ -4942,7 +4942,7 @@ 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();
smp_mb();
if (sk->sk_socket &&
test_bit(SOCK_NOSPACE, &sk->sk_socket->flags))
tcp_new_space(sk);