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rds: add missing barrier to release_refill

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The functions clear_bit and set_bit do not imply a memory barrier, thus it
may be possible that the waitqueue_active function (which does not take
any locks) is moved before clear_bit and it could miss a wakeup event.

Fix this bug by adding a memory barrier after clear_bit.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Mikulas Patocka 2022-08-10 09:00:42 -04:00 committed by David S. Miller
parent 7ebfc85e2c
commit 9f414eb409
1 changed files with 1 additions and 0 deletions
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net/rds/ib_recv.c
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@ -363,6 +363,7 @@ static int acquire_refill(struct rds_connection *conn)
static void release_refill(struct rds_connection *conn) static void release_refill(struct rds_connection *conn)
{ {
clear_bit(RDS_RECV_REFILL, &conn->c_flags); clear_bit(RDS_RECV_REFILL, &conn->c_flags);
smp_mb__after_atomic();
/* We don't use wait_on_bit()/wake_up_bit() because our waking is in a /* We don't use wait_on_bit()/wake_up_bit() because our waking is in a
* hot path and finding waiters is very rare. We don't want to walk * hot path and finding waiters is very rare. We don't want to walk