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sbitmap: fix improper use of smp_mb__before_atomic() 

commit a0934fd2b1 upstream.

This barrier only applies to the read-modify-write operations; in
particular, it does not apply to the atomic_set() primitive.

Replace the barrier with an smp_mb().

Fixes: 6c0ca7ae29 ("sbitmap: fix wakeup hang after sbq resize")
Cc: stable@vger.kernel.org
Reported-by: "Paul E. McKenney" <paulmck@linux.ibm.com>
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrea Parri <andrea.parri@amarulasolutions.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Omar Sandoval <osandov@fb.com>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: linux-block@vger.kernel.org
Cc: "Paul E. McKenney" <paulmck@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Andrea Parri 2019-05-20 19:23:57 +02:00 committed by Greg Kroah-Hartman
parent f0b882dd9e
commit fce095450b
1 changed files with 1 additions and 1 deletions
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2
lib/sbitmap.c
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@ -338,7 +338,7 @@ void sbitmap_queue_resize(struct sbitmap_queue *sbq, unsigned int depth)
* Pairs with the memory barrier in sbq_wake_up() to ensure that
* the batch size is updated before the wait counts.
*/
smp_mb__before_atomic();
smp_mb();
for (i = 0; i < SBQ_WAIT_QUEUES; i++)
atomic_set(&sbq->ws[i].wait_cnt, 1);
}