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* [PATCH 2/4] bio: fix improper use of smp_mb__before_atomic()
       [not found] <1558373038-5611-1-git-send-email-andrea.parri@amarulasolutions.com>
@ 2019-05-20 17:23 ` Andrea Parri
  2019-05-20 17:23 ` [PATCH 3/4] sbitmap: " Andrea Parri
  1 sibling, 0 replies; 2+ messages in thread
From: Andrea Parri @ 2019-05-20 17:23 UTC (permalink / raw)
  To: linux-kernel
  Cc: Andrea Parri, stable, Jens Axboe, Ming Lei, linux-block,
	Paul E. McKenney, Peter Zijlstra

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: dac56212e8127 ("bio: skip atomic inc/dec of ->bi_cnt for most use cases")
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: 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>
---
 include/linux/bio.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/bio.h b/include/linux/bio.h
index ea73df36529ad..0f23b56826403 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -210,7 +210,7 @@ static inline void bio_cnt_set(struct bio *bio, unsigned int count)
 {
 	if (count != 1) {
 		bio->bi_flags |= (1 << BIO_REFFED);
-		smp_mb__before_atomic();
+		smp_mb();
 	}
 	atomic_set(&bio->__bi_cnt, count);
 }
-- 
2.7.4


^ permalink raw reply	[flat|nested] 2+ messages in thread

* [PATCH 3/4] sbitmap: fix improper use of smp_mb__before_atomic()
       [not found] <1558373038-5611-1-git-send-email-andrea.parri@amarulasolutions.com>
  2019-05-20 17:23 ` [PATCH 2/4] bio: fix improper use of smp_mb__before_atomic() Andrea Parri
@ 2019-05-20 17:23 ` " Andrea Parri
  1 sibling, 0 replies; 2+ messages in thread
From: Andrea Parri @ 2019-05-20 17:23 UTC (permalink / raw)
  To: linux-kernel
  Cc: Andrea Parri, stable, Jens Axboe, Omar Sandoval, Ming Lei,
	linux-block, Paul E. McKenney, Peter Zijlstra

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: 6c0ca7ae292ad ("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>
---
 lib/sbitmap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/sbitmap.c b/lib/sbitmap.c
index 155fe38756ecf..4a7fc4915dfc6 100644
--- a/lib/sbitmap.c
+++ b/lib/sbitmap.c
@@ -435,7 +435,7 @@ static void sbitmap_queue_update_wake_batch(struct sbitmap_queue *sbq,
 		 * 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);
 	}
-- 
2.7.4


^ permalink raw reply	[flat|nested] 2+ messages in thread

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2019-05-20 17:23 ` [PATCH 2/4] bio: fix improper use of smp_mb__before_atomic() Andrea Parri
2019-05-20 17:23 ` [PATCH 3/4] sbitmap: " Andrea Parri

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