3.16.75-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Andrea Parri <andrea.parri@xxxxxxxxxxxxxxxxxxxx>
commit a0934fd2b1208458e55fc4b48f55889809fce666 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: 6c0ca7ae292ad ("sbitmap: fix wakeup hang after sbq resize")
Reported-by: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxx>
Reported-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Signed-off-by: Andrea Parri <andrea.parri@xxxxxxxxxxxxxxxxxxxx>
Reviewed-by: Ming Lei <ming.lei@xxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: Omar Sandoval <osandov@xxxxxx>
Cc: Ming Lei <ming.lei@xxxxxxxxxx>
Cc: linux-block@xxxxxxxxxxxxxxx
Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
[bwh: Backported to 3.16: adjust filename]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
block/blk-mq-tag.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -499,7 +499,7 @@ static void bt_update_count(struct blk_m
* Pairs with the memory barrier in bt_clear_tag() to ensure
* that the batch size is updated before the wait counts.
*/
- smp_mb__before_atomic();
+ smp_mb();
for (i = 0; i < BT_WAIT_QUEUES; i++)
atomic_set(&bt->bs[i].wait_cnt, 1);
}
