| From: Andrea Parri <andrea.parri@amarulasolutions.com> |
| Date: Mon, 20 May 2019 19:23:57 +0200 |
| Subject: sbitmap: fix improper use of smp_mb__before_atomic() |
| |
| 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@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> |
| [bwh: Backported to 3.16: adjust filename] |
| Signed-off-by: Ben Hutchings <ben@decadent.org.uk> |
| --- |
| 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); |
| } |
