3.16.75-rc1 review patch. If anyone has any objections, please let me know.
------------------ From: Andrea Parri <[email protected]> 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" <[email protected]> Reported-by: Peter Zijlstra <[email protected]> Signed-off-by: Andrea Parri <[email protected]> Reviewed-by: Ming Lei <[email protected]> Cc: Jens Axboe <[email protected]> Cc: Omar Sandoval <[email protected]> Cc: Ming Lei <[email protected]> Cc: [email protected] Cc: "Paul E. McKenney" <[email protected]> Cc: Peter Zijlstra <[email protected]> Signed-off-by: Jens Axboe <[email protected]> [bwh: Backported to 3.16: adjust filename] Signed-off-by: Ben Hutchings <[email protected]> --- 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); }
