block: make queue flags non-atomic

We can save some atomic ops in the IO path, if we clearly define
the rules of how to modify the queue flags.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 87620b705bee..acd716b657b8 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -282,7 +282,8 @@ static mddev_t * mddev_find(dev_t unit)
                 kfree(new);
                 return NULL;
         }
-        set_bit(QUEUE_FLAG_CLUSTER, &new->queue->queue_flags);
+        /* Can be unlocked because the queue is new: no concurrency */
+        queue_flag_set_unlocked(QUEUE_FLAG_CLUSTER, new->queue);
 
         blk_queue_make_request(new->queue, md_fail_request);