blk-mq: add flag for drivers wanting blocking ->queue_rq()

If a driver sets BLK_MQ_F_BLOCKING, it is allowed to block in its
->queue_rq() handler. For that case, blk-mq ensures that we always
calls it from a safe context.

Signed-off-by: Jens Axboe <axboe@fb.com>
Tested-by: Josef Bacik <jbacik@fb.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index fbcfdf323243..5daa0ef756dd 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -155,6 +155,7 @@ enum {
         BLK_MQ_F_TAG_SHARED     = 1 << 1,
         BLK_MQ_F_SG_MERGE       = 1 << 2,
         BLK_MQ_F_DEFER_ISSUE    = 1 << 4,
+        BLK_MQ_F_BLOCKING       = 1 << 5,
         BLK_MQ_F_ALLOC_POLICY_START_BIT = 8,
         BLK_MQ_F_ALLOC_POLICY_BITS = 1,