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, 1 deletions

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 80d483864247..e9ebe9864cc4 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -908,7 +908,7 @@ void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async)
             !blk_mq_hw_queue_mapped(hctx)))
                 return;
 
-        if (!async) {
+        if (!async && !(hctx->flags & BLK_MQ_F_BLOCKING)) {
                 int cpu = get_cpu();
                 if (cpumask_test_cpu(cpu, hctx->cpumask)) {
                         __blk_mq_run_hw_queue(hctx);