blk-mq: don't run might_sleep() if the operation needn't blocking

The operation protected via blk_mq_run_dispatch_ops() in blk_mq_run_hw_queue
won't sleep, so don't run might_sleep() for it.

Reported-and-tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 22ec21aa0c22cf1f4c61605183c1267aa7a346c8..706e9a836fe685a7939f70bae622f3f3d553844d 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2048,7 +2048,7 @@ void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async)
         * And queue will be rerun in blk_mq_unquiesce_queue() if it is
         * quiesced.
         */
-       blk_mq_run_dispatch_ops(hctx->queue,
+       __blk_mq_run_dispatch_ops(hctx->queue, false,
                need_run = !blk_queue_quiesced(hctx->queue) &&
                blk_mq_hctx_has_pending(hctx));
 

diff --git a/block/blk-mq.h b/block/blk-mq.h
index d62004e2d531cd3ef3a0005fe942d039fd0ba1ad..948791ea2a3e8d20a3182d18a86d713e244775eb 100644 (file)
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -375,7 +375,7 @@ static inline bool hctx_may_queue(struct blk_mq_hw_ctx *hctx,
 }
 
 /* run the code block in @dispatch_ops with rcu/srcu read lock held */
-#define blk_mq_run_dispatch_ops(q, dispatch_ops)               \
+#define __blk_mq_run_dispatch_ops(q, check_sleep, dispatch_ops)        \
 do {                                                           \
        if (!blk_queue_has_srcu(q)) {                           \
                rcu_read_lock();                                \
@@ -384,11 +384,14 @@ do {                                                              \
        } else {                                                \
                int srcu_idx;                                   \
                                                                \
-               might_sleep();                                  \
+               might_sleep_if(check_sleep);                    \
                srcu_idx = srcu_read_lock((q)->srcu);           \
                (dispatch_ops);                                 \
                srcu_read_unlock((q)->srcu, srcu_idx);          \
        }                                                       \
 } while (0)
 
+#define blk_mq_run_dispatch_ops(q, dispatch_ops)               \
+       __blk_mq_run_dispatch_ops(q, true, dispatch_ops)        \
+
 #endif