blk-mq: Warn when attempting to run a hardware queue that is not mapped

A queue must be frozen while the mapped state of a hardware queue is changed. Additionally, any change of the mapped state is followed by a call to blk_mq_map_swqueue() (see also blk_mq_init_allocated_queue() and blk_mq_update_nr_hw_queues()). Since blk_mq_map_swqueue() does not map any unmapped hardware queue onto any software queue, no attempt will be made to run an unmapped hardware queue. Hence issue a warning upon attempts to run an unmapped hardware queue. Signed-off-by: Bart Van Assche <[email protected]> Reviewed-by: Christoph Hellwig <[email protected]> Cc: Hannes Reinecke <[email protected]> Cc: Omar Sandoval <[email protected]> Cc: Ming Lei <[email protected]> Signed-off-by: Jens Axboe <[email protected]>
modi0012 · Jun 21, 2017 · 5435c02 · 5435c02
1 parent edf8ff5
commit 5435c02
Showing 1 changed file with 5 additions and 3 deletions.
diff --git a/block/blk-mq.c b/block/blk-mq.c
@@ -1129,8 +1129,10 @@ static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx *hctx)
 static void __blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async,
 					unsigned long msecs)
 {
-	if (unlikely(blk_mq_hctx_stopped(hctx) ||
-		     !blk_mq_hw_queue_mapped(hctx)))
+	if (WARN_ON_ONCE(!blk_mq_hw_queue_mapped(hctx)))
+		return;
+
+	if (unlikely(blk_mq_hctx_stopped(hctx)))
 		return;
 
 	if (!async && !(hctx->flags & BLK_MQ_F_BLOCKING)) {
@@ -1295,7 +1297,7 @@ static void blk_mq_run_work_fn(struct work_struct *work)
 
 void blk_mq_delay_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs)
 {
-	if (unlikely(!blk_mq_hw_queue_mapped(hctx)))
+	if (WARN_ON_ONCE(!blk_mq_hw_queue_mapped(hctx)))
 		return;
 
 	/*