blk-mq: change blk_mq_queue_busy() to blk_mq_queue_inflight()

axboe · axboe · commit 3c94d83cb352 · 2018-12-17T21:31:42.000-07:00
There's a single user of this function, dm, and dm just wants
to check if IO is inflight, not that it's just allocated.

This fixes a hang with srp/002 in blktests with dm, where it tries
to suspend but waits for inflight IO to finish first. As it checks
for just allocated requests, this fails.

Tested-by: Mike Snitzer &lt;snitzer@redhat.com&gt;
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
diff --git a/block/blk-mq.c b/block/blk-mq.c
@@ -805,14 +805,14 @@ struct request *blk_mq_tag_to_rq(struct blk_mq_tags *tags, unsigned int tag)
 }
 EXPORT_SYMBOL(blk_mq_tag_to_rq);
 
-static bool blk_mq_check_busy(struct blk_mq_hw_ctx *hctx, struct request *rq,
-			      void *priv, bool reserved)
+static bool blk_mq_rq_inflight(struct blk_mq_hw_ctx *hctx, struct request *rq,
+			       void *priv, bool reserved)
 {
 	/*
-	 * If we find a request, we know the queue is busy. Return false
-	 * to stop the iteration.
+	 * If we find a request that is inflight and the queue matches,
+	 * we know the queue is busy. Return false to stop the iteration.
 	 */
-	if (rq->q == hctx->queue) {
+	if (rq->state == MQ_RQ_IN_FLIGHT && rq->q == hctx->queue) {
 		bool *busy = priv;
 
 		*busy = true;
@@ -822,14 +822,14 @@ static bool blk_mq_check_busy(struct blk_mq_hw_ctx *hctx, struct request *rq,
 	return true;
 }
 
-bool blk_mq_queue_busy(struct request_queue *q)
+bool blk_mq_queue_inflight(struct request_queue *q)
 {
 	bool busy = false;
 
-	blk_mq_queue_tag_busy_iter(q, blk_mq_check_busy, &busy);
+	blk_mq_queue_tag_busy_iter(q, blk_mq_rq_inflight, &busy);
 	return busy;
 }
-EXPORT_SYMBOL_GPL(blk_mq_queue_busy);
+EXPORT_SYMBOL_GPL(blk_mq_queue_inflight);
 
 static void blk_mq_rq_timed_out(struct request *req, bool reserved)
 {
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
@@ -663,7 +663,7 @@ static bool md_in_flight_bios(struct mapped_device *md)
 static bool md_in_flight(struct mapped_device *md)
 {
 	if (queue_is_mq(md->queue))
-		return blk_mq_queue_busy(md->queue);
+		return blk_mq_queue_inflight(md->queue);
 	else
 		return md_in_flight_bios(md);
 }
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
@@ -257,7 +257,7 @@ void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule);
 void blk_mq_free_request(struct request *rq);
 bool blk_mq_can_queue(struct blk_mq_hw_ctx *);
 
-bool blk_mq_queue_busy(struct request_queue *q);
+bool blk_mq_queue_inflight(struct request_queue *q);
 
 enum {
 	/* return when out of requests */

Original file line number	Diff line number	Diff line change
`@@ -805,14 +805,14 @@ struct request blk_mq_tag_to_rq(struct blk_mq_tags tags, unsigned int tag)`
`805`	`805`	`}`
`806`	`806`	`EXPORT_SYMBOL(blk_mq_tag_to_rq);`
`807`	`807`
`808`		`-static bool blk_mq_check_busy(struct blk_mq_hw_ctx hctx, struct request rq,`
`809`		`- void *priv, bool reserved)`
	`808`	`+static bool blk_mq_rq_inflight(struct blk_mq_hw_ctx hctx, struct request rq,`
	`809`	`+ void *priv, bool reserved)`
`810`	`810`	`{`
`811`	`811`	`/*`
`812`		`- * If we find a request, we know the queue is busy. Return false`
`813`		`- * to stop the iteration.`
	`812`	`+ * If we find a request that is inflight and the queue matches,`
	`813`	`+ * we know the queue is busy. Return false to stop the iteration.`
`814`	`814`	`*/`
`815`		`- if (rq->q == hctx->queue) {`
	`815`	`+ if (rq->state == MQ_RQ_IN_FLIGHT && rq->q == hctx->queue) {`
`816`	`816`	`bool *busy = priv;`
`817`	`817`
`818`	`818`	`*busy = true;`
`@@ -822,14 +822,14 @@ static bool blk_mq_check_busy(struct blk_mq_hw_ctx hctx, struct request rq,`
`822`	`822`	`return true;`
`823`	`823`	`}`
`824`	`824`
`825`		`-bool blk_mq_queue_busy(struct request_queue *q)`
	`825`	`+bool blk_mq_queue_inflight(struct request_queue *q)`
`826`	`826`	`{`
`827`	`827`	`bool busy = false;`
`828`	`828`
`829`		`- blk_mq_queue_tag_busy_iter(q, blk_mq_check_busy, &busy);`
	`829`	`+ blk_mq_queue_tag_busy_iter(q, blk_mq_rq_inflight, &busy);`
`830`	`830`	`return busy;`
`831`	`831`	`}`
`832`		`-EXPORT_SYMBOL_GPL(blk_mq_queue_busy);`
	`832`	`+EXPORT_SYMBOL_GPL(blk_mq_queue_inflight);`
`833`	`833`
`834`	`834`	`static void blk_mq_rq_timed_out(struct request *req, bool reserved)`
`835`	`835`	`{`
Original file line number	Diff line number	Diff line change
`@@ -663,7 +663,7 @@ static bool md_in_flight_bios(struct mapped_device *md)`
`663`	`663`	`static bool md_in_flight(struct mapped_device *md)`
`664`	`664`	`{`
`665`	`665`	`if (queue_is_mq(md->queue))`
`666`		`- return blk_mq_queue_busy(md->queue);`
	`666`	`+ return blk_mq_queue_inflight(md->queue);`
`667`	`667`	`else`
`668`	`668`	`return md_in_flight_bios(md);`
`669`	`669`	`}`