blk-mq: blk-mq: check quiesce state before queue_rqs

PATCH Applied Keith Busch 2 participants 2 messages Dec 20, 2021 Block layer

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Keith Busch

author

2021-12-20 20:59 UTC #0 lore raw

PATCH v2 1/1 blk-mq: blk-mq: check quiesce state before queue_rqs

The low level drivers don't expect to see new requests after a successful quiesce completes. Check the queue quiesce state within the rcu protected area prior to calling the driver's queue_rqs().

Signed-off-by Keith Busch <[email protected]>

---
v1->v2:

Set new function scope to static

 block/blk-mq.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

block/blk-mq.c +9 -1

index 51991232824a..998a85b5b46c 100644
@@ -2549,6 +2549,14 @@ static void blk_mq_plug_issue_direct(struct blk_plug *plug, bool from_schedule)
 		blk_mq_commit_rqs(hctx, &queued, from_schedule);
 }
 
+static void __blk_mq_flush_plug_list(struct request_queue *q,
+				     struct blk_plug *plug)
+{
+	if (blk_queue_quiesced(q))
+		return;
+	q->mq_ops->queue_rqs(&plug->mq_list);
+}
+
 void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule)
 {
 	struct blk_mq_hw_ctx *this_hctx;

@@ -2580,7 +2588,7 @@ void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule)
 		if (q->mq_ops->queue_rqs &&
 		    !(rq->mq_hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED)) {
 			blk_mq_run_dispatch_ops(q,
-				q->mq_ops->queue_rqs(&plug->mq_list));
+				__blk_mq_flush_plug_list(q, plug));
 			if (rq_list_empty(plug->mq_list))
 				return;
 		}

Signature · 1 line

2.25.4

Jens Axboe

maintainer Applied

2021-12-20 21:04 UTC #1 lore raw

Quoted 3 lines · Keith Busch

The low level drivers don't expect to see new requests after a successful quiesce completes. Check the queue quiesce state within the rcu protected area prior to calling the driver's queue_rqs().

Thanks, applied - I added a Fixes tag as well.

Signature · 1 line

Jens Axboe