block: fix double account of flush request's driver tag

In case of none scheduler, we share data request's driver tag for
flush request, so have to mark the flush request as INFLIGHT for
avoiding double account of this driver tag.

Fixes: 8da9dbd5fad3 ("blk-mq: centralise related handling into blk_mq_get_driver_tag")
Reported-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Tested-by: Matthew Wilcox <willy@infradead.org>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-flush.c b/block/blk-flush.c
index 6e1543c10493399fe23a2d60194e90e0d2ec828c..53abb5c73d99f90a90033855b60f2d27e3546104 100644 (file)
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -308,9 +308,16 @@ static void blk_kick_flush(struct request_queue *q, struct blk_flush_queue *fq,
        flush_rq->mq_ctx = first_rq->mq_ctx;
        flush_rq->mq_hctx = first_rq->mq_hctx;
 
-       if (!q->elevator)
+       if (!q->elevator) {
                flush_rq->tag = first_rq->tag;
-       else
+
+               /*
+                * We borrow data request's driver tag, so have to mark
+                * this flush request as INFLIGHT for avoiding double
+                * account of this driver tag
+                */
+               flush_rq->rq_flags |= RQF_MQ_INFLIGHT;
+       } else
                flush_rq->internal_tag = first_rq->internal_tag;
 
        flush_rq->cmd_flags = REQ_OP_FLUSH | REQ_PREFLUSH;