1 files changed, 29 insertions, 1 deletions

diff --git a/block/blk-flush.c b/block/blk-flush.c
index aedd9320e605..3f977c517960 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -69,6 +69,7 @@
 #include <linux/blkdev.h>
 #include <linux/gfp.h>
 #include <linux/blk-mq.h>
+#include <linux/lockdep.h>
 
 #include "blk.h"
 #include "blk-mq.h"
@@ -136,6 +137,17 @@ static void blk_flush_queue_rq(struct request *rq, bool add_front)
 	blk_mq_add_to_requeue_list(rq, add_front, true);
 }
 
+static void blk_account_io_flush(struct request *rq)
+{
+	struct hd_struct *part = &rq->rq_disk->part0;
+
+	part_stat_lock();
+	part_stat_inc(part, ios[STAT_FLUSH]);
+	part_stat_add(part, nsecs[STAT_FLUSH],
+		      ktime_get_ns() - rq->start_time_ns);
+	part_stat_unlock();
+}
+
 /**
  * blk_flush_complete_seq - complete flush sequence
  * @rq: PREFLUSH/FUA request being sequenced
@@ -185,7 +197,7 @@ static void blk_flush_complete_seq(struct request *rq,
 
 	case REQ_FSEQ_DONE:
 		/*
-		 * @rq was previously adjusted by blk_flush_issue() for
+		 * @rq was previously adjusted by blk_insert_flush() for
 		 * flush sequencing and may already have gone through the
 		 * flush data request completion path.  Restore @rq for
 		 * normal completion and end it.
@@ -212,8 +224,20 @@ static void flush_end_io(struct request *flush_rq, blk_status_t error)
 	struct blk_flush_queue *fq = blk_get_flush_queue(q, flush_rq->mq_ctx);
 	struct blk_mq_hw_ctx *hctx;
 
+	blk_account_io_flush(flush_rq);
+
 	/* release the tag's ownership to the req cloned from */
 	spin_lock_irqsave(&fq->mq_flush_lock, flags);
+
+	if (!refcount_dec_and_test(&flush_rq->ref)) {
+		fq->rq_status = error;
+		spin_unlock_irqrestore(&fq->mq_flush_lock, flags);
+		return;
+	}
+
+	if (fq->rq_status != BLK_STS_OK)
+		error = fq->rq_status;
+
 	hctx = flush_rq->mq_hctx;
 	if (!q->elevator) {
 		blk_mq_tag_set_rq(hctx, flush_rq->tag, fq->orig_rq);
@@ -482,6 +506,9 @@ struct blk_flush_queue *blk_alloc_flush_queue(struct request_queue *q,
 	INIT_LIST_HEAD(&fq->flush_queue[1]);
 	INIT_LIST_HEAD(&fq->flush_data_in_flight);
 
+	lockdep_register_key(&fq->key);
+	lockdep_set_class(&fq->mq_flush_lock, &fq->key);
+
 	return fq;
 
  fail_rq:
@@ -496,6 +523,7 @@ void blk_free_flush_queue(struct blk_flush_queue *fq)
 	if (!fq)
 		return;
 
+	lockdep_unregister_key(&fq->key);
 	kfree(fq->flush_rq);
 	kfree(fq);
 }