[PATCH] md/raid1: free r1_bio when REQ_NOWAIT is set and read would block on retry

When a read is retried, raid1_read_request() may be called with a
pre-allocated r1_bio. If wait_read_barrier() fails for a REQ_NOWAIT
read, the bio is completed and the function returns immediately. In this
case the existing r1_bio is leaked.

This fixes a leak of pre-allocated r1_bio structures for retried reads.

Fixes: 5aa705039c4f ("md: raid1 add nowait support")
Reported-by: sashiko-bot <[email protected]>
Closes: https://sashiko.dev/#/patchset/[email protected]?part=1
Signed-off-by: Abd-Alrhman Masalkhi <[email protected]>
---
 drivers/md/raid1.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index b2d7c13b64bd..6263a1d45f86 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1363,6 +1363,12 @@ static void raid1_read_request(struct mddev *mddev, struct bio *bio,
 	 */
 	if (!wait_read_barrier(conf, bio->bi_iter.bi_sector, nowait)) {
 		bio_wouldblock_error(bio);
+
+		if (r1bio_existed) {
+			set_bit(R1BIO_Returned, &r1_bio->state);
+			raid_end_bio_io(r1_bio);
+		}
+
 		return;
 	}
 
-- 
2.43.0