[PATCH 4.18 138/350] MD: Memory leak when flush bio size is zero

[Greg Kroah-Hartman]

4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Xiao Ni <xni@xxxxxxxxxx>

[ Upstream commit af9b926de9c5986ab009e64917de87c9758bab10 ]

flush_pool is leaked when flush bio size is zero

Fixes: 5a409b4f56d5 ("MD: fix lock contention for flush bios")
Signed-off-by: David Jeffery <djeffery@xxxxxxxxxx>
Signed-off-by: Xiao Ni <xni@xxxxxxxxxx>
Signed-off-by: Shaohua Li <shli@xxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/md/md.c |   10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -455,10 +455,11 @@ static void md_end_flush(struct bio *fbi
 	rdev_dec_pending(rdev, mddev);
 
 	if (atomic_dec_and_test(&fi->flush_pending)) {
-		if (bio->bi_iter.bi_size == 0)
+		if (bio->bi_iter.bi_size == 0) {
 			/* an empty barrier - all done */
 			bio_endio(bio);
-		else {
+			mempool_free(fi, mddev->flush_pool);
+		} else {
 			INIT_WORK(&fi->flush_work, submit_flushes);
 			queue_work(md_wq, &fi->flush_work);
 		}
@@ -512,10 +513,11 @@ void md_flush_request(struct mddev *mdde
 	rcu_read_unlock();
 
 	if (atomic_dec_and_test(&fi->flush_pending)) {
-		if (bio->bi_iter.bi_size == 0)
+		if (bio->bi_iter.bi_size == 0) {
 			/* an empty barrier - all done */
 			bio_endio(bio);
-		else {
+			mempool_free(fi, mddev->flush_pool);
+		} else {
 			INIT_WORK(&fi->flush_work, submit_flushes);
 			queue_work(md_wq, &fi->flush_work);
 		}