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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, David Jeffery <djeffery@redhat.com>,
        Xiao Ni <xni@redhat.com>, Shaohua Li <shli@fb.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 134/361] MD: Memory leak when flush bio size is zero
Date:   Sun, 11 Nov 2018 14:18:01 -0800
Message-Id: <20181111221639.154959645@linuxfoundation.org>
In-Reply-To: <20181111221619.915519183@linuxfoundation.org>
References: <20181111221619.915519183@linuxfoundation.org>
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4.19-stable review patch.  If anyone has any objections, please let me know.

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

From: Xiao Ni <xni@redhat.com>

[ 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@redhat.com>
Signed-off-by: Xiao Ni <xni@redhat.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/md/md.c |   10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -452,10 +452,11 @@ 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);
 		}
@@ -509,10 +510,11 @@ 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);
 		}