[PATCH] block: blk-zoned: fix zwplug refcount leak on write error path

[Wentao Liang]

blk_zone_wplug_handle_write() increments zwplug->ref via kref_get()
when preparing to handle a zone write. On the error path where
blk_zone_wplug_handle_write_noalloc() fails, the function returns
without calling kref_put() on zwplug->ref, leaking the reference.

Add kref_put(&zwplug->ref, ...) on the error path to properly release
the reference.

Fixes: dd291d77cc90 ("block: Introduce zone write plugging")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Wentao Liang <vulab@xxxxxxxxxxx>
---
 block/blk-zoned.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index 42ef830054dc..24b899663a48 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -1503,6 +1503,7 @@ static bool blk_zone_wplug_handle_write(struct bio *bio, unsigned int nr_segs)
 
 	if (!blk_zone_wplug_prepare_bio(zwplug, bio)) {
 		spin_unlock_irqrestore(&zwplug->lock, flags);
+		disk_put_zone_wplug(zwplug);
 		bio_io_error(bio);
 		return true;
 	}
@@ -1511,6 +1512,7 @@ static bool blk_zone_wplug_handle_write(struct bio *bio, unsigned int nr_segs)
 	zwplug->flags |= BLK_ZONE_WPLUG_PLUGGED;
 
 	spin_unlock_irqrestore(&zwplug->lock, flags);
+	disk_put_zone_wplug(zwplug);
 
 	return false;
 
-- 
2.34.1