[PATCH AUTOSEL 5.3 103/203] nbd: add missing config put

Sasha Levin
2019-09-22T19:34:39Z

From: Mike Christie <mchristi@redhat.com>

[ Upstream commit 887e975c4172d0d5670c39ead2f18ba1e4ec8133 ]

Fix bug added with the patch:

commit 8f3ea35929a0806ad1397db99a89ffee0140822a
Author: Josef Bacik <josef@toxicpanda.com>
Date: Mon Jul 16 12:11:35 2018 -0400

nbd: handle unexpected replies better

where if the timeout handler runs when the completion path is and we fail
to grab the mutex in the timeout handler we will leave a config reference
and cannot free the config later.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/block/nbd.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index e21d2ded732b7..a69a90ad92088 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -357,8 +357,10 @@ static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req,
}
config = nbd->config;

- if (!mutex_trylock(&cmd->lock))
+ if (!mutex_trylock(&cmd->lock)) {
+ nbd_config_put(nbd);
return BLK_EH_RESET_TIMER;
+ }

if (config->num_connections > 1) {
dev_err_ratelimited(nbd_to_dev(nbd),
--
2.20.1