[v2] nbd:fix memory leak in nbd_get_socket()

[Sun Ke <sunke32@xxxxxxxxxx>]

Before return NULL,put the sock first.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: cf1b2326b734 ("nbd: verify socket is supported during setup")
Signed-off-by: Sun Ke <sunke32@xxxxxxxxxx>
---
v2: add cc:stable tag
---
 drivers/block/nbd.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index a94ee45..19e7599 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -993,6 +993,7 @@ static struct socket *nbd_get_socket(struct nbd_device *nbd, unsigned long fd,
 	if (sock->ops->shutdown == sock_no_shutdown) {
 		dev_err(disk_to_dev(nbd->disk), "Unsupported socket: shutdown callout must be supported.\n");
 		*err = -EINVAL;
+		sockfd_put(sock);
 		return NULL;
 	}
 
-- 
2.7.4