net/9p: Fix a potential socket leak in p9_socket_open

Both p9_fd_create_tcp() and p9_fd_create_unix() will call
p9_socket_open(). If the creation of p9_trans_fd fails,
p9_fd_create_tcp() and p9_fd_create_unix() will return an
error directly instead of releasing the cscoket, which will
result in a socket leak.

This patch adds sock_release() to fix the leak issue.

Fixes: 6b18662e239a ("9p connect fixes")
Signed-off-by: Wang Hai <[e-mail]>
ACKed-by: Al Viro <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/9p/trans_fd.c

···
 	struct file *file;
 
 	p = kzalloc(sizeof(struct p9_trans_fd), GFP_KERNEL);
-	if (!p)
+	if (!p) {
+		sock_release(csocket);
 		return -ENOMEM;
+	}
 
 	csocket->sk->sk_allocation = GFP_NOIO;
 	file = sock_alloc_file(csocket, 0, NULL);