LOCKD: Fix a race when initialising nlmsvc_timeout

commit 06bed7d1 upstream.

This commit fixes a race whereby nlmclnt_init() first starts the lockd
daemon, and then calls nlm_bind_host() with the expectation that
nlmsvc_timeout has already been initialised. Unfortunately, there is no
no synchronisation between lockd() and lockd_up() to guarantee that this
is the case.

Fix is to move the initialisation of nlmsvc_timeout into lockd_create_svc

Fixes: 9a1b6bf8 ("LOCKD: Don't call utsname()->nodename...")
Cc: Bruce Fields <bfields@fieldses.org>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

fs/lockd/svc.c

@@ -137,10 +137,6 @@ lockd(void *vrqstp)
 
 	dprintk("NFS locking service started (ver " LOCKD_VERSION ").\n");
 
-	if (!nlm_timeout)
-		nlm_timeout = LOCKD_DFLT_TIMEO;
-	nlmsvc_timeout = nlm_timeout * HZ;
-
 	/*
 	 * The main request loop. We don't terminate until the last
 	 * NFS mount or NFS daemon has gone away.
@@ -346,6 +342,10 @@ static struct svc_serv *lockd_create_svc(void)
 		printk(KERN_WARNING
 			"lockd_up: no pid, %d users??\n", nlmsvc_users);
 
+	if (!nlm_timeout)
+		nlm_timeout = LOCKD_DFLT_TIMEO;
+	nlmsvc_timeout = nlm_timeout * HZ;
+
 	serv = svc_create(&nlmsvc_program, LOCKD_BUFSIZE, NULL);
 	if (!serv) {
 		printk(KERN_WARNING "lockd_up: create service failed\n");