NFS: Fix NFS4 callback up/down prototypes

Make the nfs_callback_up()/down() prototypes just do nothing if NFS4 is not
enabled.  Also make the down function void type since we can't really do
anything if it fails.
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/callback.c

@@ -149,10 +149,8 @@ int nfs_callback_up(void)
 /*
  * Kill the server process if it is not already up.
  */
-int nfs_callback_down(void)
+void nfs_callback_down(void)
 {
-	int ret = 0;
-
 	lock_kernel();
 	mutex_lock(&nfs_callback_mutex);
 	nfs_callback_info.users--;
@@ -164,7 +162,6 @@ int nfs_callback_down(void)
 	} while (wait_for_completion_timeout(&nfs_callback_info.stopped, 5*HZ) == 0);
 	mutex_unlock(&nfs_callback_mutex);
 	unlock_kernel();
-	return ret;
 }
 
 static int nfs_callback_authenticate(struct svc_rqst *rqstp)

fs/nfs/callback.h

@@ -62,8 +62,13 @@ struct cb_recallargs {
 extern unsigned nfs4_callback_getattr(struct cb_getattrargs *args, struct cb_getattrres *res);
 extern unsigned nfs4_callback_recall(struct cb_recallargs *args, void *dummy);
 
+#ifdef CONFIG_NFS_V4
 extern int nfs_callback_up(void);
-extern int nfs_callback_down(void);
+extern void nfs_callback_down(void);
+#else
+#define nfs_callback_up()	(0)
+#define nfs_callback_down()	do {} while(0)
+#endif
 
 extern unsigned int nfs_callback_set_tcpport;
 extern unsigned short nfs_callback_tcpport;