NFS: callback up - transport backchannel cleanup

No need to assign transports backchannel server explicitly in
nfs41_callback_up() -  there is nfs_callback_bc_serv() function for this.
By using it, nfs4_callback_up() and nfs41_callback_up() can be called without
transport argument.

Note: service have to be passed to nfs_callback_bc_serv() instead of callback,
since callback link can be uninitialized.
Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/callback.c

@@ -104,7 +104,7 @@ nfs4_callback_svc(void *vrqstp)
  * Prepare to bring up the NFSv4 callback service
  */
 static struct svc_rqst *
-nfs4_callback_up(struct svc_serv *serv, struct rpc_xprt *xprt)
+nfs4_callback_up(struct svc_serv *serv)
 {
 	return svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE);
 }
@@ -160,16 +160,10 @@ nfs41_callback_svc(void *vrqstp)
  * Bring up the NFSv4.1 callback service
  */
 static struct svc_rqst *
-nfs41_callback_up(struct svc_serv *serv, struct rpc_xprt *xprt)
+nfs41_callback_up(struct svc_serv *serv)
 {
 	struct svc_rqst *rqstp;
 
-	/*
-	 * Save the svc_serv in the transport so that it can
-	 * be referenced when the session backchannel is initialized
-	 */
-	xprt->bc_serv = serv;
-
 	INIT_LIST_HEAD(&serv->sv_cb_list);
 	spin_lock_init(&serv->sv_cb_lock);
 	init_waitqueue_head(&serv->sv_cb_waitq);
@@ -184,21 +178,25 @@ nfs41_callback_up(struct svc_serv *serv, struct rpc_xprt *xprt)
 }
 
 static inline int nfs_minorversion_callback_svc_setup(u32 minorversion,
-		struct svc_serv *serv, struct rpc_xprt *xprt,
+		struct svc_serv *serv,
 		struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
 {
 	if (minorversion) {
-		*rqstpp = nfs41_callback_up(serv, xprt);
+		*rqstpp = nfs41_callback_up(serv);
 		*callback_svc = nfs41_callback_svc;
 	}
 	return minorversion;
 }
 
 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
-		struct nfs_callback_data *cb_info)
+		struct svc_serv *serv)
 {
 	if (minorversion)
-		xprt->bc_serv = cb_info->serv;
+		/*
+		 * Save the svc_serv in the transport so that it can
+		 * be referenced when the session backchannel is initialized
+		 */
+		xprt->bc_serv = serv;
 }
 #else
 static int nfs41_callback_up_net(struct svc_serv *serv, struct net *net)
@@ -207,14 +205,14 @@ static int nfs41_callback_up_net(struct svc_serv *serv, struct net *net)
 }
 
 static inline int nfs_minorversion_callback_svc_setup(u32 minorversion,
-		struct svc_serv *serv, struct rpc_xprt *xprt,
+		struct svc_serv *serv,
 		struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
 {
 	return 0;
 }
 
 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
-		struct nfs_callback_data *cb_info)
+		struct svc_serv *serv)
 {
 }
 #endif /* CONFIG_NFS_V4_1 */
@@ -318,7 +316,7 @@ int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
 	}
 
 	if (cb_info->users++ || cb_info->task != NULL) {
-		nfs_callback_bc_serv(minorversion, xprt, cb_info);
+		nfs_callback_bc_serv(minorversion, xprt, serv);
 		goto out;
 	}
 
@@ -326,11 +324,13 @@ int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
 	if (ret < 0)
 		goto err_net;
 
+	nfs_callback_bc_serv(minorversion, xprt, serv);
+
 	minorversion_setup =  nfs_minorversion_callback_svc_setup(minorversion,
-					serv, xprt, &rqstp, &callback_svc);
+					serv, &rqstp, &callback_svc);
 	if (!minorversion_setup) {
 		/* v4.0 callback setup */
-		rqstp = nfs4_callback_up(serv, xprt);
+		rqstp = nfs4_callback_up(serv);
 		callback_svc = nfs4_callback_svc;
 	}