SUNRPC new transport for the NFSv4.1 shared back channel

Move the current sock create and destroy routines into the new transport ops.
Back channel socket will be destroyed by the svc_closs_all call in svc_destroy.

Added check: only TCP supported on shared back channel.
Signed-off-by: Andy Adamson <andros@netapp.com>
Acked-by: Bruce Fields <bfields@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

include/linux/sunrpc/svcsock.h

@@ -45,6 +45,7 @@ int		svc_sock_names(struct svc_serv *serv, char *buf,
 int		svc_addsock(struct svc_serv *serv, const int fd,
 					char *name_return, const size_t len);
 void		svc_init_xprt_sock(void);
+void		svc_init_bc_xprt_sock(void);
 void		svc_cleanup_xprt_sock(void);
 struct svc_xprt *svc_sock_create(struct svc_serv *serv, int prot);
 void		svc_sock_destroy(struct svc_xprt *);

net/sunrpc/svc.c

@@ -488,10 +488,6 @@ svc_destroy(struct svc_serv *serv)
 	if (svc_serv_is_pooled(serv))
 		svc_pool_map_put();
 
-#if defined(CONFIG_NFS_V4_1)
-	svc_sock_destroy(serv->bc_xprt);
-#endif /* CONFIG_NFS_V4_1 */
-
 	svc_unregister(serv);
 	kfree(serv->sv_pools);
 	kfree(serv);

net/sunrpc/svcsock.c

@@ -66,6 +66,13 @@ static void		svc_sock_free(struct svc_xprt *);
 static struct svc_xprt *svc_create_socket(struct svc_serv *, int,
 					  struct net *, struct sockaddr *,
 					  int, int);
+#if defined(CONFIG_NFS_V4_1)
+static struct svc_xprt *svc_bc_create_socket(struct svc_serv *, int,
+					     struct net *, struct sockaddr *,
+					     int, int);
+static void svc_bc_sock_free(struct svc_xprt *xprt);
+#endif /* CONFIG_NFS_V4_1 */
+
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 static struct lock_class_key svc_key[2];
 static struct lock_class_key svc_slock_key[2];
@@ -1184,6 +1191,39 @@ static struct svc_xprt *svc_tcp_create(struct svc_serv *serv,
 	return svc_create_socket(serv, IPPROTO_TCP, net, sa, salen, flags);
 }
 
+#if defined(CONFIG_NFS_V4_1)
+static struct svc_xprt *svc_bc_create_socket(struct svc_serv *, int,
+					     struct net *, struct sockaddr *,
+					     int, int);
+static void svc_bc_sock_free(struct svc_xprt *xprt);
+
+static struct svc_xprt *svc_bc_tcp_create(struct svc_serv *serv,
+				       struct net *net,
+				       struct sockaddr *sa, int salen,
+				       int flags)
+{
+	return svc_bc_create_socket(serv, IPPROTO_TCP, net, sa, salen, flags);
+}
+
+static void svc_bc_tcp_sock_detach(struct svc_xprt *xprt)
+{
+}
+
+static struct svc_xprt_ops svc_tcp_bc_ops = {
+	.xpo_create = svc_bc_tcp_create,
+	.xpo_detach = svc_bc_tcp_sock_detach,
+	.xpo_free = svc_bc_sock_free,
+	.xpo_prep_reply_hdr = svc_tcp_prep_reply_hdr,
+};
+
+static struct svc_xprt_class svc_tcp_bc_class = {
+	.xcl_name = "tcp-bc",
+	.xcl_owner = THIS_MODULE,
+	.xcl_ops = &svc_tcp_bc_ops,
+	.xcl_max_payload = RPCSVC_MAXPAYLOAD_TCP,
+};
+#endif /* CONFIG_NFS_V4_1 */
+
 static struct svc_xprt_ops svc_tcp_ops = {
 	.xpo_create = svc_tcp_create,
 	.xpo_recvfrom = svc_tcp_recvfrom,
@@ -1509,41 +1549,43 @@ static void svc_sock_free(struct svc_xprt *xprt)
 	kfree(svsk);
 }
 
+#if defined(CONFIG_NFS_V4_1)
 /*
- * Create a svc_xprt.
- *
- * For internal use only (e.g. nfsv4.1 backchannel).
- * Callers should typically use the xpo_create() method.
+ * Create a back channel svc_xprt which shares the fore channel socket.
  */
-struct svc_xprt *svc_sock_create(struct svc_serv *serv, int prot)
+static struct svc_xprt *svc_bc_create_socket(struct svc_serv *serv,
+					     int protocol,
+					     struct net *net,
+					     struct sockaddr *sin, int len,
+					     int flags)
 {
 	struct svc_sock *svsk;
-	struct svc_xprt *xprt = NULL;
+	struct svc_xprt *xprt;
+
+	if (protocol != IPPROTO_TCP) {
+		printk(KERN_WARNING "svc: only TCP sockets"
+			" supported on shared back channel\n");
+		return ERR_PTR(-EINVAL);
+	}
 
-	dprintk("svc: %s\n", __func__);
 	svsk = kzalloc(sizeof(*svsk), GFP_KERNEL);
 	if (!svsk)
-		goto out;
+		return ERR_PTR(-ENOMEM);
 
 	xprt = &svsk->sk_xprt;
-	if (prot == IPPROTO_TCP)
-		svc_xprt_init(&svc_tcp_class, xprt, serv);
-	else if (prot == IPPROTO_UDP)
-		svc_xprt_init(&svc_udp_class, xprt, serv);
-	else
-		BUG();
-out:
-	dprintk("svc: %s return %p\n", __func__, xprt);
+	svc_xprt_init(&svc_tcp_bc_class, xprt, serv);
+
+	serv->bc_xprt = xprt;
+
 	return xprt;
 }
-EXPORT_SYMBOL_GPL(svc_sock_create);
 
 /*
- * Destroy a svc_sock.
+ * Free a back channel svc_sock.
  */
-void svc_sock_destroy(struct svc_xprt *xprt)
+static void svc_bc_sock_free(struct svc_xprt *xprt)
 {
 	if (xprt)
 		kfree(container_of(xprt, struct svc_sock, sk_xprt));
 }
-EXPORT_SYMBOL_GPL(svc_sock_destroy);
+#endif /* CONFIG_NFS_V4_1 */