3 files changed, 63 insertions, 24 deletions

diff --git a/include/linux/sunrpc/svcsock.h b/include/linux/sunrpc/svcsock.h
index 1b353a76c304..3a45a80760b9 100644
--- a/include/linux/sunrpc/svcsock.h
+++ b/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 *);
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index 606d182895a9..261e2d1dff10 100644
--- a/net/sunrpc/svc.c
+++ b/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);
diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index 07919e16be3e..6630f2922f40 100644
--- a/net/sunrpc/svcsock.c
+++ b/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 */