NFS: Enable client side NFSv4.1 backchannel to use other transports

Forechannel transports get their own "bc_up" method to create an
endpoint for the backchannel service.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
[Anna Schumaker: Add forward declaration of struct net to xprt.h]
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

6 files changed, 46 insertions, 32 deletions

diff --git a/fs/nfs/callback.c b/fs/nfs/callback.c
index 75f7c0a7538a..a7f2e6e33305 100644
--- a/fs/nfs/callback.c
+++ b/fs/nfs/callback.c
@@ -99,17 +99,6 @@ nfs4_callback_up(struct svc_serv *serv)
 }
 
 #if defined(CONFIG_NFS_V4_1)
-static int nfs41_callback_up_net(struct svc_serv *serv, struct net *net)
-{
-        /*
-         * Create an svc_sock for the back channel service that shares the
-         * fore channel connection.
-         * Returns the input port (0) and sets the svc_serv bc_xprt on success
-         */
-        return svc_create_xprt(serv, "tcp-bc", net, PF_INET, 0,
-                              SVC_SOCK_ANONYMOUS);
-}
-
 /*
  * The callback service for NFSv4.1 callbacks
  */
@@ -184,11 +173,6 @@ static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
                 xprt->bc_serv = serv;
 }
 #else
-static int nfs41_callback_up_net(struct svc_serv *serv, struct net *net)
-{
-        return 0;
-}
-
 static void nfs_minorversion_callback_svc_setup(struct svc_serv *serv,
                 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
 {
@@ -259,7 +243,8 @@ static void nfs_callback_down_net(u32 minorversion, struct svc_serv *serv, struc
         svc_shutdown_net(serv, net);
 }
 
-static int nfs_callback_up_net(int minorversion, struct svc_serv *serv, struct net *net)
+static int nfs_callback_up_net(int minorversion, struct svc_serv *serv,
+                               struct net *net, struct rpc_xprt *xprt)
 {
         struct nfs_net *nn = net_generic(net, nfs_net_id);
         int ret;
@@ -275,20 +260,11 @@ static int nfs_callback_up_net(int minorversion, struct svc_serv *serv, struct n
                 goto err_bind;
         }
 
-        switch (minorversion) {
-                case 0:
-                        ret = nfs4_callback_up_net(serv, net);
-                        break;
-                case 1:
-                case 2:
-                        ret = nfs41_callback_up_net(serv, net);
-                        break;
-                default:
-                        printk(KERN_ERR "NFS: unknown callback version: %d\n",
-                                        minorversion);
-                        ret = -EINVAL;
-                        break;
-        }
+        ret = -EPROTONOSUPPORT;
+        if (minorversion == 0)
+                ret = nfs4_callback_up_net(serv, net);
+        else if (xprt->ops->bc_up)
+                ret = xprt->ops->bc_up(serv, net);
 
         if (ret < 0) {
                 printk(KERN_ERR "NFS: callback service start failed\n");
@@ -364,7 +340,7 @@ int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
                 goto err_create;
         }
 
-        ret = nfs_callback_up_net(minorversion, serv, net);
+        ret = nfs_callback_up_net(minorversion, serv, net, xprt);
         if (ret < 0)
                 goto err_net;
 
diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index 82c083946ef0..69ef5b3ab038 100644
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -54,6 +54,8 @@ enum rpc_display_format_t {
 struct rpc_task;
 struct rpc_xprt;
 struct seq_file;
+struct svc_serv;
+struct net;
 
 /*
  * This describes a complete RPC request
@@ -138,6 +140,7 @@ struct rpc_xprt_ops {
         void            (*inject_disconnect)(struct rpc_xprt *xprt);
         int             (*bc_setup)(struct rpc_xprt *xprt,
                                     unsigned int min_reqs);
+        int             (*bc_up)(struct svc_serv *serv, struct net *net);
         void            (*bc_free_rqst)(struct rpc_rqst *rqst);
         void            (*bc_destroy)(struct rpc_xprt *xprt,
                                       unsigned int max_reqs);
diff --git a/net/sunrpc/xprtrdma/backchannel.c b/net/sunrpc/xprtrdma/backchannel.c
index 0b3387fe3f0d..2dcb44f69e53 100644
--- a/net/sunrpc/xprtrdma/backchannel.c
+++ b/net/sunrpc/xprtrdma/backchannel.c
@@ -7,6 +7,7 @@
 #include <linux/module.h>
 #include <linux/sunrpc/xprt.h>
 #include <linux/sunrpc/svc.h>
+#include <linux/sunrpc/svc_xprt.h>
 
 #include "xprt_rdma.h"
 
@@ -174,6 +175,26 @@ out_err:
 }
 
 /**
+ * xprt_rdma_bc_up - Create transport endpoint for backchannel service
+ * @serv: server endpoint
+ * @net: network namespace
+ *
+ * The "xprt" is an implied argument: it supplies the name of the
+ * backchannel transport class.
+ *
+ * Returns zero on success, negative errno on failure
+ */
+int xprt_rdma_bc_up(struct svc_serv *serv, struct net *net)
+{
+        int ret;
+
+        ret = svc_create_xprt(serv, "rdma-bc", net, PF_INET, 0, 0);
+        if (ret < 0)
+                return ret;
+        return 0;
+}
+
+/**
  * rpcrdma_bc_marshal_reply - Send backwards direction reply
  * @rqst: buffer containing RPC reply data
  *
diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c
index 845278e63be0..8c545f7d7525 100644
--- a/net/sunrpc/xprtrdma/transport.c
+++ b/net/sunrpc/xprtrdma/transport.c
@@ -708,6 +708,7 @@ static struct rpc_xprt_ops xprt_rdma_procs = {
         .inject_disconnect      = xprt_rdma_inject_disconnect,
 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
         .bc_setup               = xprt_rdma_bc_setup,
+        .bc_up                  = xprt_rdma_bc_up,
         .bc_free_rqst           = xprt_rdma_bc_free_rqst,
         .bc_destroy             = xprt_rdma_bc_destroy,
 #endif
diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h
index eb87d96e80ca..f8dd17be9f43 100644
--- a/net/sunrpc/xprtrdma/xprt_rdma.h
+++ b/net/sunrpc/xprtrdma/xprt_rdma.h
@@ -520,6 +520,7 @@ void xprt_rdma_cleanup(void);
  */
 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
 int xprt_rdma_bc_setup(struct rpc_xprt *, unsigned int);
+int xprt_rdma_bc_up(struct svc_serv *, struct net *);
 int rpcrdma_bc_post_recv(struct rpcrdma_xprt *, unsigned int);
 void rpcrdma_bc_receive_call(struct rpcrdma_xprt *, struct rpcrdma_rep *);
 int rpcrdma_bc_marshal_reply(struct rpc_rqst *);
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 44a81e4c6783..dc4706711224 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -1306,6 +1306,17 @@ static inline int _xs_tcp_read_data(struct rpc_xprt *xprt,
                 xs_tcp_read_reply(xprt, desc) :
                 xs_tcp_read_callback(xprt, desc);
 }
+
+static int xs_tcp_bc_up(struct svc_serv *serv, struct net *net)
+{
+        int ret;
+
+        ret = svc_create_xprt(serv, "tcp-bc", net, PF_INET, 0,
+                              SVC_SOCK_ANONYMOUS);
+        if (ret < 0)
+                return ret;
+        return 0;
+}
 #else
 static inline int _xs_tcp_read_data(struct rpc_xprt *xprt,
                                         struct xdr_skb_reader *desc)
@@ -2582,6 +2593,7 @@ static struct rpc_xprt_ops xs_tcp_ops = {
         .inject_disconnect      = xs_inject_disconnect,
 #ifdef CONFIG_SUNRPC_BACKCHANNEL
         .bc_setup               = xprt_setup_bc,
+        .bc_up                  = xs_tcp_bc_up,
         .bc_free_rqst           = xprt_free_bc_rqst,
         .bc_destroy             = xprt_destroy_bc,
 #endif