[PATCH v2 16/16] NFS: Enable client side NFSv4.1 backchannel to use other transports

[Chuck Lever <chuck.lever@oracle.com>]

Pass the correct backchannel transport class to svc_create_xprt()
when setting up an NFSv4.1 backchannel transport.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 fs/nfs/callback.c               |   33 +++++++++++++++++++++------------
 include/linux/sunrpc/xprt.h     |    1 +
 net/sunrpc/xprtrdma/transport.c |    1 +
 net/sunrpc/xprtsock.c           |    1 +
 4 files changed, 24 insertions(+), 12 deletions(-)

diff --git a/fs/nfs/callback.c b/fs/nfs/callback.c
index 75f7c0a..46ed2c5 100644
--- a/fs/nfs/callback.c
+++ b/fs/nfs/callback.c
@@ -99,15 +99,22 @@ 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
+ */
+static int nfs41_callback_up_net(struct svc_serv *serv, struct net *net,
+				 struct rpc_xprt *xprt)
 {
-	/*
-	 * 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);
+	int ret = -EPROTONOSUPPORT;
+
+	if (xprt->bc_name)
+		ret = svc_create_xprt(serv, xprt->bc_name, net, PF_INET, 0,
+				      SVC_SOCK_ANONYMOUS);
+	dprintk("NFS: svc_create_xprt(%s) returned %d\n",
+		xprt->bc_name, ret);
+	return ret;
 }
 
 /*
@@ -184,7 +191,8 @@ 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)
+static int nfs41_callback_up_net(struct svc_serv *serv, struct net *net,
+				 struct rpc_xprt *xprt)
 {
 	return 0;
 }
@@ -259,7 +267,8 @@ 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;
@@ -281,7 +290,7 @@ static int nfs_callback_up_net(int minorversion, struct svc_serv *serv, struct n
 			break;
 		case 1:
 		case 2:
-			ret = nfs41_callback_up_net(serv, net);
+			ret = nfs41_callback_up_net(serv, net, xprt);
 			break;
 		default:
 			printk(KERN_ERR "NFS: unknown callback version: %d\n",
@@ -364,7 +373,7 @@ 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 82c0839..88bae18 100644
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -170,6 +170,7 @@ struct rpc_xprt {
 	struct sockaddr_storage	addr;		/* server address */
 	size_t			addrlen;	/* size of server address */
 	int			prot;		/* IP protocol */
+	char			*bc_name;	/* backchannel transport */
 
 	unsigned long		cong;		/* current congestion */
 	unsigned long		cwnd;		/* congestion window */
diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c
index 845278e..c60bbc8 100644
--- a/net/sunrpc/xprtrdma/transport.c
+++ b/net/sunrpc/xprtrdma/transport.c
@@ -337,6 +337,7 @@ xprt_setup_rdma(struct xprt_create *args)
 	/* Ensure xprt->addr holds valid server TCP (not RDMA)
 	 * address, for any side protocols which peek at it */
 	xprt->prot = IPPROTO_TCP;
+	xprt->bc_name = "rdma-bc";
 	xprt->addrlen = args->addrlen;
 	memcpy(&xprt->addr, sap, xprt->addrlen);
 
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 3084163..d82d00b 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -2858,6 +2858,7 @@ static struct rpc_xprt *xs_setup_tcp(struct xprt_create *args)
 	transport = container_of(xprt, struct sock_xprt, xprt);
 
 	xprt->prot = IPPROTO_TCP;
+	xprt->bc_name = "tcp-bc";
 	xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;