NFS/SUNRPC: support transport protocol naming

To prepare for including non-sockets-based RPC transports, select
RPC transports by an identifier (to be used in following patches).
Signed-off-by: Tom Talpey <tmt@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

include/linux/sunrpc/xprt.h

@@ -187,7 +187,7 @@ struct rpc_xprt {
 };
 
 struct xprt_create {
-	int			proto;		/* IPPROTO_UDP or IPPROTO_TCP */
+	int			ident;		/* XPRT_TRANSPORT identifier */
 	struct sockaddr *	srcaddr;	/* optional local address */
 	struct sockaddr *	dstaddr;	/* remote peer address */
 	size_t			addrlen;
@@ -196,8 +196,7 @@ struct xprt_create {
 
 struct xprt_class {
 	struct list_head	list;
-	unsigned short		family;
-	int			protocol;
+	int			ident;		/* XPRT_TRANSPORT identifier */
 	struct rpc_xprt *	(*setup)(struct xprt_create *);
 	struct module		*owner;
 	char			name[32];

include/linux/sunrpc/xprtsock.h

@@ -18,6 +18,17 @@ struct rpc_xprt *xs_setup_tcp(struct xprt_create *args);
 int		init_socket_xprt(void);
 void		cleanup_socket_xprt(void);
 
+/*
+ * RPC transport identifiers for UDP, TCP
+ *
+ * To preserve compatibility with the historical use of raw IP protocol
+ * id's for transport selection, these are specified with the previous
+ * values. No such restriction exists for new transports, except that
+ * they may not collide with these values (17 and 6, respectively).
+ */
+#define XPRT_TRANSPORT_UDP	IPPROTO_UDP
+#define XPRT_TRANSPORT_TCP	IPPROTO_TCP
+
 /*
  * RPC slot table sizes for UDP, TCP transports
  */

net/sunrpc/clnt.c

@@ -241,7 +241,7 @@ struct rpc_clnt *rpc_create(struct rpc_create_args *args)
 	struct rpc_xprt *xprt;
 	struct rpc_clnt *clnt;
 	struct xprt_create xprtargs = {
-		.proto = args->protocol,
+		.ident = args->protocol,
 		.srcaddr = args->saddress,
 		.dstaddr = args->address,
 		.addrlen = args->addrsize,

net/sunrpc/xprt.c

@@ -104,7 +104,7 @@ int xprt_register_transport(struct xprt_class *transport)
 	spin_lock(&xprt_list_lock);
 	list_for_each_entry(t, &xprt_list, list) {
 		/* don't register the same transport class twice */
-		if (t == transport)
+		if (t->ident == transport->ident)
 			goto out;
 	}
 
@@ -987,15 +987,13 @@ struct rpc_xprt *xprt_create_transport(struct xprt_create *args)
 
 	spin_lock(&xprt_list_lock);
 	list_for_each_entry(t, &xprt_list, list) {
-		if ((t->family == args->dstaddr->sa_family) &&
-		    (t->protocol == args->proto)) {
+		if (t->ident == args->ident) {
 			spin_unlock(&xprt_list_lock);
 			goto found;
 		}
 	}
 	spin_unlock(&xprt_list_lock);
-	printk(KERN_ERR "RPC: transport (%u/%d) not supported\n",
-			args->dstaddr->sa_family, args->proto);
+	printk(KERN_ERR "RPC: transport (%d) not supported\n", args->ident);
 	return ERR_PTR(-EIO);
 
 found:

net/sunrpc/xprtsock.c

@@ -1955,8 +1955,7 @@ static struct xprt_class	xs_udp_transport = {
 	.list		= LIST_HEAD_INIT(xs_udp_transport.list),
 	.name		= "udp",
 	.owner		= THIS_MODULE,
-	.family		= AF_INET,
-	.protocol	= IPPROTO_UDP,
+	.ident		= IPPROTO_UDP,
 	.setup		= xs_setup_udp,
 };
 
@@ -1964,8 +1963,7 @@ static struct xprt_class	xs_tcp_transport = {
 	.list		= LIST_HEAD_INIT(xs_tcp_transport.list),
 	.name		= "tcp",
 	.owner		= THIS_MODULE,
-	.family		= AF_INET,
-	.protocol	= IPPROTO_TCP,
+	.ident		= IPPROTO_TCP,
 	.setup		= xs_setup_tcp,
 };