SUNRPC: Finish API to load RPC transport implementations dynamically

Allow RPC client transport implementations to be loaded as needed, or
as they become available from distributors or third-party vendors.

Note that we leave the IP sockets implementation in sunrpc.o
permanently, as IP functionality is always available in any
kernel that runs NFS.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Tom Talpey <tmt@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 15 insertions, 11 deletions

diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index 520859622af5..7f8c60b84396 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -983,19 +983,23 @@ struct rpc_xprt *xprt_create_transport(struct rpc_xprtsock_create *args)
 {
         struct rpc_xprt *xprt;
         struct rpc_rqst *req;
+        struct xprt_class *t;
 
-        switch (args->proto) {
-        case IPPROTO_UDP:
-                xprt = xs_setup_udp(args);
-                break;
-        case IPPROTO_TCP:
-                xprt = xs_setup_tcp(args);
-                break;
-        default:
-                printk(KERN_ERR "RPC: unrecognized transport protocol: %d\n",
-                                args->proto);
-                return ERR_PTR(-EIO);
+        spin_lock(&xprt_list_lock);
+        list_for_each_entry(t, &xprt_list, list) {
+                if ((t->family == args->dstaddr->sa_family) &&
+                    (t->protocol == args->proto)) {
+                        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);
+        return ERR_PTR(-EIO);
+
+found:
+        xprt = t->setup(args);
         if (IS_ERR(xprt)) {
                 dprintk("RPC:       xprt_create_transport: failed, %ld\n",
                                 -PTR_ERR(xprt));