svc: Add svc_xprt_names service to replace svc_sock_names

Create a transport independent version of the svc_sock_names function.

The toclose capability of the svc_sock_names service can be implemented
using the svc_xprt_find and svc_xprt_close services.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
Acked-by: Neil Brown <neilb@suse.de>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Greg Banks <gnb@sgi.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index eff6a6b..bc22e0b 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -503,7 +503,7 @@
 		int len = 0;
 		lock_kernel();
 		if (nfsd_serv)
-			len = svc_sock_names(buf, nfsd_serv, NULL);
+			len = svc_xprt_names(nfsd_serv, buf, 0);
 		unlock_kernel();
 		return len;
 	}