svc: Add a max payload value to the transport

The svc_max_payload function currently looks at the socket type
to determine the max payload. Add a max payload value to svc_xprt_class
so it can be returned directly.

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>

include/linux/sunrpc/svc_xprt.h

@@ -17,6 +17,7 @@ struct svc_xprt_class {
 	struct module		*xcl_owner;
 	struct svc_xprt_ops	*xcl_ops;
 	struct list_head	xcl_list;
+	u32			xcl_max_payload;
 };
 
 struct svc_xprt {

net/sunrpc/svc.c

@@ -1055,10 +1055,8 @@ err_bad:
  */
 u32 svc_max_payload(const struct svc_rqst *rqstp)
 {
-	int max = RPCSVC_MAXPAYLOAD_TCP;
+	u32 max = rqstp->rq_xprt->xpt_class->xcl_max_payload;
 
-	if (rqstp->rq_sock->sk_sock->type == SOCK_DGRAM)
-		max = RPCSVC_MAXPAYLOAD_UDP;
 	if (rqstp->rq_server->sv_max_payload < max)
 		max = rqstp->rq_server->sv_max_payload;
 	return max;

net/sunrpc/svcsock.c

@@ -906,6 +906,7 @@ static struct svc_xprt_ops svc_udp_ops = {
 static struct svc_xprt_class svc_udp_class = {
 	.xcl_name = "udp",
 	.xcl_ops = &svc_udp_ops,
+	.xcl_max_payload = RPCSVC_MAXPAYLOAD_UDP,
 };
 
 static void
@@ -1359,6 +1360,7 @@ static struct svc_xprt_ops svc_tcp_ops = {
 static struct svc_xprt_class svc_tcp_class = {
 	.xcl_name = "tcp",
 	.xcl_ops = &svc_tcp_ops,
+	.xcl_max_payload = RPCSVC_MAXPAYLOAD_TCP,
 };
 
 void svc_init_xprt_sock(void)