svc: Add transport specific xpo_release function

The svc_sock_release function releases pages allocated to a thread. For
UDP this frees the receive skb. For RDMA it will post a receive WR
and bump the client credit count.

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/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index 7817c7e..d46abc8 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -185,14 +185,13 @@
 /*
  * Release an skbuff after use
  */
-static inline void
-svc_release_skb(struct svc_rqst *rqstp)
+static void svc_release_skb(struct svc_rqst *rqstp)
 {
-	struct sk_buff *skb = rqstp->rq_skbuff;
+	struct sk_buff *skb = rqstp->rq_xprt_ctxt;
 	struct svc_deferred_req *dr = rqstp->rq_deferred;
 
 	if (skb) {
-		rqstp->rq_skbuff = NULL;
+		rqstp->rq_xprt_ctxt = NULL;
 
 		dprintk("svc: service %p, releasing skb %p\n", rqstp, skb);
 		skb_free_datagram(rqstp->rq_sock->sk_sk, skb);
@@ -395,7 +394,7 @@
 {
 	struct svc_sock	*svsk = rqstp->rq_sock;
 
-	svc_release_skb(rqstp);
+	rqstp->rq_xprt->xpt_ops->xpo_release_rqst(rqstp);
 
 	svc_free_res_pages(rqstp);
 	rqstp->rq_res.page_len = 0;
@@ -867,7 +866,7 @@
 			skb_free_datagram(svsk->sk_sk, skb);
 			return 0;
 		}
-		rqstp->rq_skbuff = skb;
+		rqstp->rq_xprt_ctxt = skb;
 	}
 
 	rqstp->rq_arg.page_base = 0;
@@ -903,6 +902,7 @@
 static struct svc_xprt_ops svc_udp_ops = {
 	.xpo_recvfrom = svc_udp_recvfrom,
 	.xpo_sendto = svc_udp_sendto,
+	.xpo_release_rqst = svc_release_skb,
 };
 
 static struct svc_xprt_class svc_udp_class = {
@@ -1291,7 +1291,7 @@
 		rqstp->rq_arg.page_len = len - rqstp->rq_arg.head[0].iov_len;
 	}
 
-	rqstp->rq_skbuff      = NULL;
+	rqstp->rq_xprt_ctxt   = NULL;
 	rqstp->rq_prot	      = IPPROTO_TCP;
 
 	/* Reset TCP read info */
@@ -1357,6 +1357,7 @@
 static struct svc_xprt_ops svc_tcp_ops = {
 	.xpo_recvfrom = svc_tcp_recvfrom,
 	.xpo_sendto = svc_tcp_sendto,
+	.xpo_release_rqst = svc_release_skb,
 };
 
 static struct svc_xprt_class svc_tcp_class = {
@@ -1578,7 +1579,7 @@
 	}
 
 	/* release the receive skb before sending the reply */
-	svc_release_skb(rqstp);
+	rqstp->rq_xprt->xpt_ops->xpo_release_rqst(rqstp);
 
 	/* calculate over-all length */
 	xb = & rqstp->rq_res;