[PATCH] RPC: skip over transport-specific heads automatically

 Add a generic mechanism for skipping over transport-specific headers
 when constructing an RPC request.  This removes another "xprt->stream"
 dependency.

 Test-plan:
 Write-intensive workload on a single mount point (try both UDP and
 TCP).

 Signed-off-by: Chuck Lever <cel@netapp.com>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index e73174c..966c456 100644
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -155,6 +155,8 @@
 
 	size_t			max_payload;	/* largest RPC payload size,
 						   in bytes */
+	unsigned int		tsh_size;	/* size of transport specific
+						   header */
 
 	struct rpc_wait_queue	sending;	/* requests waiting to send */
 	struct rpc_wait_queue	resend;		/* requests waiting to resend */
@@ -236,6 +238,11 @@
 void			xprt_release(struct rpc_task *task);
 int			xprt_destroy(struct rpc_xprt *xprt);
 
+static inline u32 *xprt_skip_transport_header(struct rpc_xprt *xprt, u32 *p)
+{
+	return p + xprt->tsh_size;
+}
+
 /*
  * Transport switch helper functions
  */