SUNRPC: mark bulk read/write data in xdrbuf

Adds a flag word to the xdrbuf struct which indicates any bulk
disposition of the data. This enables RPC transport providers to
marshal it efficiently/appropriately, and may enable other
optimizations.

Signed-off-by: Tom Talpey <tmt@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/nfs3xdr.c b/fs/nfs/nfs3xdr.c
index 8a225fb..616d326 100644
--- a/fs/nfs/nfs3xdr.c
+++ b/fs/nfs/nfs3xdr.c
@@ -346,6 +346,7 @@
 	replen = (RPC_REPHDRSIZE + auth->au_rslack + NFS3_readres_sz) << 2;
 	xdr_inline_pages(&req->rq_rcv_buf, replen,
 			 args->pages, args->pgbase, count);
+	req->rq_rcv_buf.flags |= XDRBUF_READ;
 	return 0;
 }
 
@@ -367,6 +368,7 @@
 
 	/* Copy the page array */
 	xdr_encode_pages(sndbuf, args->pages, args->pgbase, count);
+	sndbuf->flags |= XDRBUF_WRITE;
 	return 0;
 }