SUNRPC: Use struct xdr_stream when constructing RPC Call header

Modernize and harden the code path that constructs each RPC Call
message.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

1 files changed, 35 insertions, 31 deletions

diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index c4203f6138ef..d6750b7f169a 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -77,7 +77,8 @@ static void	call_timeout(struct rpc_task *task);
 static void	call_connect(struct rpc_task *task);
 static void	call_connect_status(struct rpc_task *task);
 
-static __be32	*rpc_encode_header(struct rpc_task *task);
+static int	rpc_encode_header(struct rpc_task *task,
+				  struct xdr_stream *xdr);
 static __be32	*rpc_verify_header(struct rpc_task *task);
 static int	rpc_ping(struct rpc_clnt *clnt);
 
@@ -1728,10 +1729,7 @@ static void
 rpc_xdr_encode(struct rpc_task *task)
 {
 	struct rpc_rqst	*req = task->tk_rqstp;
-	kxdreproc_t	encode;
-	__be32		*p;
-
-	dprint_status(task);
+	struct xdr_stream xdr;
 
 	xdr_buf_init(&req->rq_snd_buf,
 		     req->rq_buffer,
@@ -1740,18 +1738,13 @@ rpc_xdr_encode(struct rpc_task *task)
 		     req->rq_rbuffer,
 		     req->rq_rcvsize);
 
-	p = rpc_encode_header(task);
-	if (p == NULL)
+	req->rq_snd_buf.head[0].iov_len = 0;
+	xdr_init_encode(&xdr, &req->rq_snd_buf,
+			req->rq_snd_buf.head[0].iov_base, req);
+	if (rpc_encode_header(task, &xdr))
 		return;
 
-	encode = task->tk_msg.rpc_proc->p_encode;
-	if (encode == NULL)
-		return;
-
-	task->tk_status = rpcauth_wrap_req(task, encode, req, p,
-			task->tk_msg.rpc_argp);
-	if (task->tk_status == 0)
-		xprt_request_prepare(req);
+	task->tk_status = rpcauth_wrap_req(task, &xdr);
 }
 
 /*
@@ -1762,6 +1755,7 @@ call_encode(struct rpc_task *task)
 {
 	if (!rpc_task_need_encode(task))
 		goto out;
+	dprint_status(task);
 	/* Encode here so that rpcsec_gss can use correct sequence number. */
 	rpc_xdr_encode(task);
 	/* Did the encode result in an error condition? */
@@ -1779,6 +1773,8 @@ call_encode(struct rpc_task *task)
 			rpc_exit(task, task->tk_status);
 		}
 		return;
+	} else {
+		xprt_request_prepare(task->tk_rqstp);
 	}
 
 	/* Add task to reply queue before transmission to avoid races */
@@ -2322,25 +2318,33 @@ out_retry:
 	}
 }
 
-static __be32 *
-rpc_encode_header(struct rpc_task *task)
+static int
+rpc_encode_header(struct rpc_task *task, struct xdr_stream *xdr)
 {
 	struct rpc_clnt *clnt = task->tk_client;
 	struct rpc_rqst	*req = task->tk_rqstp;
-	__be32		*p = req->rq_svec[0].iov_base;
-
-	/* FIXME: check buffer size? */
-
-	*p++ = req->rq_xid;		/* XID */
-	*p++ = htonl(RPC_CALL);		/* CALL */
-	*p++ = htonl(RPC_VERSION);	/* RPC version */
-	*p++ = htonl(clnt->cl_prog);	/* program number */
-	*p++ = htonl(clnt->cl_vers);	/* program version */
-	*p++ = htonl(task->tk_msg.rpc_proc->p_proc);	/* procedure */
-	p = rpcauth_marshcred(task, p);
-	if (p)
-		req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
-	return p;
+	__be32 *p;
+	int error;
+
+	error = -EMSGSIZE;
+	p = xdr_reserve_space(xdr, RPC_CALLHDRSIZE << 2);
+	if (!p)
+		goto out_fail;
+	*p++ = req->rq_xid;
+	*p++ = rpc_call;
+	*p++ = cpu_to_be32(RPC_VERSION);
+	*p++ = cpu_to_be32(clnt->cl_prog);
+	*p++ = cpu_to_be32(clnt->cl_vers);
+	*p   = cpu_to_be32(task->tk_msg.rpc_proc->p_proc);
+
+	error = rpcauth_marshcred(task, xdr);
+	if (error < 0)
+		goto out_fail;
+	return 0;
+out_fail:
+	trace_rpc_bad_callhdr(task);
+	rpc_exit(task, error);
+	return error;
 }
 
 static __be32 *