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>

Author: chucklever

include/linux/sunrpc/auth.h

@@ -131,11 +131,12 @@ struct rpc_credops {
 	void			(*crdestroy)(struct rpc_cred *);
 
 	int			(*crmatch)(struct auth_cred *, struct rpc_cred *, int);
-	__be32 *		(*crmarshal)(struct rpc_task *, __be32 *);
+	int			(*crmarshal)(struct rpc_task *task,
+					     struct xdr_stream *xdr);
 	int			(*crrefresh)(struct rpc_task *);
 	__be32 *		(*crvalidate)(struct rpc_task *, __be32 *);
-	int			(*crwrap_req)(struct rpc_task *, kxdreproc_t,
-						void *, __be32 *, void *);
+	int			(*crwrap_req)(struct rpc_task *task,
+					      struct xdr_stream *xdr);
 	int			(*crunwrap_resp)(struct rpc_task *, kxdrdproc_t,
 						void *, __be32 *, void *);
 	int			(*crkey_timeout)(struct rpc_cred *);
@@ -165,9 +166,13 @@ struct rpc_cred *	rpcauth_lookup_credcache(struct rpc_auth *, struct auth_cred *
 void			rpcauth_init_cred(struct rpc_cred *, const struct auth_cred *, struct rpc_auth *, const struct rpc_credops *);
 struct rpc_cred *	rpcauth_lookupcred(struct rpc_auth *, int);
 void			put_rpccred(struct rpc_cred *);
-__be32 *		rpcauth_marshcred(struct rpc_task *, __be32 *);
+int			rpcauth_marshcred(struct rpc_task *task,
+					  struct xdr_stream *xdr);
 __be32 *		rpcauth_checkverf(struct rpc_task *, __be32 *);
-int			rpcauth_wrap_req(struct rpc_task *task, kxdreproc_t encode, void *rqstp, __be32 *data, void *obj);
+int			rpcauth_wrap_req_encode(struct rpc_task *task,
+						struct xdr_stream *xdr);
+int			rpcauth_wrap_req(struct rpc_task *task,
+					 struct xdr_stream *xdr);
 int			rpcauth_unwrap_resp(struct rpc_task *task, kxdrdproc_t decode, void *rqstp, __be32 *data, void *obj);
 bool			rpcauth_xmit_need_reencode(struct rpc_task *task);
 int			rpcauth_refreshcred(struct rpc_task *);

include/linux/sunrpc/xdr.h

@@ -87,6 +87,12 @@ xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
 #define	xdr_one		cpu_to_be32(1)
 #define	xdr_two		cpu_to_be32(2)
 
+#define	rpc_auth_null	cpu_to_be32(RPC_AUTH_NULL)
+#define	rpc_auth_unix	cpu_to_be32(RPC_AUTH_UNIX)
+#define	rpc_auth_gss	cpu_to_be32(RPC_AUTH_GSS)
+
+#define	rpc_call	cpu_to_be32(RPC_CALL)
+
 #define	rpc_success		cpu_to_be32(RPC_SUCCESS)
 #define	rpc_prog_unavail	cpu_to_be32(RPC_PROG_UNAVAIL)
 #define	rpc_prog_mismatch	cpu_to_be32(RPC_PROG_MISMATCH)

include/trace/events/sunrpc.h

@@ -213,6 +213,35 @@ DECLARE_EVENT_CLASS(rpc_task_queued,
 DEFINE_RPC_QUEUED_EVENT(sleep);
 DEFINE_RPC_QUEUED_EVENT(wakeup);
 
+DECLARE_EVENT_CLASS(rpc_failure,
+
+	TP_PROTO(const struct rpc_task *task),
+
+	TP_ARGS(task),
+
+	TP_STRUCT__entry(
+		__field(unsigned int, task_id)
+		__field(unsigned int, client_id)
+	),
+
+	TP_fast_assign(
+		__entry->task_id = task->tk_pid;
+		__entry->client_id = task->tk_client->cl_clid;
+	),
+
+	TP_printk("task:%u@%u",
+		__entry->task_id, __entry->client_id)
+);
+
+#define DEFINE_RPC_FAILURE(name)					\
+	DEFINE_EVENT(rpc_failure, rpc_bad_##name,			\
+			TP_PROTO(					\
+				const struct rpc_task *task		\
+			),						\
+			TP_ARGS(task))
+
+DEFINE_RPC_FAILURE(callhdr);
+
 TRACE_EVENT(rpc_stats_latency,
 
 	TP_PROTO(

net/sunrpc/auth.c

@@ -756,12 +756,21 @@ put_rpccred(struct rpc_cred *cred)
 }
 EXPORT_SYMBOL_GPL(put_rpccred);
 
-__be32 *
-rpcauth_marshcred(struct rpc_task *task, __be32 *p)
+/**
+ * rpcauth_marshcred - Append RPC credential to end of @xdr
+ * @task: controlling RPC task
+ * @xdr: xdr_stream containing initial portion of RPC Call header
+ *
+ * On success, an appropriate verifier is added to @xdr, @xdr is
+ * updated to point past the verifier, and zero is returned.
+ * Otherwise, @xdr is in an undefined state and a negative errno
+ * is returned.
+ */
+int rpcauth_marshcred(struct rpc_task *task, struct xdr_stream *xdr)
 {
-	struct rpc_cred	*cred = task->tk_rqstp->rq_cred;
+	const struct rpc_credops *ops = task->tk_rqstp->rq_cred->cr_ops;
 
-	return cred->cr_ops->crmarshal(task, p);
+	return ops->crmarshal(task, xdr);
 }
 
 __be32 *
@@ -772,26 +781,37 @@ rpcauth_checkverf(struct rpc_task *task, __be32 *p)
 	return cred->cr_ops->crvalidate(task, p);
 }
 
-static void rpcauth_wrap_req_encode(kxdreproc_t encode, struct rpc_rqst *rqstp,
-				   __be32 *data, void *obj)
+/**
+ * rpcauth_wrap_req_encode - XDR encode the RPC procedure
+ * @task: controlling RPC task
+ * @xdr: stream where on-the-wire bytes are to be marshalled
+ *
+ * On success, @xdr contains the encoded and wrapped message.
+ * Otherwise, @xdr is in an undefined state.
+ */
+int rpcauth_wrap_req_encode(struct rpc_task *task, struct xdr_stream *xdr)
 {
-	struct xdr_stream xdr;
+	kxdreproc_t encode = task->tk_msg.rpc_proc->p_encode;
 
-	xdr_init_encode(&xdr, &rqstp->rq_snd_buf, data, rqstp);
-	encode(rqstp, &xdr, obj);
+	encode(task->tk_rqstp, xdr, task->tk_msg.rpc_argp);
+	return 0;
 }
+EXPORT_SYMBOL_GPL(rpcauth_wrap_req_encode);
 
-int
-rpcauth_wrap_req(struct rpc_task *task, kxdreproc_t encode, void *rqstp,
-		__be32 *data, void *obj)
+/**
+ * rpcauth_wrap_req - XDR encode and wrap the RPC procedure
+ * @task: controlling RPC task
+ * @xdr: stream where on-the-wire bytes are to be marshalled
+ *
+ * On success, @xdr contains the encoded and wrapped message,
+ * and zero is returned. Otherwise, @xdr is in an undefined
+ * state and a negative errno is returned.
+ */
+int rpcauth_wrap_req(struct rpc_task *task, struct xdr_stream *xdr)
 {
-	struct rpc_cred *cred = task->tk_rqstp->rq_cred;
+	const struct rpc_credops *ops = task->tk_rqstp->rq_cred->cr_ops;
 
-	if (cred->cr_ops->crwrap_req)
-		return cred->cr_ops->crwrap_req(task, encode, rqstp, data, obj);
-	/* By default, we encode the arguments normally. */
-	rpcauth_wrap_req_encode(encode, rqstp, data, obj);
-	return 0;
+	return ops->crwrap_req(task, xdr);
 }
 
 static int