[PATCH RFC 06/10] SUNRPC: Clean up rpc_verify_header()

[Chuck Lever <chuck.lever@oracle.com>]

- Recover some instruction count because I'm about to introduce a
  few xdr_inline_decode call sites
- Replace dprintk() call sites with trace points
- Reduce the hot path so it fits in fewer cachelines

I've also renamed it rpc_decode_header() to match everything else
in the RPC client.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 include/trace/events/sunrpc.h |   52 ++++++++++
 net/sunrpc/clnt.c             |  223 ++++++++++++++++++-----------------------
 2 files changed, 148 insertions(+), 127 deletions(-)

diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h
index 2b3f9d1..0531fc4 100644
--- a/include/trace/events/sunrpc.h
+++ b/include/trace/events/sunrpc.h
@@ -241,6 +241,58 @@
 			TP_ARGS(task))
 
 DEFINE_RPC_FAILURE(callhdr);
+DEFINE_RPC_FAILURE(verifier);
+
+DECLARE_EVENT_CLASS(rpc_reply_event,
+
+	TP_PROTO(
+		const struct rpc_task *task
+	),
+
+	TP_ARGS(task),
+
+	TP_STRUCT__entry(
+		__field(unsigned int, task_id)
+		__field(unsigned int, client_id)
+		__field(u32, xid)
+		__string(progname, task->tk_client->cl_program->name)
+		__field(u32, version)
+		__string(procname, rpc_proc_name(task))
+		__string(servername, task->tk_xprt->servername)
+	),
+
+	TP_fast_assign(
+		__entry->task_id = task->tk_pid;
+		__entry->client_id = task->tk_client->cl_clid;
+		__entry->xid = be32_to_cpu(task->tk_rqstp->rq_xid);
+		__assign_str(progname, task->tk_client->cl_program->name)
+		__entry->version = task->tk_client->cl_vers;
+		__assign_str(procname, rpc_proc_name(task))
+		__assign_str(servername, task->tk_xprt->servername)
+	),
+
+	TP_printk("task:%u@%d server=%s xid=0x%08x %sv%d %s",
+		__entry->task_id, __entry->client_id, __get_str(servername),
+		__entry->xid, __get_str(progname), __entry->version,
+		__get_str(procname))
+)
+
+#define DEFINE_RPC_REPLY_EVENT(name)					\
+	DEFINE_EVENT(rpc_reply_event, rpc_##name,			\
+			TP_PROTO(					\
+				const struct rpc_task *task		\
+			),						\
+			TP_ARGS(task))
+
+DEFINE_RPC_REPLY_EVENT(prog_unavail);
+DEFINE_RPC_REPLY_EVENT(prog_mismatch);
+DEFINE_RPC_REPLY_EVENT(proc_unavail);
+DEFINE_RPC_REPLY_EVENT(garbage_args);
+DEFINE_RPC_REPLY_EVENT(unparsable);
+DEFINE_RPC_REPLY_EVENT(mismatch);
+DEFINE_RPC_REPLY_EVENT(stale_creds);
+DEFINE_RPC_REPLY_EVENT(bad_creds);
+DEFINE_RPC_REPLY_EVENT(auth_tooweak);
 
 TRACE_EVENT(rpc_stats_latency,
 
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 83549c4..2461b18 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -79,7 +79,7 @@
 
 static int	rpc_encode_header(struct rpc_task *task,
 				  struct xdr_stream *xdr);
-static __be32	*rpc_verify_header(struct rpc_task *task);
+static __be32	*rpc_decode_header(struct rpc_task *task);
 static int	rpc_ping(struct rpc_clnt *clnt);
 
 static void rpc_register_client(struct rpc_clnt *clnt)
@@ -2292,7 +2292,7 @@ void rpc_force_rebind(struct rpc_clnt *clnt)
 		goto out_retry;
 	}
 
-	p = rpc_verify_header(task);
+	p = rpc_decode_header(task);
 	if (IS_ERR(p)) {
 		if (p == ERR_PTR(-EAGAIN))
 			goto out_retry;
@@ -2308,7 +2308,7 @@ void rpc_force_rebind(struct rpc_clnt *clnt)
 	return;
 out_retry:
 	task->tk_status = 0;
-	/* Note: rpc_verify_header() may have freed the RPC slot */
+	/* Note: rpc_decode_header() may have freed the RPC slot */
 	if (task->tk_rqstp == req) {
 		xdr_free_bvec(&req->rq_rcv_buf);
 		req->rq_reply_bytes_recvd = req->rq_rcv_buf.len = 0;
@@ -2347,164 +2347,133 @@ void rpc_force_rebind(struct rpc_clnt *clnt)
 	return error;
 }
 
-static __be32 *
-rpc_verify_header(struct rpc_task *task)
+static noinline __be32 *
+rpc_decode_header(struct rpc_task *task)
 {
 	struct rpc_clnt *clnt = task->tk_client;
 	struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
 	int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
 	__be32	*p = iov->iov_base;
-	u32 n;
 	int error = -EACCES;
 
-	if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
-		/* RFC-1014 says that the representation of XDR data must be a
-		 * multiple of four bytes
-		 * - if it isn't pointer subtraction in the NFS client may give
-		 *   undefined results
-		 */
-		dprintk("RPC: %5u %s: XDR representation not a multiple of"
-		       " 4 bytes: 0x%x\n", task->tk_pid, __func__,
-		       task->tk_rqstp->rq_rcv_buf.len);
-		error = -EIO;
-		goto out_err;
-	}
+	/* RFC-1014 says that the representation of XDR data must be a
+	 * multiple of four bytes
+	 * - if it isn't pointer subtraction in the NFS client may give
+	 *   undefined results
+	 */
+	if (task->tk_rqstp->rq_rcv_buf.len & 3)
+		goto out_badlen;
 	if ((len -= 3) < 0)
-		goto out_overflow;
+		goto out_unparsable;
 
-	p += 1; /* skip XID */
-	if ((n = ntohl(*p++)) != RPC_REPLY) {
-		dprintk("RPC: %5u %s: not an RPC reply: %x\n",
-			task->tk_pid, __func__, n);
-		error = -EIO;
-		goto out_garbage;
-	}
+	p++;	/* skip XID */
+	if (*p++ != rpc_reply)
+		goto out_unparsable;
+	if (*p++ != rpc_msg_accepted)
+		goto out_msg_denied;
 
-	if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
-		if (--len < 0)
-			goto out_overflow;
-		switch ((n = ntohl(*p++))) {
-		case RPC_AUTH_ERROR:
-			break;
-		case RPC_MISMATCH:
-			dprintk("RPC: %5u %s: RPC call version mismatch!\n",
-				task->tk_pid, __func__);
-			error = -EPROTONOSUPPORT;
-			goto out_err;
-		default:
-			dprintk("RPC: %5u %s: RPC call rejected, "
-				"unknown error: %x\n",
-				task->tk_pid, __func__, n);
-			error = -EIO;
-			goto out_err;
-		}
-		if (--len < 0)
-			goto out_overflow;
-		switch ((n = ntohl(*p++))) {
-		case RPC_AUTH_REJECTEDCRED:
-		case RPC_AUTH_REJECTEDVERF:
-		case RPCSEC_GSS_CREDPROBLEM:
-		case RPCSEC_GSS_CTXPROBLEM:
-			if (!task->tk_cred_retry)
-				break;
-			task->tk_cred_retry--;
-			dprintk("RPC: %5u %s: retry stale creds\n",
-					task->tk_pid, __func__);
-			rpcauth_invalcred(task);
-			/* Ensure we obtain a new XID! */
-			xprt_release(task);
-			task->tk_action = call_reserve;
-			goto out_retry;
-		case RPC_AUTH_BADCRED:
-		case RPC_AUTH_BADVERF:
-			/* possibly garbled cred/verf? */
-			if (!task->tk_garb_retry)
-				break;
-			task->tk_garb_retry--;
-			dprintk("RPC: %5u %s: retry garbled creds\n",
-					task->tk_pid, __func__);
-			task->tk_action = call_encode;
-			goto out_retry;
-		case RPC_AUTH_TOOWEAK:
-			printk(KERN_NOTICE "RPC: server %s requires stronger "
-			       "authentication.\n",
-			       task->tk_xprt->servername);
-			break;
-		default:
-			dprintk("RPC: %5u %s: unknown auth error: %x\n",
-					task->tk_pid, __func__, n);
-			error = -EIO;
-		}
-		dprintk("RPC: %5u %s: call rejected %d\n",
-				task->tk_pid, __func__, n);
-		goto out_err;
-	}
 	p = rpcauth_checkverf(task, p);
-	if (IS_ERR(p)) {
-		error = PTR_ERR(p);
-		dprintk("RPC: %5u %s: auth check failed with %d\n",
-				task->tk_pid, __func__, error);
-		goto out_garbage;		/* bad verifier, retry */
-	}
+	if (IS_ERR(p))
+		goto out_verifier;
+
 	len = p - (__be32 *)iov->iov_base - 1;
 	if (len < 0)
-		goto out_overflow;
-	switch ((n = ntohl(*p++))) {
-	case RPC_SUCCESS:
+		goto out_unparsable;
+	switch (*p++) {
+	case rpc_success:
 		return p;
-	case RPC_PROG_UNAVAIL:
-		dprintk("RPC: %5u %s: program %u is unsupported "
-				"by server %s\n", task->tk_pid, __func__,
-				(unsigned int)clnt->cl_prog,
-				task->tk_xprt->servername);
+	case rpc_prog_unavail:
+		trace_rpc_prog_unavail(task);
 		error = -EPFNOSUPPORT;
 		goto out_err;
-	case RPC_PROG_MISMATCH:
-		dprintk("RPC: %5u %s: program %u, version %u unsupported "
-				"by server %s\n", task->tk_pid, __func__,
-				(unsigned int)clnt->cl_prog,
-				(unsigned int)clnt->cl_vers,
-				task->tk_xprt->servername);
+	case rpc_prog_mismatch:
+		trace_rpc_prog_mismatch(task);
 		error = -EPROTONOSUPPORT;
 		goto out_err;
-	case RPC_PROC_UNAVAIL:
-		dprintk("RPC: %5u %s: proc %s unsupported by program %u, "
-				"version %u on server %s\n",
-				task->tk_pid, __func__,
-				rpc_proc_name(task),
-				clnt->cl_prog, clnt->cl_vers,
-				task->tk_xprt->servername);
+	case rpc_proc_unavail:
+		trace_rpc_proc_unavail(task);
 		error = -EOPNOTSUPP;
 		goto out_err;
-	case RPC_GARBAGE_ARGS:
-		dprintk("RPC: %5u %s: server saw garbage\n",
-				task->tk_pid, __func__);
-		break;			/* retry */
+	case rpc_garbage_args:
+		trace_rpc_garbage_args(task);
+		break;
 	default:
-		dprintk("RPC: %5u %s: server accept status: %x\n",
-				task->tk_pid, __func__, n);
-		/* Also retry */
+		trace_rpc_unparsable(task);
 	}
 
 out_garbage:
 	clnt->cl_stats->rpcgarbage++;
 	if (task->tk_garb_retry) {
 		task->tk_garb_retry--;
-		dprintk("RPC: %5u %s: retrying\n",
-				task->tk_pid, __func__);
 		task->tk_action = call_encode;
-out_retry:
 		return ERR_PTR(-EAGAIN);
 	}
 out_err:
 	rpc_exit(task, error);
-	dprintk("RPC: %5u %s: call failed with error %d\n", task->tk_pid,
-			__func__, error);
 	return ERR_PTR(error);
-out_overflow:
-	dprintk("RPC: %5u %s: server reply was truncated.\n", task->tk_pid,
-			__func__);
+
+out_badlen:
+	trace_rpc_unparsable(task);
+	error = -EIO;
+	goto out_err;
+
+out_unparsable:
+	trace_rpc_unparsable(task);
+	error = -EIO;
 	goto out_garbage;
+
+out_verifier:
+	trace_rpc_bad_verifier(task);
+	error = PTR_ERR(p);
+	goto out_garbage;
+
+out_msg_denied:
+	switch (*p++) {
+	case rpc_auth_error:
+		break;
+	case rpc_mismatch:
+		trace_rpc_mismatch(task);
+		error = -EPROTONOSUPPORT;
+		goto out_err;
+	default:
+		trace_rpc_unparsable(task);
+		error = -EIO;
+		goto out_err;
+	}
+
+	switch (*p++) {
+	case rpc_autherr_rejectedcred:
+	case rpc_autherr_rejectedverf:
+	case rpcsec_gsserr_credproblem:
+	case rpcsec_gsserr_ctxproblem:
+		if (!task->tk_cred_retry)
+			break;
+		task->tk_cred_retry--;
+		trace_rpc_stale_creds(task);
+		rpcauth_invalcred(task);
+		/* Ensure we obtain a new XID! */
+		xprt_release(task);
+		task->tk_action = call_reserve;
+		return ERR_PTR(-EAGAIN);
+	case rpc_autherr_badcred:
+	case rpc_autherr_badverf:
+		/* possibly garbled cred/verf? */
+		if (!task->tk_garb_retry)
+			break;
+		task->tk_garb_retry--;
+		trace_rpc_bad_creds(task);
+		task->tk_action = call_encode;
+		return ERR_PTR(-EAGAIN);
+	case rpc_autherr_tooweak:
+		trace_rpc_auth_tooweak(task);
+		pr_warn("RPC: server %s requires stronger authentication.\n",
+			task->tk_xprt->servername);
+		break;
+	default:
+		trace_rpc_unparsable(task);
+		error = -EIO;
+	}
+	goto out_err;
 }
 
 static void rpcproc_encode_null(struct rpc_rqst *rqstp, struct xdr_stream *xdr,