[PATCH v1 08/14] SUNRPC: Report short RPC messages via a tracepoint

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

Replace a dprintk call site. The new tracepoint can be left enabled
persistently to capture problems.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 include/trace/events/sunrpc.h |   23 +++++++++++++++++++++++
 net/sunrpc/svc.c              |    3 +--
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h
index 23b0964e0425..3cfdd0ef6600 100644
--- a/include/trace/events/sunrpc.h
+++ b/include/trace/events/sunrpc.h
@@ -1642,6 +1642,29 @@ TRACE_EVENT(svc_process,
 	)
 );
 
+TRACE_EVENT(svc_decode_len_err,
+	TP_PROTO(
+		const struct svc_rqst *rqst,
+		const struct kvec *argv
+	),
+
+	TP_ARGS(rqst, argv),
+
+	TP_STRUCT__entry(
+		__field(size_t, len)
+		__string(addr, rqst->rq_xprt ?
+			 rqst->rq_xprt->xpt_remotebuf : "(null)")
+	),
+
+	TP_fast_assign(
+		__entry->len = argv->iov_len;
+		__assign_str(addr, rqst->rq_xprt ?
+			     rqst->rq_xprt->xpt_remotebuf : "(null)");
+	),
+
+	TP_printk("addr=%s len=%zu", __get_str(addr), __entry->len)
+);
+
 DECLARE_EVENT_CLASS(svc_rqst_event,
 
 	TP_PROTO(
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index 5cfbda94e759..3d95faffe43b 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -1379,8 +1379,7 @@ svc_process_common(struct svc_rqst *rqstp, struct kvec *argv, struct kvec *resv)
 	return 0;
 
 err_short_len:
-	svc_printk(rqstp, "short len %zd, dropping request\n",
-			argv->iov_len);
+	trace_svc_decode_len_err(rqstp, argv);
 	goto close_xprt;
 
 err_bad_rpc: