svcrdma: Create a generic tracing class for displaying xdr_buf layout

This class can be used to create trace points in either the RPC
client or RPC server paths. It simply displays the length of each
part of an xdr_buf, which is useful to determine that the transport
and XDR codecs are operating correctly.

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

1 files changed, 43 insertions, 0 deletions

diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h
index ee993575d2fa..1577223add43 100644
--- a/include/trace/events/sunrpc.h
+++ b/include/trace/events/sunrpc.h
@@ -14,6 +14,49 @@
 #include <linux/net.h>
 #include <linux/tracepoint.h>
 
+DECLARE_EVENT_CLASS(xdr_buf_class,
+	TP_PROTO(
+		const struct xdr_buf *xdr
+	),
+
+	TP_ARGS(xdr),
+
+	TP_STRUCT__entry(
+		__field(const void *, head_base)
+		__field(size_t, head_len)
+		__field(const void *, tail_base)
+		__field(size_t, tail_len)
+		__field(unsigned int, page_len)
+		__field(unsigned int, msg_len)
+	),
+
+	TP_fast_assign(
+		__entry->head_base = xdr->head[0].iov_base;
+		__entry->head_len = xdr->head[0].iov_len;
+		__entry->tail_base = xdr->tail[0].iov_base;
+		__entry->tail_len = xdr->tail[0].iov_len;
+		__entry->page_len = xdr->page_len;
+		__entry->msg_len = xdr->len;
+	),
+
+	TP_printk("head=[%p,%zu] page=%u tail=[%p,%zu] len=%u",
+		__entry->head_base, __entry->head_len, __entry->page_len,
+		__entry->tail_base, __entry->tail_len, __entry->msg_len
+	)
+);
+
+#define DEFINE_XDRBUF_EVENT(name)					\
+		DEFINE_EVENT(xdr_buf_class, name,			\
+				TP_PROTO(				\
+					const struct xdr_buf *xdr	\
+				),					\
+				TP_ARGS(xdr))
+
+DEFINE_XDRBUF_EVENT(xprt_sendto);
+DEFINE_XDRBUF_EVENT(xprt_recvfrom);
+DEFINE_XDRBUF_EVENT(svc_recvfrom);
+DEFINE_XDRBUF_EVENT(svc_sendto);
+
 TRACE_DEFINE_ENUM(RPC_AUTH_OK);
 TRACE_DEFINE_ENUM(RPC_AUTH_BADCRED);
 TRACE_DEFINE_ENUM(RPC_AUTH_REJECTEDCRED);