Commit 5f39d271 authored by Chuck Lever's avatar Chuck Lever
Browse files

SUNRPC: Move the svc_xdr_recvfrom tracepoint again 



Commit 156708ad ("SUNRPC: Move the svc_xdr_recvfrom()
tracepoint") tried to capture the correct XID in the trace record,
but this line in svc_recv:

	rqstp->rq_xid = svc_getu32(&rqstp->rq_arg.head[0]);

alters the size of rq_arg.head[0].iov_len. The tracepoint records
the correct XID but an incorrect value for the length of the
xdr_buf's head.

To keep the trace callsites simple, I've created two trace classes.
One assumes the xdr_buf contains a full RPC message, and the XID
can be extracted from it. The other assumes the contents of the
xdr_buf are arbitrary, and the xid will be provided by the caller.

Currently there is only one user of each class, but I expect we will
need a few more tracepoints using each class as time goes on.

Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
parent 51b2ee7d

include/trace/events/sunrpc.h

+53 −6
Original line number Diff line number Diff line
@@ -1424,13 +1424,61 @@ TRACE_EVENT(rpcb_unregister, 
	)

);



/* Record an xdr_buf containing a fully-formed RPC message */

DECLARE_EVENT_CLASS(svc_xdr_msg_class,

	TP_PROTO(

		const struct xdr_buf *xdr

	),



	TP_ARGS(xdr),



	TP_STRUCT__entry(

		__field(u32, xid)

		__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(

		__be32 *p = (__be32 *)xdr->head[0].iov_base;



		__entry->xid = be32_to_cpu(*p);

		__entry->head_base = p;

		__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("xid=0x%08x head=[%p,%zu] page=%u tail=[%p,%zu] len=%u",

		__entry->xid,

		__entry->head_base, __entry->head_len, __entry->page_len,

		__entry->tail_base, __entry->tail_len, __entry->msg_len

	)

);



#define DEFINE_SVCXDRMSG_EVENT(name)					\

		DEFINE_EVENT(svc_xdr_msg_class,				\

				svc_xdr_##name,				\

				TP_PROTO(				\

					const struct xdr_buf *xdr	\

				),					\

				TP_ARGS(xdr))



DEFINE_SVCXDRMSG_EVENT(recvfrom);



/* Record an xdr_buf containing arbitrary data, tagged with an XID */

DECLARE_EVENT_CLASS(svc_xdr_buf_class,

	TP_PROTO(

		const struct svc_rqst *rqst,

		__be32 xid,

		const struct xdr_buf *xdr

	),



	TP_ARGS(rqst, xdr),

	TP_ARGS(xid, xdr),



	TP_STRUCT__entry(

		__field(u32, xid)
@@ -1443,7 +1491,7 @@ DECLARE_EVENT_CLASS(svc_xdr_buf_class, 
	),



	TP_fast_assign(

		__entry->xid = be32_to_cpu(rqst->rq_xid);

		__entry->xid = be32_to_cpu(xid);

		__entry->head_base = xdr->head[0].iov_base;

		__entry->head_len = xdr->head[0].iov_len;

		__entry->tail_base = xdr->tail[0].iov_base;
@@ -1463,12 +1511,11 @@ DECLARE_EVENT_CLASS(svc_xdr_buf_class, 
		DEFINE_EVENT(svc_xdr_buf_class,				\

				svc_xdr_##name,				\

				TP_PROTO(				\

					const struct svc_rqst *rqst,	\

					__be32 xid,			\

					const struct xdr_buf *xdr	\

				),					\

				TP_ARGS(rqst, xdr))

				TP_ARGS(xid, xdr))



DEFINE_SVCXDRBUF_EVENT(recvfrom);

DEFINE_SVCXDRBUF_EVENT(sendto);



/*

net/sunrpc/svc_xprt.c

+2 −2
Original line number Diff line number Diff line
@@ -857,6 +857,7 @@ int svc_recv(struct svc_rqst *rqstp, long timeout) 
	err = -EAGAIN;

	if (len <= 0)

		goto out_release;

	trace_svc_xdr_recvfrom(&rqstp->rq_arg);



	clear_bit(XPT_OLD, &xprt->xpt_flags);
@@ -866,7 +867,6 @@ int svc_recv(struct svc_rqst *rqstp, long timeout) 


	if (serv->sv_stats)

		serv->sv_stats->netcnt++;

	trace_svc_xdr_recvfrom(rqstp, &rqstp->rq_arg);

	return len;

out_release:

	rqstp->rq_res.len = 0;
@@ -904,7 +904,7 @@ int svc_send(struct svc_rqst *rqstp) 
	xb->len = xb->head[0].iov_len +

		xb->page_len +

		xb->tail[0].iov_len;

	trace_svc_xdr_sendto(rqstp, xb);

	trace_svc_xdr_sendto(rqstp->rq_xid, xb);

	trace_svc_stats_latency(rqstp);



	len = xprt->xpt_ops->xpo_sendto(rqstp);