From 5f39d2713bd80e8a3e6d9299930aec8844872c0e Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Sun, 3 Jan 2021 14:39:27 -0500 Subject: [PATCH] SUNRPC: Move the svc_xdr_recvfrom tracepoint again Commit 156708adf2d9 ("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: Chuck Lever --- include/trace/events/sunrpc.h | 61 +++++++++++++++++++++++++++++++---- net/sunrpc/svc_xprt.c | 4 +-- 2 files changed, 56 insertions(+), 9 deletions(-) diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h index 58994e013022..6f89c27265f5 100644 --- a/include/trace/events/sunrpc.h +++ b/include/trace/events/sunrpc.h @@ -1424,13 +1424,13 @@ TRACE_EVENT(rpcb_unregister, ) ); -DECLARE_EVENT_CLASS(svc_xdr_buf_class, +/* Record an xdr_buf containing a fully-formed RPC message */ +DECLARE_EVENT_CLASS(svc_xdr_msg_class, TP_PROTO( - const struct svc_rqst *rqst, const struct xdr_buf *xdr ), - TP_ARGS(rqst, xdr), + TP_ARGS(xdr), TP_STRUCT__entry( __field(u32, xid) @@ -1443,7 +1443,55 @@ DECLARE_EVENT_CLASS(svc_xdr_buf_class, ), TP_fast_assign( - __entry->xid = be32_to_cpu(rqst->rq_xid); + __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( + __be32 xid, + const struct xdr_buf *xdr + ), + + TP_ARGS(xid, 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( + __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); /* diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c index 5fb9164aa690..dcc50ae54550 100644 --- a/net/sunrpc/svc_xprt.c +++ b/net/sunrpc/svc_xprt.c @@ -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);