SUNRPC: Move the svc_xdr_recvfrom tracepoint again

Commit 156708adf2 ("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 <chuck.lever@oracle.com>
This commit is contained in:
Chuck Lever
2021-01-03 14:39:27 -05:00
parent 51b2ee7d00
commit 5f39d2713b
2 changed files with 56 additions and 9 deletions

View File

@@ -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);