[PATCH v12 05/24] nfsd: fix nfsfh tracepoints to properly handle NULL rqstp

[Mike Snitzer <snitzer@xxxxxxxxxx>]

Fixes stop-gap used in previous commit where caller avoided using
tracepoint if rqstp is NULL.  Instead, have each tracepoint avoid
dereferencing NULL rqstp.

Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
---
 fs/nfsd/nfsfh.c | 12 ++++--------
 fs/nfsd/trace.h | 36 +++++++++++++++++++++---------------
 2 files changed, 25 insertions(+), 23 deletions(-)

diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c
index 19e173187ab9..bae727e65214 100644
--- a/fs/nfsd/nfsfh.c
+++ b/fs/nfsd/nfsfh.c
@@ -195,8 +195,7 @@ static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct net *net,
 
 	error = nfserr_stale;
 	if (IS_ERR(exp)) {
-		if (rqstp)
-			trace_nfsd_set_fh_dentry_badexport(rqstp, fhp, PTR_ERR(exp));
+		trace_nfsd_set_fh_dentry_badexport(rqstp, fhp, PTR_ERR(exp));
 
 		if (PTR_ERR(exp) == -ENOENT)
 			return error;
@@ -244,8 +243,7 @@ static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct net *net,
 						data_left, fileid_type, 0,
 						nfsd_acceptable, exp);
 		if (IS_ERR_OR_NULL(dentry)) {
-			if (rqstp)
-				trace_nfsd_set_fh_dentry_badhandle(rqstp, fhp,
+			trace_nfsd_set_fh_dentry_badhandle(rqstp, fhp,
 					dentry ?  PTR_ERR(dentry) : -ESTALE);
 			switch (PTR_ERR(dentry)) {
 			case -ENOMEM:
@@ -321,8 +319,7 @@ __fh_verify(struct svc_rqst *rqstp,
 	dentry = fhp->fh_dentry;
 	exp = fhp->fh_export;
 
-	if (rqstp)
-		trace_nfsd_fh_verify(rqstp, fhp, type, access);
+	trace_nfsd_fh_verify(net, rqstp, fhp, type, access);
 
 	/*
 	 * We still have to do all these permission checks, even when
@@ -376,8 +373,7 @@ __fh_verify(struct svc_rqst *rqstp,
 	/* Finally, check access permissions. */
 	error = nfsd_permission(cred, exp, dentry, access);
 out:
-	if (rqstp)
-		trace_nfsd_fh_verify_err(rqstp, fhp, type, access, error);
+	trace_nfsd_fh_verify_err(net, rqstp, fhp, type, access, error);
 	if (error == nfserr_stale)
 		nfsd_stats_fh_stale_inc(nn, exp);
 	return error;
diff --git a/fs/nfsd/trace.h b/fs/nfsd/trace.h
index 77bbd23aa150..d49b3c1e3ba9 100644
--- a/fs/nfsd/trace.h
+++ b/fs/nfsd/trace.h
@@ -195,12 +195,13 @@ TRACE_EVENT(nfsd_compound_encode_err,
 
 TRACE_EVENT(nfsd_fh_verify,
 	TP_PROTO(
+		const struct net *net,
 		const struct svc_rqst *rqstp,
 		const struct svc_fh *fhp,
 		umode_t type,
 		int access
 	),
-	TP_ARGS(rqstp, fhp, type, access),
+	TP_ARGS(net, rqstp, fhp, type, access),
 	TP_STRUCT__entry(
 		__field(unsigned int, netns_ino)
 		__sockaddr(server, rqstp->rq_xprt->xpt_remotelen)
@@ -212,12 +213,14 @@ TRACE_EVENT(nfsd_fh_verify,
 		__field(unsigned long, access)
 	),
 	TP_fast_assign(
-		__entry->netns_ino = SVC_NET(rqstp)->ns.inum;
-		__assign_sockaddr(server, &rqstp->rq_xprt->xpt_local,
-		       rqstp->rq_xprt->xpt_locallen);
-		__assign_sockaddr(client, &rqstp->rq_xprt->xpt_remote,
-				  rqstp->rq_xprt->xpt_remotelen);
-		__entry->xid = be32_to_cpu(rqstp->rq_xid);
+		__entry->netns_ino = net->ns.inum;
+		if (rqstp) {
+			__assign_sockaddr(server, &rqstp->rq_xprt->xpt_local,
+					  rqstp->rq_xprt->xpt_locallen);
+			__assign_sockaddr(client, &rqstp->rq_xprt->xpt_remote,
+					  rqstp->rq_xprt->xpt_remotelen);
+		}
+		__entry->xid = rqstp ? be32_to_cpu(rqstp->rq_xid) : 0;
 		__entry->fh_hash = knfsd_fh_hash(&fhp->fh_handle);
 		__entry->inode = d_inode(fhp->fh_dentry);
 		__entry->type = type;
@@ -232,13 +235,14 @@ TRACE_EVENT(nfsd_fh_verify,
 
 TRACE_EVENT_CONDITION(nfsd_fh_verify_err,
 	TP_PROTO(
+		const struct net *net,
 		const struct svc_rqst *rqstp,
 		const struct svc_fh *fhp,
 		umode_t type,
 		int access,
 		__be32 error
 	),
-	TP_ARGS(rqstp, fhp, type, access, error),
+	TP_ARGS(net, rqstp, fhp, type, access, error),
 	TP_CONDITION(error),
 	TP_STRUCT__entry(
 		__field(unsigned int, netns_ino)
@@ -252,12 +256,14 @@ TRACE_EVENT_CONDITION(nfsd_fh_verify_err,
 		__field(int, error)
 	),
 	TP_fast_assign(
-		__entry->netns_ino = SVC_NET(rqstp)->ns.inum;
-		__assign_sockaddr(server, &rqstp->rq_xprt->xpt_local,
-		       rqstp->rq_xprt->xpt_locallen);
-		__assign_sockaddr(client, &rqstp->rq_xprt->xpt_remote,
-				  rqstp->rq_xprt->xpt_remotelen);
-		__entry->xid = be32_to_cpu(rqstp->rq_xid);
+		__entry->netns_ino = net->ns.inum;
+		if (rqstp) {
+			__assign_sockaddr(server, &rqstp->rq_xprt->xpt_local,
+					  rqstp->rq_xprt->xpt_locallen);
+			__assign_sockaddr(client, &rqstp->rq_xprt->xpt_remote,
+					  rqstp->rq_xprt->xpt_remotelen);
+		}
+		__entry->xid = rqstp ? be32_to_cpu(rqstp->rq_xid) : 0;
 		__entry->fh_hash = knfsd_fh_hash(&fhp->fh_handle);
 		if (fhp->fh_dentry)
 			__entry->inode = d_inode(fhp->fh_dentry);
@@ -286,7 +292,7 @@ DECLARE_EVENT_CLASS(nfsd_fh_err_class,
 		__field(int, status)
 	),
 	TP_fast_assign(
-		__entry->xid = be32_to_cpu(rqstp->rq_xid);
+		__entry->xid = rqstp ? be32_to_cpu(rqstp->rq_xid) : 0;
 		__entry->fh_hash = knfsd_fh_hash(&fhp->fh_handle);
 		__entry->status = status;
 	),
-- 
2.44.0