[PATCH v2 1/4] sunrpc: add per-netns per-procedure call counts to svc_stat

[Jeff Layton]

The existing per-procedure call counts live in global
svc_version->vs_count[] arrays which are not network-namespace-aware.
Add per-netns equivalents in struct svc_stat so the upcoming netlink
stats interface can return namespace-scoped statistics.

Add a vs_count pointer array to struct svc_stat, along with
svc_stat_alloc_counts() and svc_stat_free_counts() helpers to manage
per-version percpu call count arrays.

Increment the per-net counter alongside the global one in
svc_generic_init_request(). Call the alloc/free helpers from
nfsd_net_init() and nfsd_net_exit().

Assisted-by: Claude:claude-opus-4-6
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
---
 fs/nfsd/nfsctl.c             |  8 ++++++-
 include/linux/sunrpc/stats.h |  6 +++++
 net/sunrpc/stats.c           | 54 ++++++++++++++++++++++++++++++++++++++++++++
 net/sunrpc/svc.c             |  7 ++++++
 4 files changed, 74 insertions(+), 1 deletion(-)

diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 468aad8c3af9..3aaa67b322d5 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -2445,9 +2445,12 @@ static __net_init int nfsd_net_init(struct net *net)
 
 	memset(&nn->nfsd_svcstats, 0, sizeof(nn->nfsd_svcstats));
 	nn->nfsd_svcstats.program = &nfsd_programs[0];
+	retval = svc_stat_alloc_counts(&nn->nfsd_svcstats);
+	if (retval)
+		goto out_proc_error;
 	if (!nfsd_proc_stat_init(net)) {
 		retval = -ENOMEM;
-		goto out_proc_error;
+		goto out_svcstats_error;
 	}
 
 	for (i = 0; i < sizeof(nn->nfsd_versions); i++)
@@ -2465,6 +2468,8 @@ static __net_init int nfsd_net_init(struct net *net)
 #endif
 	return 0;
 
+out_svcstats_error:
+	svc_stat_free_counts(&nn->nfsd_svcstats);
 out_proc_error:
 	percpu_counter_destroy_many(nn->counter, NFSD_STATS_COUNTERS_NUM);
 out_repcache_error:
@@ -2505,6 +2510,7 @@ static __net_exit void nfsd_net_exit(struct net *net)
 	kfree_sensitive(nn->fh_key);
 	nfsd_net_cb_shutdown(nn);
 	nfsd_proc_stat_shutdown(net);
+	svc_stat_free_counts(&nn->nfsd_svcstats);
 	percpu_counter_destroy_many(nn->counter, NFSD_STATS_COUNTERS_NUM);
 	nfsd_idmap_shutdown(net);
 	nfsd_export_shutdown(net);
diff --git a/include/linux/sunrpc/stats.h b/include/linux/sunrpc/stats.h
index 3ce1550d1beb..087ade905e29 100644
--- a/include/linux/sunrpc/stats.h
+++ b/include/linux/sunrpc/stats.h
@@ -37,9 +37,15 @@ struct svc_stat {
 				rpcbadfmt,
 				rpcbadauth,
 				rpcbadclnt;
+
+	/* Per-version per-procedure call counts (per-cpu, per-netns) */
+	unsigned long __percpu	**vs_count;
 };
 
 struct net;
+int			svc_stat_alloc_counts(struct svc_stat *statp);
+void			svc_stat_free_counts(struct svc_stat *statp);
+
 #ifdef CONFIG_PROC_FS
 int			rpc_proc_init(struct net *);
 void			rpc_proc_exit(struct net *);
diff --git a/net/sunrpc/stats.c b/net/sunrpc/stats.c
index 7093e18ac26c..5bcecd2919b1 100644
--- a/net/sunrpc/stats.c
+++ b/net/sunrpc/stats.c
@@ -116,6 +116,60 @@ void svc_seq_show(struct seq_file *seq, const struct svc_stat *statp)
 }
 EXPORT_SYMBOL_GPL(svc_seq_show);
 
+/**
+ * svc_stat_alloc_counts - allocate per-netns per-version call count arrays
+ * @statp: svc_stat whose vs_count arrays should be allocated
+ *
+ * statp->program must be set before calling this.
+ *
+ * Returns zero on success, or a negative errno otherwise.
+ */
+int svc_stat_alloc_counts(struct svc_stat *statp)
+{
+	struct svc_program *prog = statp->program;
+	unsigned int i;
+
+	statp->vs_count = kcalloc(prog->pg_nvers,
+				  sizeof(unsigned long __percpu *),
+				  GFP_KERNEL);
+	if (!statp->vs_count)
+		return -ENOMEM;
+
+	for (i = 0; i < prog->pg_nvers; i++) {
+		if (!prog->pg_vers[i])
+			continue;
+		statp->vs_count[i] = __alloc_percpu(prog->pg_vers[i]->vs_nproc *
+					    sizeof(unsigned long),
+					    sizeof(unsigned long));
+		if (!statp->vs_count[i])
+			goto err;
+	}
+	return 0;
+err:
+	svc_stat_free_counts(statp);
+	return -ENOMEM;
+}
+EXPORT_SYMBOL_GPL(svc_stat_alloc_counts);
+
+/**
+ * svc_stat_free_counts - free per-netns per-version call count arrays
+ * @statp: svc_stat whose vs_count arrays should be freed
+ */
+void svc_stat_free_counts(struct svc_stat *statp)
+{
+	struct svc_program *prog = statp->program;
+	unsigned int i;
+
+	if (!statp->vs_count)
+		return;
+
+	for (i = 0; i < prog->pg_nvers; i++)
+		free_percpu(statp->vs_count[i]);
+	kfree(statp->vs_count);
+	statp->vs_count = NULL;
+}
+EXPORT_SYMBOL_GPL(svc_stat_free_counts);
+
 /**
  * rpc_alloc_iostats - allocate an rpc_iostats structure
  * @clnt: RPC program, version, and xprt
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index ae9ec4bf34f7..bf7c57cbfa3d 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -1375,6 +1375,13 @@ svc_generic_init_request(struct svc_rqst *rqstp,
 	/* Bump per-procedure stats counter */
 	this_cpu_inc(versp->vs_count[rqstp->rq_proc]);
 
+	/* Bump per-net per-procedure stats counter */
+	if (rqstp->rq_server->sv_stats &&
+	    rqstp->rq_server->sv_stats->vs_count &&
+	    rqstp->rq_server->sv_stats->vs_count[rqstp->rq_vers])
+		this_cpu_inc(rqstp->rq_server->sv_stats->vs_count
+				[rqstp->rq_vers][rqstp->rq_proc]);
+
 	ret->dispatch = versp->vs_dispatch;
 	return rpc_success;
 err_bad_vers:

-- 
2.54.0