[PATCH] RDMA/rtrs: Use flexible array for client path stats

[Rosen Penev <rosenp@gmail.com>]

Store the client path statistics in the RTRS client path allocation
instead of allocating them separately.

This ties the stats lifetime directly to the path and removes a separate
allocation failure path. Keep freeing the per-CPU stats data separately,
but do not free the embedded stats object from error paths or the stats
kobject release handler.

Assisted-by: Codex:GPT-5.5
Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
 drivers/infiniband/ulp/rtrs/rtrs-clt-sysfs.c |  2 --
 drivers/infiniband/ulp/rtrs/rtrs-clt.c       | 13 ++-----------
 drivers/infiniband/ulp/rtrs/rtrs-clt.h       |  2 +-
 3 files changed, 3 insertions(+), 14 deletions(-)

diff --git a/drivers/infiniband/ulp/rtrs/rtrs-clt-sysfs.c b/drivers/infiniband/ulp/rtrs/rtrs-clt-sysfs.c
index 287e0ea43287..f8b833bd81ad 100644
--- a/drivers/infiniband/ulp/rtrs/rtrs-clt-sysfs.c
+++ b/drivers/infiniband/ulp/rtrs/rtrs-clt-sysfs.c
@@ -37,8 +37,6 @@ static void rtrs_clt_path_stats_release(struct kobject *kobj)
 	stats = container_of(kobj, struct rtrs_clt_stats, kobj_stats);
 
 	free_percpu(stats->pcpu_stats);
-
-	kfree(stats);
 }
 
 static struct kobj_type ktype_stats = {
diff --git a/drivers/infiniband/ulp/rtrs/rtrs-clt.c b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
index e351552733df..d34d7e5f34d6 100644
--- a/drivers/infiniband/ulp/rtrs/rtrs-clt.c
+++ b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
@@ -1536,7 +1536,7 @@ static struct rtrs_clt_path *alloc_path(struct rtrs_clt_sess *clt,
 	int cpu;
 	size_t total_con;
 
-	clt_path = kzalloc_obj(*clt_path);
+	clt_path = kzalloc_flex(*clt_path, stats, 1);
 	if (!clt_path)
 		goto err;
 
@@ -1552,10 +1552,6 @@ static struct rtrs_clt_path *alloc_path(struct rtrs_clt_sess *clt,
 	clt_path->s.con_num = total_con;
 	clt_path->s.irq_con_num = con_num + 1;
 
-	clt_path->stats = kzalloc_obj(*clt_path->stats);
-	if (!clt_path->stats)
-		goto err_free_con;
-
 	mutex_init(&clt_path->init_mutex);
 	uuid_gen(&clt_path->s.uuid);
 	memcpy(&clt_path->s.dst_addr, path->dst,
@@ -1583,7 +1579,7 @@ static struct rtrs_clt_path *alloc_path(struct rtrs_clt_sess *clt,
 
 	clt_path->mp_skip_entry = alloc_percpu(typeof(*clt_path->mp_skip_entry));
 	if (!clt_path->mp_skip_entry)
-		goto err_free_stats;
+		goto err_free_con;
 
 	for_each_possible_cpu(cpu)
 		INIT_LIST_HEAD(per_cpu_ptr(clt_path->mp_skip_entry, cpu));
@@ -1596,8 +1592,6 @@ static struct rtrs_clt_path *alloc_path(struct rtrs_clt_sess *clt,
 
 err_free_percpu:
 	free_percpu(clt_path->mp_skip_entry);
-err_free_stats:
-	kfree(clt_path->stats);
 err_free_con:
 	kfree(clt_path->s.con);
 err_free_path:
@@ -2863,7 +2857,6 @@ struct rtrs_clt_sess *rtrs_clt_open(struct rtrs_clt_ops *ops,
 			list_del_rcu(&clt_path->s.entry);
 			rtrs_clt_close_conns(clt_path, true);
 			free_percpu(clt_path->stats->pcpu_stats);
-			kfree(clt_path->stats);
 			free_path(clt_path);
 			goto close_all_path;
 		}
@@ -2873,7 +2866,6 @@ struct rtrs_clt_sess *rtrs_clt_open(struct rtrs_clt_ops *ops,
 			list_del_rcu(&clt_path->s.entry);
 			rtrs_clt_close_conns(clt_path, true);
 			free_percpu(clt_path->stats->pcpu_stats);
-			kfree(clt_path->stats);
 			free_path(clt_path);
 			goto close_all_path;
 		}
@@ -3166,7 +3158,6 @@ int rtrs_clt_create_path_from_sysfs(struct rtrs_clt_sess *clt,
 	rtrs_clt_remove_path_from_arr(clt_path);
 	rtrs_clt_close_conns(clt_path, true);
 	free_percpu(clt_path->stats->pcpu_stats);
-	kfree(clt_path->stats);
 	free_path(clt_path);
 
 	return err;
diff --git a/drivers/infiniband/ulp/rtrs/rtrs-clt.h b/drivers/infiniband/ulp/rtrs/rtrs-clt.h
index 986239ed2d3b..1305601a6251 100644
--- a/drivers/infiniband/ulp/rtrs/rtrs-clt.h
+++ b/drivers/infiniband/ulp/rtrs/rtrs-clt.h
@@ -142,12 +142,12 @@ struct rtrs_clt_path {
 	u32			flags;
 	struct kobject		kobj;
 	u8			for_new_clt;
-	struct rtrs_clt_stats	*stats;
 	/* cache hca_port and hca_name to display in sysfs */
 	u8			hca_port;
 	char                    hca_name[IB_DEVICE_NAME_MAX];
 	struct list_head __percpu
 				*mp_skip_entry;
+	struct rtrs_clt_stats	stats[];
 };
 
 struct rtrs_clt_sess {
-- 
2.54.0