RDMA/rtrs: Use flexible array for client path stats

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.

Link: https://patch.msgid.link/r/20260511041812.378030-1-rosenp@gmail.com
Assisted-by: Codex:GPT-5.5
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Acked-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

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 @@ close_path:
 	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 {