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

[Jinpu Wang]

On Mon, May 11, 2026 at 6:18 AM Rosen Penev <rosenp@xxxxxxxxx> wrote:
>
> 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@xxxxxxxxx>
Thx!
Acked-by: Jack Wang <jinpu.wang@xxxxxxxxx>
> ---
>  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
>