From 510e12900298ca6dbc474f5f418b21532f2ad101 Mon Sep 17 00:00:00 2001 From: Shakeel Butt Date: Thu, 25 Dec 2025 15:21:11 -0800 Subject: [PATCH] memcg: mem_cgroup_get_from_ino() returns NULL on error Change mem_cgroup_get_from_ino() to return NULL on error instead of ERR_PTR values. This simplifies the API: NULL indicates failure, and a valid pointer indicates success with a CSS reference held that the caller must release via mem_cgroup_put(). Link: https://lkml.kernel.org/r/20251225232116.294540-4-shakeel.butt@linux.dev Signed-off-by: Shakeel Butt Acked-by: Michal Hocko Cc: Axel Rasmussen Cc: Dave Chinner Cc: David Hildenbrand Cc: Johannes Weiner Cc: Lorenzo Stoakes Cc: Muchun Song Cc: Qi Zheng Cc: Roman Gushchin Cc: SeongJae Park Cc: Wei Xu Cc: Yuanchu Xie Signed-off-by: Andrew Morton --- mm/memcontrol.c | 6 ++---- mm/shrinker_debug.c | 2 +- 2 files changed, 3 insertions(+), 5 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index e85816960e38d..92beb74482fae 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3624,17 +3624,15 @@ struct mem_cgroup *mem_cgroup_get_from_ino(unsigned long ino) { struct cgroup *cgrp; struct cgroup_subsys_state *css; - struct mem_cgroup *memcg; + struct mem_cgroup *memcg = NULL; cgrp = cgroup_get_from_id(ino); if (IS_ERR(cgrp)) - return ERR_CAST(cgrp); + return NULL; css = cgroup_get_e_css(cgrp, &memory_cgrp_subsys); if (css) memcg = container_of(css, struct mem_cgroup, css); - else - memcg = ERR_PTR(-ENOENT); cgroup_put(cgrp); diff --git a/mm/shrinker_debug.c b/mm/shrinker_debug.c index 20eaee3e97f7a..8aaeb8f5c3af0 100644 --- a/mm/shrinker_debug.c +++ b/mm/shrinker_debug.c @@ -130,7 +130,7 @@ static ssize_t shrinker_debugfs_scan_write(struct file *file, if (shrinker->flags & SHRINKER_MEMCG_AWARE) { memcg = mem_cgroup_get_from_ino(ino); - if (!memcg || IS_ERR(memcg)) + if (!memcg) return -ENOENT; if (!mem_cgroup_online(memcg)) { -- 2.47.3