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DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1766704898; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=HNWA2wy5x9qmESizAoWxNjF5HTjl76WyG9bV89v6wkc=; b=vbIrljY9Mm8NiHjnoyWxvDlzPBU2XDS3DgZXbUz8CnkO/r1IXynRdZ8/R1sxe1r4/n2nhn grLSA4DBmRv8k2SMke7G7nnY2fKRze3XDs+LQhTS4HCHZYnjRzuCWi6jsah7qfHMH6W3nv sqCjwirvPFv+S3Obsz/ngB7fVRGsvVw= From: Shakeel Butt To: Andrew Morton Cc: Johannes Weiner , Michal Hocko , Roman Gushchin , Muchun Song , SeongJae Park , Meta kernel team , linux-mm@kvack.org, cgroups@vger.kernel.org, damon@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH 3/8] memcg: mem_cgroup_get_from_ino() returns NULL on error Date: Thu, 25 Dec 2025 15:21:11 -0800 Message-ID: <20251225232116.294540-4-shakeel.butt@linux.dev> In-Reply-To: <20251225232116.294540-1-shakeel.butt@linux.dev> References: <20251225232116.294540-1-shakeel.butt@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Stat-Signature: no8w3on67f941n6eskgqegqi8o4i6x9a X-Rspam-User: X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: F1302A0002 X-HE-Tag: 1766704899-761391 X-HE-Meta: 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 aZGvJSJw gvwSuhbvLm396RPXM519LUeLy3RPDDU30GtteAgQlMP3fQBJ5sV9HfKR4TGNBW8/vhnKFZ0BFPZRowl9lCibqreWXBnfT558vHfBo+0zEQIQPcm+b7NHpUT+cgcgXt8vPH1JyUWVcHLiCfjifOU3RAbfsMQdcEtbsOk+fN7jPwtMb7K/0/6r0ESFIXQQVwb0qqMgTnO2XOu/mN3sIVgYcg81odiIqrRDPYdpYtkvIi1SHikclU2vswSY+OQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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(). Signed-off-by: Shakeel Butt --- 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 e85816960e38..92beb74482fa 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 20eaee3e97f7..8aaeb8f5c3af 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