From nobody Thu Oct 2 13:03:22 2025 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 012FD248861; Wed, 17 Sep 2025 06:20:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.51 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758090011; cv=none; b=CXV3USiT+kER/gEzRwtXGqBOKpCMmazWwZjtaBU3YTOqmr7x9oFLwcIXyaTaghg5AsCvTyjsBSCMfHEf6UCFh6BtgqXfZ2J2ie57brN+D3DEfqXOpeJpBsau3+uX36vRfApoQdrS28GdeivBiHjWhrzbCBQfeXxjb4MXdSytQAM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758090011; c=relaxed/simple; bh=A3WpJYfVNdnSgFxNP8tuvoSGBsfYDIXMX0wHSJx7+Ig=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=hWwCtHTljyyPsek4rBnOkJiNWEhxzk94WZ6X3A/gAthwBtJ+L8EAeSNZBfqvST8R7puZgLQGbCtSmqEVQRxWzneQ6iU8Lemp8nsmCluvU23bofgMDb/kovqU5KvmUTuRgDQAAfPoFKokI38FnjVQY2LPWR0yzUbLfz5BCd80xj8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=pass smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.93.142]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTPS id 4cRTCD4CP7zYQvWm; Wed, 17 Sep 2025 14:20:08 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.128]) by mail.maildlp.com (Postfix) with ESMTP id 3300B1A0902; Wed, 17 Sep 2025 14:20:07 +0800 (CST) Received: from hulk-vt.huawei.com (unknown [10.67.174.121]) by APP4 (Coremail) with SMTP id gCh0CgCn74sNU8pos3slCw--.39134S3; Wed, 17 Sep 2025 14:20:07 +0800 (CST) From: Chen Ridong To: longman@redhat.com, tj@kernel.org, hannes@cmpxchg.org, mkoutny@suse.com Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, lujialin4@huawei.com, chenridong@huawei.com Subject: [PATCH -next 01/11] cpuset: move the root cpuset write check earlier Date: Wed, 17 Sep 2025 06:04:44 +0000 Message-Id: <20250917060454.2885698-2-chenridong@huaweicloud.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20250917060454.2885698-1-chenridong@huaweicloud.com> References: <20250917060454.2885698-1-chenridong@huaweicloud.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: gCh0CgCn74sNU8pos3slCw--.39134S3 X-Coremail-Antispam: 1UD129KBjvJXoW7uFWUKr47Xw43tF45AFy7ZFb_yoW8Ar4rpF 4UC3yUJrW5XF1UCws7XrZF934rKw1rJFyDtan7Kw1rCF9IyF4jkFy7XwnIyry5GryDCF4U Xa9I9rWj9a1DtFDanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUU9Kb4IE77IF4wAFF20E14v26ryj6rWUM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUGw A2048vs2IY020Ec7CjxVAFwI0_JFI_Gr1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxS w2x7M28EF7xvwVC0I7IYx2IY67AKxVWDJVCq3wA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxV W8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E14v2 6rxl6s0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMc Ij6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_ Jr0_Gr1lF7xvr2IYc2Ij64vIr41lc7CjxVAaw2AFwI0_JF0_Jw1l42xK82IYc2Ij64vIr4 1l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8GjcxK 67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r1q6r43MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI 8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r4j6F4UMIIF0xvE42xK8VAv wI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWUJVW8JwCI42IY6I8E87Iv6xkF7I0E14 v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjxU7qjgUUUUU X-CM-SenderInfo: hfkh02xlgr0w46kxt4xhlfz01xgou0bp/ Content-Type: text/plain; charset="utf-8" From: Chen Ridong The 'cpus' or 'mems' lists of the top_cpuset cannot be modified. This check can be moved before acquiring any locks as a common code block to improve efficiency and maintainability. Signed-off-by: Chen Ridong Reviewed-by: Waiman Long --- kernel/cgroup/cpuset.c | 17 ++++------------- 1 file changed, 4 insertions(+), 13 deletions(-) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 0d41b4993f8c..819adf4fd591 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -2338,10 +2338,6 @@ static int update_cpumask(struct cpuset *cs, struct = cpuset *trialcs, bool force =3D false; int old_prs =3D cs->partition_root_state; =20 - /* top_cpuset.cpus_allowed tracks cpu_active_mask; it's read-only */ - if (cs =3D=3D &top_cpuset) - return -EACCES; - /* * An empty cpus_allowed is ok only if the cpuset has no tasks. * Since cpulist_parse() fails on an empty mask, we special case @@ -2802,15 +2798,6 @@ static int update_nodemask(struct cpuset *cs, struct= cpuset *trialcs, { int retval; =20 - /* - * top_cpuset.mems_allowed tracks node_stats[N_MEMORY]; - * it's read-only - */ - if (cs =3D=3D &top_cpuset) { - retval =3D -EACCES; - goto done; - } - /* * An empty mems_allowed is ok iff there are no tasks in the cpuset. * Since nodelist_parse() fails on an empty mask, we special case @@ -3280,6 +3267,10 @@ ssize_t cpuset_write_resmask(struct kernfs_open_file= *of, struct cpuset *trialcs; int retval =3D -ENODEV; =20 + /* root is read-only */ + if (cs =3D=3D &top_cpuset) + return -EACCES; + buf =3D strstrip(buf); cpuset_full_lock(); if (!is_cpuset_online(cs)) --=20 2.34.1