From patchwork Mon Mar 17 02:29:24 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Chen Linxuan X-Patchwork-Id: 14018594 Received: from smtpbgbr2.qq.com (smtpbgbr2.qq.com [54.207.22.56]) (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 78DEC22F01; Mon, 17 Mar 2025 02:31:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=54.207.22.56 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742178698; cv=none; b=oiip6tr/U9xbu8tFY2mQdU8P0nZYX5xcDJubRNkn97XZAla0yJ0GSr1rUlNDEZvH2HZAwHttaq89eEt4QpeFVwbFnf/gGFM8ughZPBbdLWN/vZLsFPCRrru7HVvBH+vb9CxT3L9QD7VWNCK2VTlZN226NHYavBjbZaqReChplXA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742178698; c=relaxed/simple; bh=UgfxJNs9q+/V4egib8TdG9hry6mBYQ5JsRB8g8YOHV0=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=nFaep+SWej698dwvoL8UxsZQAy9IvibIEbbUwr/ZH+cGi2GPoIaEouE8S/esYGFIcU0Rj0rvyhVYSVe0vf05plqHQ5I1bJUIdm+pBngB6IWXoEuxD7jq8nk6Qju0njqwXt+v/paR9p95S/ZhtQIPwxtcBBVu4n6eBFdeD0uyGKk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=uniontech.com; spf=pass smtp.mailfrom=uniontech.com; dkim=pass (1024-bit key) header.d=uniontech.com header.i=@uniontech.com header.b=eujEPbGH; arc=none smtp.client-ip=54.207.22.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=uniontech.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=uniontech.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=uniontech.com header.i=@uniontech.com header.b="eujEPbGH" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=uniontech.com; s=onoh2408; t=1742178612; bh=3Ep9OXxN57SI8f3T+ZVX5uyeB57BAjZ5iyhA2KEimRc=; h=From:To:Subject:Date:Message-ID:MIME-Version; b=eujEPbGHu2xoiuLVyAqfym6OY2aEfo1/y+VTsgSa4sWnBZ3VjiLJV3Jcd/WT/5SUx rgu1sIqSuduu8THjxYRJFcNY7nNTnhSlfQ7cU9x8uiOnx4nkkQmrShENtHEPKr+TnP huyTBkJPvz9O1AF4Zecu4wcyoQtTUmcw3dZImT+o= X-QQ-mid: bizesmtp82t1742178584trdbk4w4 X-QQ-Originating-IP: PfeJu7VBQytMgWIHxuI6OA58c+5IKKd8+cawwIOHxTY= Received: from localhost.localdomain ( [113.57.152.160]) by bizesmtp.qq.com (ESMTP) with id ; Mon, 17 Mar 2025 10:29:42 +0800 (CST) X-QQ-SSF: 0000000000000000000000000000000 X-QQ-GoodBg: 1 X-BIZMAIL-ID: 16559626076117230096 From: Chen Linxuan To: Tejun Heo , Josef Bacik , Jens Axboe Cc: Chen Linxuan , Wen Tao , cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH RESEND v2] blk-cgroup: improve policy registration error handling Date: Mon, 17 Mar 2025 10:29:24 +0800 Message-ID: <3E333A73B6B6DFC0+20250317022924.150907-1-chenlinxuan@uniontech.com> X-Mailer: git-send-email 2.48.1 Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-QQ-SENDSIZE: 520 Feedback-ID: bizesmtp:uniontech.com:qybglogicsvrgz:qybglogicsvrgz5a-1 X-QQ-XMAILINFO: MRY6qckr/MVJxb3HfPNW3ZfnBmjUWM9MGV9dFuk0w/eq/JIaFCYCtdB3 mIks34asbJFtK71dGiZ4otvPa6tpbs84T3O+iyXe9k4/r1rKm1amACL1bMjEtlgq3yswCr6 8VYl9+modzLsiC4bJTi8rM/QfVzNQaduGZtZcmsdb/U34sN/C74aHjh+9CyDhteIWokDNZo 67F06gq/TtB82o/tPaEq9+3jTltgA4/c9H2KIRr58hmxAmCb02eIorzi23AQEB38FqymY5s oidj5szmYrGVpYI7Uk+eRCrmSeMSX45ZJHolqPlMO1bGK4sGpOO5BnQIHev/yuy0CH42aKC VCkvvOKnjbSqbYGfTOlQZYRfwPH9JHaBJjQ8oC8cYOnu26VtQHtIHmHa2d+N9tCZcLbFALe f7tV5JUBNJGwVDmCbALf7GxxRdVsPf+TZQriuN7geyztp0adeYRAgXpEBGEbwSVNYHYgTJI psw4tbq4ECxSAbsqd5OYbmrftmbS6f8JP7wPKumrm4h87gqE1yk3S6p5qvmcbY3Q0ToE8kt RHUZ8fP0xdsgzkhY2iidQDq/ZaOi8oo62tBdsJ7/YhJm8fAtC7bXN9bsJJ1gbrOZBNNA222 5GglTQye6Z390FoXBSlLpiDBrlEqyvxBuR5rq/ZlB9nO3TkSChszqRdJ1E4ZM4aBlteUAIf 6/QSZo071fUbsvAAOp3fMwBI5wvfXCIxnzRC6UTeo+IXSmz0CDmssIX2vspRh0J3p20Ar8V ob235v7KS18bWoem0QeCfhugSNVKw7B9t4zrbxTmjk8Hy/BOiT5JkvzxB1+7GkJSnoKnEtP FZqg18hbdCZ9FpDVAzELTV9bBEtTiy3O8nwMsgZypy7oDZHkyLZZmX5j6+H7zlbCXwebJRG uQEZuaVWaqHfKPh+BPKeWfCTk9p8BvXqSVG9tg1BlWvLUJfbkD6iPTaBZmpVrnXxfoZR0oS y+sbvMr7jmOzFOvAOd1d17iAbFuLh8APAhSPc8nkN+LhhF3+GmTDCin1/ X-QQ-XMRINFO: OD9hHCdaPRBwq3WW+NvGbIU= X-QQ-RECHKSPAM: 0 This patch improve the returned error code of blkcg_policy_register(). 1. Move the validation check for cpd/pd_alloc_fn and cpd/pd_free_fn function pairs to the start of blkcg_policy_register(). This ensures we immediately return -EINVAL if the function pairs are not correctly provided, rather than returning -ENOSPC after locking and unlocking mutexes unnecessarily. Those locks should not contention any problems, as error of policy registration is a super cold path. 2. Return -ENOMEM when cpd_alloc_fn() failed. Co-authored-by: Wen Tao Signed-off-by: Wen Tao Signed-off-by: Chen Linxuan Acked-by: Tejun Heo Reviewed-by: Michal Koutný --- block/blk-cgroup.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 9ed93d91d754..2609f7294427 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -1727,27 +1727,27 @@ int blkcg_policy_register(struct blkcg_policy *pol) struct blkcg *blkcg; int i, ret; + /* + * Make sure cpd/pd_alloc_fn and cpd/pd_free_fn in pairs, and policy + * without pd_alloc_fn/pd_free_fn can't be activated. + */ + if ((!pol->cpd_alloc_fn ^ !pol->cpd_free_fn) || + (!pol->pd_alloc_fn ^ !pol->pd_free_fn)) + return -EINVAL; + mutex_lock(&blkcg_pol_register_mutex); mutex_lock(&blkcg_pol_mutex); /* find an empty slot */ - ret = -ENOSPC; for (i = 0; i < BLKCG_MAX_POLS; i++) if (!blkcg_policy[i]) break; if (i >= BLKCG_MAX_POLS) { pr_warn("blkcg_policy_register: BLKCG_MAX_POLS too small\n"); + ret = -ENOSPC; goto err_unlock; } - /* - * Make sure cpd/pd_alloc_fn and cpd/pd_free_fn in pairs, and policy - * without pd_alloc_fn/pd_free_fn can't be activated. - */ - if ((!pol->cpd_alloc_fn ^ !pol->cpd_free_fn) || - (!pol->pd_alloc_fn ^ !pol->pd_free_fn)) - goto err_unlock; - /* register @pol */ pol->plid = i; blkcg_policy[pol->plid] = pol; @@ -1758,8 +1758,10 @@ int blkcg_policy_register(struct blkcg_policy *pol) struct blkcg_policy_data *cpd; cpd = pol->cpd_alloc_fn(GFP_KERNEL); - if (!cpd) + if (!cpd) { + ret = -ENOMEM; goto err_free_cpds; + } blkcg->cpd[pol->plid] = cpd; cpd->blkcg = blkcg;