From patchwork Thu Feb 13 03:35:45 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chen Linxuan X-Patchwork-Id: 13972754 Received: from smtpbgau2.qq.com (smtpbgau2.qq.com [54.206.34.216]) (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 583C52046A0; Thu, 13 Feb 2025 03:38:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=54.206.34.216 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739417938; cv=none; b=XXrDWgx9cPs1esWfglUIuFTEFNECu5TMTYleFjZCtY6SH8ngdQYhOcapBTp4F0TkIrrW79wyP5uzmREpuoVZl+Ybnf3k1lFUnhb0hgh2mxmkQsDcscfb5/LjhCdAj2QiF8qZyxUQhmTsI9xV+moP6/BVp/4kTz2enUU4p5cJQy4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739417938; c=relaxed/simple; bh=p+GcvKfhlbd+fG5D6B3IdokvI8Xp9YdH8bZih/gPh1I=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=p1PeoAcwfrLy16KzjC2a6WItdiCZCzDdSvGheHV8nVG+0I24n4qhDJZI/bMTLikUyl9Aiui4Qs1NbUogbiYQi7Wj2kApeWsjcn4Ij3mmfzRNysmVY7P2jIFtU2m7PJUpv02D49Jk2HMPjp3wL3h7PDce2axOPILDJ+0f6iBcx+4= 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=IVh9g+s+; arc=none smtp.client-ip=54.206.34.216 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="IVh9g+s+" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=uniontech.com; s=onoh2408; t=1739417883; bh=DpzLx+UrFdmR+jkQpgO8A8x7JmsYNWYQhGlpjJhJR5M=; h=From:To:Subject:Date:Message-ID:MIME-Version; b=IVh9g+s+dRk8CtANBNyANwNLu+FlDKatvvtV/VN9xHkK71SYRHW1g1//9Xp5JzBRG LAOBF/ogqv2YgmFx0UZdVVc56f7Yo8XY1qrmTzAqdfOjONJo7X6jYaCzuyDRONwnXx PJI5dl+GQP/KFYNuoemorQozCUjpQ/qVrYCnnh6g= X-QQ-mid: bizesmtpsz4t1739417858tum0b6v X-QQ-Originating-IP: E02J8M1hUNo1RAW5MZSzzIQwC1uMLOuKXwPzVxe+kTw= Received: from localhost.localdomain ( [113.57.152.160]) by bizesmtp.qq.com (ESMTP) with id ; Thu, 13 Feb 2025 11:37:36 +0800 (CST) X-QQ-SSF: 0000000000000000000000000000000 X-QQ-GoodBg: 1 X-BIZMAIL-ID: 5165016000835809032 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 v2] blk-cgroup: improve policy registration error handling Date: Thu, 13 Feb 2025 11:35:45 +0800 Message-ID: X-Mailer: git-send-email 2.43.0 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: bizesmtpsz:uniontech.com:qybglogicsvrgz:qybglogicsvrgz5a-1 X-QQ-XMAILINFO: NQzH8pzEc5hGZIz7f+biLeNFZJx4hqL9dcYcOUtlNvQ67dLPRnpYzSYx B1xC3lCEJoEoRfpDF7c5sNS67+zTZJXOIWlYIaomy9MbR4re/ZrOfNTtmIG72l0/5tN6L3X yDUqeOld+hDqgBYTVcia3UnWpzPJ8nodc56Zs2sNoNhDcitdl40i5VzSLyw0ClAUQEqIDyW JJ5wgxC4APAE4NfGKeAeOORnw0mX0JD0GFkCrkItCVdudYiU33T9KKB0vpq6xgEqxX6RauJ RmuXgWPnOxzTSlt8Q5hfdTnKJ2nvH/xjGLBl0zOrr9u8Dwavg0Z2gTGRAYQcUgsR1Iz/VD0 spq8ulNbjprlkrgS6aqwmyXAS/X++iECiqn+c0BeHCwVLRl8R7FW9a8FM5zTH06zDfCIpYe SEIYyb5o2kei4dPTO/i8Jtd0jvQxVsig/aSiVRtv5MH6mAo1+wnf7iHhhfAwcorHIR9iXsn Dvg50UoKVGr4zZqGY9pUAJN9fF0EEDS99fBV2kjcZvJ77UVKES2As4H+RvV5L4l7wFnep64 UJAfaU23LCI4kZElWsNngcOCvxFkFn/4KiO3BF2rRxWgMa+1dghfZthZ+8UuQTOXPq73bxQ aKjTrgP5MaNLFEWKxeMOFifI9e2QPCGqM4H+y/+b0MsR7C6BPHsmXpja9tUHaNx7gP2gMny KBcdf39pqO4/PX7JrgJGyEpGuyxPx7hQFx7Ryd2mfvwinlu2qEQgO5gVxihmL9wb2LSzSPH 6l/unLyCaXzkdB6tGIpCT/X6hVwoI6kkrxvAaE65PftoRVJvqBdjZyyZebk0id8jhCBQkfw iI0scPLI43QhOTjMQVOpGMOp8ryivhJ5VHpRFxmhNKMG/C5PYESMd1VaWhoCyA3XPA8GZhf 9GclXzSfNxgjC6z9X6DOaHLo7SQ52qfUE6tA96Us7PUlxNZW51QETjoeDCPRgKWe7MG/NPe g9ghquDWcKUkZwT6iyK7hc1uI56+UbsSYCqdgEKII4lZCIZF2MrmBoiYp X-QQ-XMRINFO: Nq+8W0+stu50PRdwbJxPCL0= 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 Reviewed-by: Yu Kuai --- v1->v2: Also change the return value to -ENOMEM from error path err_free_cpds --- 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;