From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 979CDA47; Mon, 17 Mar 2025 18:39:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742236787; cv=none; b=R3gRkiI2CgWnBzk4UkSYaFUzaKBzVYaifSwLNK4dqfeWbTtk+yuPiWwL1UdLAbwcje/8X56EWHqgMGBt/SOzqugX0un61cv/xQvRafm4DkbYVR6DvNWzAMpYDcPaXWZPsaxZfbIdvQDY14H4WUXWKpZIp1BUoHuM1wQMD2xfvDc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742236787; c=relaxed/simple; bh=vUX45IpvzkZ02AKd/IPVjrW9oSbaLGh6sBQvAFq19HE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=X1n+fY4yIoIc6s1uXvAL/Cd3h4Ka3M5t8K22CB51WJGpFtoi87J69A38ONRbr1LYK5Kyatd9Tnu/YtDoLTdemwCgWiraQyNT1YddFbR1bRdV71WPsMetQWe+rMLr/WUtg2WpXMwhVpwnvK2KuUWTv0aNV2xbkofHpfr0hP+yV4w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jGuuttoH; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="jGuuttoH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DD18EC4CEE3; Mon, 17 Mar 2025 18:39:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1742236787; bh=vUX45IpvzkZ02AKd/IPVjrW9oSbaLGh6sBQvAFq19HE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=jGuuttoHaD6RxL8XyLcH8U/Eze2zBL1LfSMf4UoEBLdE1Qb6R6B+I2ir38qrpN8RT NJUKQcY7FEya0MNZQGnwmHFoiGecAxvcYA/FsGVW5H7Xl8txUn7D7UGnjhbh53evO1 dVo44wh+dEkVYp2d0kdPWEXhsV9UBU0oIM3+VTeB/eMfIFlf9f5ZCCIgNkbSPTSrNt Z0G/pZd1lWIzCw1yBrVcs+dGv9/OW8cUYsXSxn6UGyOKjkxE5JG3IFO2WJYorL0rus bQd8mX53MU3/oIWREW1Zev0HsYRHB8AE3eFqjvygceJfN92Fddnp87GnEbmp+QsDC7 6EEdwMZf75HWw== Date: Mon, 17 Mar 2025 08:39:45 -1000 From: Tejun Heo To: Chen Linxuan Cc: Josef Bacik , Jens Axboe , Wen Tao , cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH RESEND v2] blk-cgroup: improve policy registration error handling Message-ID: References: <3E333A73B6B6DFC0+20250317022924.150907-1-chenlinxuan@uniontech.com> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3E333A73B6B6DFC0+20250317022924.150907-1-chenlinxuan@uniontech.com> On Mon, Mar 17, 2025 at 10:29:24AM +0800, Chen Linxuan wrote: > 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 Thanks. -- tejun