From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EA08FC7619A for ; Wed, 12 Apr 2023 08:04:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229875AbjDLIEX (ORCPT ); Wed, 12 Apr 2023 04:04:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48756 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229477AbjDLIEU (ORCPT ); Wed, 12 Apr 2023 04:04:20 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DBA4B4EE8; Wed, 12 Apr 2023 01:04:19 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 7437C62F40; Wed, 12 Apr 2023 08:04:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D85F1C433D2; Wed, 12 Apr 2023 08:04:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1681286658; bh=M4jm0qcEHwHN2rg4cpI8iL/HUSBE5oILgTN4CgEI91E=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=PQU6x5s4Rz7n21TaZgbEDSkM2Eo3fLV/ykDjS4alLCLmzcGLs0Hynv2HRltrKfQ6j +rS9dQFHZqDDhZDp3EcTZWedICmjan0GAKnRPAHbzqywfRC7mY1KReenOZEMnXqwZ6 GJ7WQswzCIhBKBX9mFPmXuL4TTFQ8cQMBT8bgqDTzntsjmr083r0Dpee4jbLPaK0RJ 0VHMpgpTa7dyf9Hl3P3cCtWOPa/+O+L8G05s2FJdFzAoqVeYgnYPZVUYTjQ+U1PCHm B12jlctvn4D7JZNmomMAzq0pz8eYCARUDgg8+bx348Sk/Rn1wgug+4YoNBrRvrHGq9 5eVGDLUBcHJmw== Message-ID: <9a92e541-cf98-4ac5-c181-4a6ba76d08f8@kernel.org> Date: Wed, 12 Apr 2023 17:04:16 +0900 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.9.1 Subject: Re: [PATCH] zonefs: remove unnecessary kobject_del() Content-Language: en-US To: Yangtao Li , Naohiro Aota , Johannes Thumshirn , Greg KH Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org References: <20230412031904.13739-1-frank.li@vivo.com> From: Damien Le Moal Organization: Western Digital Research In-Reply-To: <20230412031904.13739-1-frank.li@vivo.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 4/12/23 12:19, Yangtao Li wrote: > kobject_put() actually covers kobject removal automatically, which is > single stage removal. So kill kobject_del() directly. > > Signed-off-by: Yangtao Li > --- > fs/zonefs/sysfs.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/fs/zonefs/sysfs.c b/fs/zonefs/sysfs.c > index 8ccb65c2b419..a535bdea1097 100644 > --- a/fs/zonefs/sysfs.c > +++ b/fs/zonefs/sysfs.c > @@ -113,7 +113,6 @@ void zonefs_sysfs_unregister(struct super_block *sb) > if (!sbi || !sbi->s_sysfs_registered) > return; > > - kobject_del(&sbi->s_kobj); > kobject_put(&sbi->s_kobj); > wait_for_completion(&sbi->s_kobj_unregister); > } What I am not sure about here is that if CONFIG_DEBUG_KOBJECT_RELEASE is enabled, the kobj release is delayed, so the kobject will stay in sysfs potentially after the umount() returns. Not exactly nice as that potentially create races in user space... Not 100% sure though. Greg ? Any thoughts on this ?