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 X-Spam-Level: X-Spam-Status: No, score=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1A34BC2D0EE for ; Tue, 31 Mar 2020 11:08:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DA140207FF for ; Tue, 31 Mar 2020 11:08:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=metafoo.de header.i=@metafoo.de header.b="LjgXcRCT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730575AbgCaLIL (ORCPT ); Tue, 31 Mar 2020 07:08:11 -0400 Received: from www381.your-server.de ([78.46.137.84]:60258 "EHLO www381.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730377AbgCaLIK (ORCPT ); Tue, 31 Mar 2020 07:08:10 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=metafoo.de; s=default2002; h=Content-Transfer-Encoding:Content-Type:In-Reply-To: MIME-Version:Date:Message-ID:From:References:Cc:To:Subject:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=dO+HmymDbjQQciYegqXjO3hF6Swgv/jmvaAxnl+cdp0=; b=LjgXcRCT0WS9V0AIUNR9YYxjkX ULBbNCUOSshQS9sZ9bd9NTlaXNzpHiuX+NqOgKBcXTVxh4PouWS7VRx7/J+SCZwhW/B2Wp2oYy6Z9 Ce9UQlll1XUtETgtwhZ7yDaGnDUTMZmpVbBJzeiTGdPZTuC54sYKzwMylNHsh7q0MnUWqUQtgrzq7 KpJLwnkSrCD2U4jD/QKk/du6wGEj5AjdUd2zX+1GtkgkIxoPUwySCpkrKTwmZgIirZZXarTpava/k Ar/jVU0tZHB3ZMYc/JHkx3azzc1foeO5LiMadvNX+NrDYBv02i8iI5d8l5mZP2bloobbQLMkJP9WW fXP3BjTA==; Received: from sslproxy02.your-server.de ([78.47.166.47]) by www381.your-server.de with esmtpsa (TLSv1.2:DHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89_1) (envelope-from ) id 1jJEkU-0004xI-0l; Tue, 31 Mar 2020 13:08:02 +0200 Received: from [82.135.70.63] (helo=[192.168.178.20]) by sslproxy02.your-server.de with esmtpsa (TLSv1.3:TLS_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1jJEkT-000R1n-JG; Tue, 31 Mar 2020 13:08:01 +0200 Subject: Re: [PATCH 0/2] use DEFINE_DEBUGFS_ATTRIBUTE instead of DEFINE_SIMPLE_ATTRIBUTE To: "Sa, Nuno" , "Ardelean, Alexandru" , "jic23@kernel.org" , "rohitsarkar5398@gmail.com" Cc: "stefan.popa@analog.com" , "zhongjiang@huawei.com" , "linux-iio@vger.kernel.org" , "Bogdan, Dragos" , "pmeerw@pmeerw.net" , "knaack.h@gmx.de" , "Hennerich, Michael" , "linux-kernel@vger.kernel.org" References: <20200328063456.24012-1-rohitsarkar5398@gmail.com> <20200329103818.2fce9529@archlinux> From: Lars-Peter Clausen Message-ID: <74033597-c348-03df-d52f-748bf52c1a12@metafoo.de> Date: Tue, 31 Mar 2020 13:08:00 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Authenticated-Sender: lars@metafoo.de X-Virus-Scanned: Clear (ClamAV 0.102.2/25767/Mon Mar 30 15:08:30 2020) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/31/20 12:58 PM, Sa, Nuno wrote: > Hi Rohit, > >> From: linux-iio-owner@vger.kernel.org On >> Behalf Of Ardelean, Alexandru >> Sent: Montag, 30. März 2020 11:20 >> To: jic23@kernel.org; rohitsarkar5398@gmail.com >> Cc: stefan.popa@analog.com; zhongjiang@huawei.com; linux- >> iio@vger.kernel.org; Bogdan, Dragos ; >> pmeerw@pmeerw.net; knaack.h@gmx.de; Hennerich, Michael >> ; linux-kernel@vger.kernel.org; >> lars@metafoo.de >> Subject: Re: [PATCH 0/2] use DEFINE_DEBUGFS_ATTRIBUTE instead of >> DEFINE_SIMPLE_ATTRIBUTE >> >> On Sun, 2020-03-29 at 10:38 +0100, Jonathan Cameron wrote: >>> On Sat, 28 Mar 2020 12:04:53 +0530 >>> Rohit Sarkar wrote: >>> >>>> The debugfs_create_file_unsafe method does not protect the fops given to >>>> it from file removal. It must be used with DEFINE_DEBUGFS_ATTRIBUTE >>>> which makes the fops aware of the file lifetime. >>>> >>>> Further using DEFINE_DEBUGFS_ATTRIBUTE along with >>>> debugfs_create_file_unsafe significantly reduces the overhead introduced >> by >>>> debugfs_create_file which creates a lifetime managing proxy around each >>>> fops handed in. Refer [1] for more on this. >>>> >>>> Fixes the following warnings reported by coccinelle: >>>> drivers/iio/imu//adis16460.c:126:0-23: WARNING: >> adis16460_flash_count_fops >>>> should be defined with DEFINE_DEBUGFS_ATTRIBUTE >>>> drivers/iio/imu//adis16460.c:108:0-23: WARNING: >> adis16460_product_id_fops >>>> should be defined with DEFINE_DEBUGFS_ATTRIBUTE >>>> drivers/iio/imu//adis16460.c:90:0-23: WARNING: >> adis16460_serial_number_fops >>>> should be defined with DEFINE_DEBUGFS_ATTRIBUTE >>>> drivers/iio/imu//adis16400.c:278:0-23: WARNING: >> adis16400_flash_count_fops >>>> should be defined with DEFINE_DEBUGFS_ATTRIBUTE >>>> drivers/iio/imu//adis16400.c:261:0-23: WARNING: >> adis16400_product_id_fops >>>> should be defined with DEFINE_DEBUGFS_ATTRIBUTE >>>> >>>> [1]: https://lists.gt.net/linux/kernel/2369498 >>>> >>>> Rohit Sarkar (2): >>>> iio: imu: adis16400: use DEFINE_DEBUGFS_ATTRIBUTE instead of >>>> DEFINE_SIMPLE_ATTRIBUTE >>>> iio: imu: adis16460: use DEFINE_DEBUGFS_ATTRIBUTE instead of >>>> DEFINE_SIMPLE_ATTRIBUTE >>>> >>>> drivers/iio/imu/adis16400.c | 4 ++-- >>>> drivers/iio/imu/adis16460.c | 6 +++--- >>>> 2 files changed, 5 insertions(+), 5 deletions(-) >>>> >>> Hi Rohit, >>> >>> You've opened a can of worms with this one. There as a previous series >>> posted doing exactly this change back in 2019 by Zhong Jiang (cc'd) >>> >>> At the time I did a bit of looking into why this had been universally taken >>> up cross tree and turned out there are some potential issues. >>> >>> Alexandru added it to the list of things to test, but I guess it got >>> buried under other work and is still outstanding. >>> >> yep >> my bad; >> will try to make room these days for that old one >> >> > I don't have the exact parts that this patch is touching but I have other parts where this patch > applies and should be same. So, the idea to test this is to read the files in debugfs? Maybe also > some unbind + binding? > > I will try to test this still today... The stress test is to open the debugfs file, then unbind the device and then read from the still open debugfs file. - Lars