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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 223C7C00449 for ; Fri, 5 Oct 2018 11:51:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D926E206B2 for ; Fri, 5 Oct 2018 11:51:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D926E206B2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-wireless-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728301AbeJESts (ORCPT ); Fri, 5 Oct 2018 14:49:48 -0400 Received: from szxga05-in.huawei.com ([45.249.212.191]:13196 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728025AbeJESts (ORCPT ); Fri, 5 Oct 2018 14:49:48 -0400 Received: from DGGEMS404-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id E2820AED6129E; Fri, 5 Oct 2018 19:51:17 +0800 (CST) Received: from [127.0.0.1] (10.177.31.96) by DGGEMS404-HUB.china.huawei.com (10.3.19.204) with Microsoft SMTP Server id 14.3.399.0; Fri, 5 Oct 2018 19:51:19 +0800 Subject: Re: [PATCH] wil6210: fix debugfs_simple_attr.cocci warnings To: Kalle Valo References: <1538737646-118337-1-git-send-email-yuehaibing@huawei.com> <877eiw1wol.fsf@codeaurora.org> CC: Maya Erez , , , , From: YueHaibing Message-ID: <08e22040-6e8d-75d1-c0ec-37818435eeba@huawei.com> Date: Fri, 5 Oct 2018 19:51:18 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: <877eiw1wol.fsf@codeaurora.org> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.31.96] X-CFilter-Loop: Reflected Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org On 2018/10/5 19:04, Kalle Valo wrote: > YueHaibing writes: > >> Use DEFINE_DEBUGFS_ATTRIBUTE rather than DEFINE_SIMPLE_ATTRIBUTE >> for debugfs files. >> >> Semantic patch information: >> Rationale: DEFINE_SIMPLE_ATTRIBUTE + debugfs_create_file() >> imposes some significant overhead as compared to >> DEFINE_DEBUGFS_ATTRIBUTE + debugfs_create_file_unsafe(). >> >> Generated by: scripts/coccinelle/api/debugfs/debugfs_simple_attr.cocci > > Just out of curiosity, what kind of overhead are we talking about here? commit 5103068eaca2 ("debugfs, coccinelle: check for obsolete DEFINE_SIMPLE_ATTRIBUTE() usage") said this: In order to protect against file removal races, debugfs files created via debugfs_create_file() now get wrapped by a struct file_operations at their opening. If the original struct file_operations are known to be safe against removal races by themselves already, the proxy creation may be bypassed by creating the files through debugfs_create_file_unsafe(). In order to help debugfs users who use the common DEFINE_SIMPLE_ATTRIBUTE() + debugfs_create_file() idiom to transition to removal safe struct file_operations, the helper macro DEFINE_DEBUGFS_ATTRIBUTE() has been introduced. >