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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 62980C433EF for ; Wed, 24 Nov 2021 22:28:20 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 93E1E6B0075; Wed, 24 Nov 2021 17:28:04 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 8ECF16B0078; Wed, 24 Nov 2021 17:28:04 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7B4F06B007B; Wed, 24 Nov 2021 17:28:04 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0089.hostedemail.com [216.40.44.89]) by kanga.kvack.org (Postfix) with ESMTP id 6C4746B0075 for ; Wed, 24 Nov 2021 17:28:04 -0500 (EST) Received: from smtpin16.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 36BAD8DA37 for ; Wed, 24 Nov 2021 22:27:54 +0000 (UTC) X-FDA: 78845262468.16.716F877 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf27.hostedemail.com (Postfix) with ESMTP id 7BABC70000B9 for ; Wed, 24 Nov 2021 22:27:52 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id B424A6104F; Wed, 24 Nov 2021 22:27:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1637792872; bh=BKz9QA9JFTJnccEGqHOogfldMgA6v13NFeRxPimPlLk=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=woHezK0AN+uT+ToPYnLfy98/iij0DyElM/2RoJrTntUaLhX+bcelCGpi/e9uUMKK4 SPEwWzOrEemU5eGIExvHugkjtdrsNnwt/qyNhVxvUHwYXA8Olh/IwGdd64nRU9tq80 CvqT+9Vzc7U1G6PGEOmhHEMv6ivqOI9P1KX2tNE8= Date: Wed, 24 Nov 2021 14:27:51 -0800 From: Andrew Morton To: Matthew Wilcox Cc: cgel.zte@gmail.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, chiminghao , Zeal Robot Subject: Re: [PATCH] mm: Use BUG_ON instead of if condition followed by BUG Message-Id: <20211124142751.e48cdcc3aea9e0ef899f4347@linux-foundation.org> In-Reply-To: References: <20211124030849.34998-1-chi.minghao@zte.com.cn> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 7BABC70000B9 Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=woHezK0A; dmarc=none; spf=pass (imf27.hostedemail.com: domain of akpm@linux-foundation.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org X-Stat-Signature: nsjc53nh1goa4bet8b59bos1ue1h1rzk X-HE-Tag: 1637792872-571931 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, 24 Nov 2021 13:23:42 +0000 Matthew Wilcox wrote: > On Wed, Nov 24, 2021 at 03:08:49AM +0000, cgel.zte@gmail.com wrote: > > From: chiminghao > > > > Fix the following coccinelle report: > > ./mm/memory_hotplug.c:2210:2-5: > > WARNING Use BUG_ON instead of if condition followed by BUG. > > What coccinelle script is reporting this? > > > - if (try_remove_memory(start, size)) > > - BUG(); > > + BUG_ON(try_remove_memory(start, size)); > > I really, really, really do not like this. For functions with > side-effects, this is bad style. If it's a pure predicate, then > sure, but this is bad. I don't like it either. Yes, BUG() is special but it's such dangerous practice. I'd vote to change coccinelle.