From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932384AbdJXIst (ORCPT ); Tue, 24 Oct 2017 04:48:49 -0400 Received: from shards.monkeyblade.net ([184.105.139.130]:57734 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751831AbdJXIsp (ORCPT ); Tue, 24 Oct 2017 04:48:45 -0400 Date: Tue, 24 Oct 2017 17:48:42 +0900 (KST) Message-Id: <20171024.174842.272234711073180328.davem@davemloft.net> To: herbert@gondor.apana.org.au Cc: garsilva@embeddedor.com, steffen.klassert@secunet.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] net: xfrm_user: use BUG_ON instead of if condition followed by BUG From: David Miller In-Reply-To: <20171024035320.GA29795@gondor.apana.org.au> References: <20171024032508.GC28462@gondor.apana.org.au> <20171023225043.Horde.R0FvJkHEmPPjnRNzKMOrPb3@gator4166.hostgator.com> <20171024035320.GA29795@gondor.apana.org.au> X-Mailer: Mew version 6.7 on Emacs 25.3 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Tue, 24 Oct 2017 01:48:45 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Herbert Xu Date: Tue, 24 Oct 2017 11:53:20 +0800 > No your patch makes it worse. The original construct makes it > clear that the conditional is real code and not just some debugging > aid. > > With your patch, real code is now inside BUG_ON. This discussion has happened before. But I'll explain the conclusion here for your benefit. BUG_ON() is a statement and everything inside of it will always execute. BUG_ON() is always preferred because it allows arch specific code to pass the conditional result properly into inline asm and builtins for optimal code generation.