From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joe Perches Subject: Re: [PATCH v3 09/11] Input: alps - remove unlikely() from IS_ERR*() condition Date: Sat, 31 Aug 2019 13:32:02 -0700 Message-ID: <762056d9c081c40f3fc760c9af79d6851f0a65e5.camel@perches.com> References: <20190829165025.15750-1-efremov@linux.com> <20190829165025.15750-9-efremov@linux.com> <20190829175039.GA187474@dtor-ws> <20190831152500.eg7xqo5ace6wu427@pali> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20190831152500.eg7xqo5ace6wu427@pali> Sender: linux-kernel-owner@vger.kernel.org To: Pali =?ISO-8859-1?Q?Roh=E1r?= , Denis Efremov Cc: Dmitry Torokhov , linux-kernel@vger.kernel.org, Andrew Morton , linux-input@vger.kernel.org List-Id: linux-input@vger.kernel.org On Sat, 2019-08-31 at 17:25 +0200, Pali Rohár wrote: > On Thursday 29 August 2019 10:50:39 Dmitry Torokhov wrote: > > On Thu, Aug 29, 2019 at 07:50:23PM +0300, Denis Efremov wrote: > > > "unlikely(IS_ERR_OR_NULL(x))" is excessive. IS_ERR_OR_NULL() already uses > > > unlikely() internally. > > > > The keyword here is _internally_. > > > > https://lore.kernel.org/lkml/20190821174857.GD76194@dtor-ws/ > > > > So please no. I think it poor form not to simply restate your original objection from 4 message levels below this link https://lists.gt.net/linux/kernel/2269724 Hm... I do not like this change. If I read code if (unlikely(IS_ERR_OR_NULL(priv->dev3))) then I know that it is really unlikely that condition will be truth and so this is some case of error/exception or something that normally does not happen too much. But if I read code if (IS_ERR_OR_NULL(priv->dev3)) I know nothing about chance that this condition will be truth. Explicit unlikely in previous example give me more information. I alslo think this argument is dubious as it also applies to any IS_ERR and all the unlikely uses have been removed from those.