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=-3.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 A0079C2D0A3 for ; Tue, 3 Nov 2020 07:53:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 54DD8223BD for ; Tue, 3 Nov 2020 07:53:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604389984; bh=jBeI1ygIVS761aJfvPTmZQO2j6AowLY8HbQheRGPKH4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=uWp7koYFngtaXsOdH+nBuNYpXN5stx/glTf4axux4mPtIjvI6qqhqB7g4UiDtD2+j eXJ7sEQhovrDytbv8EZF7pq1taasOfWPlFnEpvy0gOWrnAyb1zs5xl/tCJnFPR3ZTI TimOk9jgk3bhErX3Wu/hVbW6cG3d3zA8FJvfF1zI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727779AbgKCHxD (ORCPT ); Tue, 3 Nov 2020 02:53:03 -0500 Received: from mail.kernel.org ([198.145.29.99]:33540 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725968AbgKCHxD (ORCPT ); Tue, 3 Nov 2020 02:53:03 -0500 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0333822384; Tue, 3 Nov 2020 07:53:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604389982; bh=jBeI1ygIVS761aJfvPTmZQO2j6AowLY8HbQheRGPKH4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=q/kuG9HX3HDi8eIRstpuhogWBJrsS0dSsm9WMzEUw0Kz4GKe0toWL2dAv2lADkT5m dubEJIG44fQxQLMCO4Dd51mouK6PaIWQ5VCr4yfxSJ2/EgaKcOgytIi4LXRhC8jv41 M4wnvs4BYPyxq24/8OYf7KKCYw4HXdFg6n/8fHvs= Date: Tue, 3 Nov 2020 08:53:55 +0100 From: Greg KH To: Christian =?iso-8859-1?Q?K=F6nig?= Cc: Alex Deucher , Deepak R Varma , David Airlie , LKML , Maling list - DRI developers , Melissa Wen , amd-gfx list , Daniel Vetter , Daniel Vetter , Alex Deucher Subject: Re: [PATCH] drm/amdgpu: do not initialise global variables to 0 or NULL Message-ID: <20201103075355.GA2505796@kroah.com> References: <20201102184147.GA42288@localhost> <20201103065324.GD75930@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 02, 2020 at 09:48:25PM +0100, Christian König wrote: > Am 03.11.20 um 07:53 schrieb Greg KH: > > On Mon, Nov 02, 2020 at 09:06:21PM +0100, Christian König wrote: > > > Am 02.11.20 um 20:43 schrieb Alex Deucher: > > > > On Mon, Nov 2, 2020 at 1:42 PM Deepak R Varma wrote: > > > > > Initializing global variable to 0 or NULL is not necessary and should > > > > > be avoided. Issue reported by checkpatch script as: > > > > > ERROR: do not initialise globals to 0 (or NULL). > > > > I agree that this is technically correct, but a lot of people don't > > > > seem to know that so we get a lot of comments about this code for the > > > > variables that are not explicitly set. Seems less confusing to > > > > initialize them even if it not necessary. I don't have a particularly > > > > strong opinion on it however. > > > Agree with Alex. > > > > > > Especially for the module parameters we should have a explicit init value > > > for documentation purposes, even when it is 0. > > Why is this one tiny driver somehow special compared to the entire rest > > of the kernel? (hint, it isn't...) > > And it certainly shouldn't :) > > > Please follow the normal coding style rules, there's no reason to ignore > > them unless you like to constantly reject patches like this that get > > sent to you. > > Yeah, that's a rather good point. > > Not a particular strong opinion on this either, but when something global is > set to 0 people usually do this to emphases that it is important that it is > zero. Again, no, that's not what we have been doing in the kernel for the past 20+ years. If you do not set it to anything, we all know it is important for it to be set to 0. Otherwise we would explicitly set it to something else. And if we don't care, then that too doesn't matter so we let it be 0 by not initializing it, it doesn't matter. I think this very change is what started the whole "kernel janitor" movement all those years ago, because it was easily proven that this simple change saved both time and memory. This shouldn't even be an argument we are having anymore... thanks, greg k-h