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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9DA19C2BA4C for ; Mon, 8 Nov 2021 21:19:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8730C613B3 for ; Mon, 8 Nov 2021 21:19:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239992AbhKHVWZ (ORCPT ); Mon, 8 Nov 2021 16:22:25 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49682 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239990AbhKHVVk (ORCPT ); Mon, 8 Nov 2021 16:21:40 -0500 Received: from mail.skyhub.de (mail.skyhub.de [IPv6:2a01:4f8:190:11c2::b:1457]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 24F44C061570; Mon, 8 Nov 2021 13:18:55 -0800 (PST) Received: from zn.tnic (p200300ec2f3311007827e440708b1099.dip0.t-ipconnect.de [IPv6:2003:ec:2f33:1100:7827:e440:708b:1099]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id E3BE71EC051F; Mon, 8 Nov 2021 22:18:52 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1636406333; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=AU7V4fSHGUK4yNvIX3QFWGgL2mpvsQwlJrzk1EYTZE4=; b=HI4wHVqdPFUaTmLfTawRP0YuILjCSvy0XvR7UY6GhjpkLZ7Jcpensq3GPz/wKuSVQPh/ah JjfisFcmsOLL77YybjTfUcF4SOtfsMptjoCY2iNpL/QAVX8IlmhT4tll2zqUciAF4fFC2q GhOxoJIWWV9UKbtfg9ziQ2wDV7UERPU= Date: Mon, 8 Nov 2021 22:18:47 +0100 From: Borislav Petkov To: Alan Stern Cc: Geert Uytterhoeven , LKML , Thomas Gleixner , Arnd Bergmann , Ayush Sawal , Greg Kroah-Hartman , Rohit Maheshwari , Steven Rostedt , Vinay Kumar Yadav , ALSA Development Mailing List , bcm-kernel-feedback-list , Intel Graphics Development , intel-gvt-dev@lists.freedesktop.org, alpha , Linux ARM , linux-clk , Linux Crypto Mailing List , linux-edac@vger.kernel.org, Linux Fbdev development list , linux-hyperv@vger.kernel.org, linux-iio@vger.kernel.org, linux-leds , "open list:BROADCOM NVRAM DRIVER" , Parisc List , Linux PM list , linuxppc-dev , "open list:REMOTE PROCESSOR (REMOTEPROC) SUBSYSTEM" , Linux-Renesas , linux-s390 , scsi , Linux-sh list , linux-staging@lists.linux.dev, linux-tegra , linux-um , USB list , "open list:TENSILICA XTENSA PORT (xtensa)" , netdev , openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux , the arch/x86 maintainers , xen-devel@lists.xenproject.org Subject: Re: [PATCH v0 42/42] notifier: Return an error when callback is already registered Message-ID: References: <20211108101157.15189-1-bp@alien8.de> <20211108101157.15189-43-bp@alien8.de> <20211108205926.GA1678880@rowland.harvard.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20211108205926.GA1678880@rowland.harvard.edu> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 08, 2021 at 03:59:26PM -0500, Alan Stern wrote: > Is there really any reason for returning an error code? For example, is > it anticipated that at some point in the future these registration calls > might fail? > > Currently, the only reason for failing... Right, I believe with not making it return void we're leaving the door open for some, *hypothetical* future return values if we decide we need to return them too, at some point. Yes, I can't think of another fact to state besides that the callback was already registered or return success but who knows what we wanna do in the future... And so if we change them all to void now, I think it'll be a lot more churn to switch back to returning a non-void value and having the callers who choose to handle that value, do so again. So, long story short, keeping the retval - albeit not very useful right now - is probably easier. I hope I'm making some sense here. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette