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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DC8F4C433F5 for ; Mon, 8 Nov 2021 21:19:21 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A21C1610A5 for ; Mon, 8 Nov 2021 21:19:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org A21C1610A5 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=alien8.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.223621.386386 (Exim 4.92) (envelope-from ) id 1mkC2c-0004VF-Va; Mon, 08 Nov 2021 21:18:58 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 223621.386386; Mon, 08 Nov 2021 21:18:58 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1mkC2c-0004V8-SA; Mon, 08 Nov 2021 21:18:58 +0000 Received: by outflank-mailman (input) for mailman id 223621; Mon, 08 Nov 2021 21:18:57 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1mkC2a-0004Uj-5O for xen-devel@lists.xenproject.org; Mon, 08 Nov 2021 21:18:57 +0000 Received: from mail.skyhub.de (mail.skyhub.de [5.9.137.197]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id 798e332d-40d9-11ec-a9d2-d9f7a1cc8784; Mon, 08 Nov 2021 22:18:53 +0100 (CET) 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) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 798e332d-40d9-11ec-a9d2-d9f7a1cc8784 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> 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