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=-7.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 19747C433E6 for ; Tue, 26 Jan 2021 16:14:00 +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 D1B9F20756 for ; Tue, 26 Jan 2021 16:13:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D1B9F20756 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.75266.135473 (Exim 4.92) (envelope-from ) id 1l4QyU-0003Q3-EL; Tue, 26 Jan 2021 16:13:50 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 75266.135473; Tue, 26 Jan 2021 16:13:50 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1l4QyU-0003Pw-BM; Tue, 26 Jan 2021 16:13:50 +0000 Received: by outflank-mailman (input) for mailman id 75266; Tue, 26 Jan 2021 16:13:49 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1l4QyT-0003Pr-7d for xen-devel@lists.xenproject.org; Tue, 26 Jan 2021 16:13:49 +0000 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 3a4139b1-bc25-45e8-af44-f627c272a40f; Tue, 26 Jan 2021 16:13:47 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 19F11AB92; Tue, 26 Jan 2021 16:13:47 +0000 (UTC) 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: 3a4139b1-bc25-45e8-af44-f627c272a40f X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1611677627; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=8RLJLIMLsKavuqFKq7beKULubAhkwt+v1KlfaoupVfA=; b=H+6QXyEp9Rat6/oDIc+imcRVmteDXaA5hT4RwcdkF/qIZS1Ab/oF/sSaMviK4EqTS/5C9V jrwDrzUXWiddx5mYFsz66+/9P9CbuLcWYs9BZhAawU6yr7zJFU7poJ7NC4LGxVscaGlGhC vdt5YWXA9GOjS5S/TGZY7Qq0i/K9ZPc= Subject: Re: [PATCH 1/3] x86/irq: remove duplicated clear_domain_irq_pirq calls To: =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= Cc: Andrew Cooper , Wei Liu , xen-devel@lists.xenproject.org References: <20210126110606.21741-1-roger.pau@citrix.com> <20210126110606.21741-2-roger.pau@citrix.com> <10af3f2a-6f4f-372c-6d9a-c02fc730af4b@suse.com> <20210126160851.3ocxqnkmmxzojrar@Air-de-Roger> From: Jan Beulich Message-ID: <6726c520-bb0d-7ed7-21c9-aca31b6721f5@suse.com> Date: Tue, 26 Jan 2021 17:13:47 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.1 MIME-Version: 1.0 In-Reply-To: <20210126160851.3ocxqnkmmxzojrar@Air-de-Roger> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit On 26.01.2021 17:08, Roger Pau Monné wrote: > On Tue, Jan 26, 2021 at 03:38:27PM +0100, Jan Beulich wrote: >> On 26.01.2021 12:06, Roger Pau Monne wrote: >>> There are two duplicated calls to cleanup_domain_irq_pirq in >>> unmap_domain_pirq. >>> >>> The first one in the for loop will be called with exactly the same >>> arguments as the call placed closer to the loop start. >> >> I'm having trouble figuring out which two instances you refer >> to: To me "first one" and "closer to the start" are two ways >> of expressing the same thing. You don't refer to the call to >> clear_domain_irq_pirq(), do you, when the two calls you >> remove are to cleanup_domain_irq_pirq()? Admittedly quite >> similar names, but entirely different functions. > > Urg, yes, that's impossible to parse sensibly, sorry. > > Also the subject is wrong, should be cleanup_domain_irq_pirq, not > clear_domain_irq_pirq. > > This should instead be: > > "There are two duplicated calls to cleanup_domain_irq_pirq in > unmap_domain_pirq. > > The first removed call to cleanup_domain_irq_pirq will be called with > exactly the same arguments as the previous call placed above it." And which one is "the previous call"? I'm still getting the impression you're mixing up cleanup_domain_irq_pirq() and clear_domain_irq_pirq(). (I guess we need to resort to line numbers in current staging or master, to avoid misunderstandings. Not for the commit message [if any], but for the discussion.) > It's hard to explain this in a commit message. > > Do you agree that the removed calls are duplicated though? I might have > as well missed part of the logic here and be wrong about this. No, for the moment I don't agree yet, because I don't see the redundancy so far. >>> The logic used in the loop seems extremely complex to follow IMO, >>> there are several breaks for exiting the loop, and the index (i) is >>> also updated in different places. >> >> Indeed, and it didn't feel well already back at the time when >> I much extended this to support multi-vector MSI. I simply >> didn't have any good idea how to streamline all of this >> (short of rewriting it altogether, which would have made >> patch review quite difficult). If you have thoughts, I'm all >> ears. > > I would just rewrite it altogether. Code like this is very prone to > cause mistakes in the future IMO. If you want I can try to. I wouldn't mind, but yes, besides review difficulties ... > I guess the problem with this is that we would lose the history of the > code for no functional change. ... this also wouldn't be overly nice (but can be dealt with via a few more steps wading through git history). Jan