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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 39BFFC433EF for ; Sat, 11 Dec 2021 10:13:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230299AbhLKKN5 (ORCPT ); Sat, 11 Dec 2021 05:13:57 -0500 Received: from mxout03.lancloud.ru ([45.84.86.113]:56150 "EHLO mxout03.lancloud.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229514AbhLKKN4 (ORCPT ); Sat, 11 Dec 2021 05:13:56 -0500 Received: from LanCloud DKIM-Filter: OpenDKIM Filter v2.11.0 mxout03.lancloud.ru 5EB4D20EBC8C Received: from LanCloud Received: from LanCloud Received: from LanCloud Message-ID: <8ec4a971-29ba-77f7-7c48-ad88decea70f@omp.ru> Date: Sat, 11 Dec 2021 13:13:52 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.3.2 Subject: Re: [PATCH v1 1/2] ata: libahci_platform: Get rid of dup message when IRQ can't be retrieved Content-Language: en-US To: Sergey Shtylyov , Andy Shevchenko CC: Damien Le Moal , , , Hans de Goede , Jens Axboe References: <20211209145937.77719-1-andriy.shevchenko@linux.intel.com> <9e6b2e9a-e958-0c14-6570-135607041978@omp.ru> <6c03ffef-b2e0-16ba-35f3-206af2a611d2@gmail.com> <9d688cd8-99e3-0265-06aa-d44597e7686c@omp.ru> <448ce97b-699d-bdab-b4e9-c9439fd81a85@gmail.com> From: Sergey Shtylyov Organization: Open Mobile Platform In-Reply-To: <448ce97b-699d-bdab-b4e9-c9439fd81a85@gmail.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [192.168.11.198] X-ClientProxiedBy: LFEXT02.lancloud.ru (fd00:f066::142) To LFEX1907.lancloud.ru (fd00:f066::207) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10.12.2021 22:35, Sergei Shtylyov wrote: [...] >>>>>>>>>>>> platform_get_irq() will print a message when it fails. >>>>>>>>>>>> No need to repeat this. >>>>>>>>>>>> >>>>>>>>>>>> While at it, drop redundant check for 0 as platform_get_irq() spills >>>>>>>>>>>> out a big WARN() in such case. >>>>>>>>>>> >>>>>>>>>>> The reason you should be able to remove the "if (!irq)" test is that >>>>>>>>>>> platform_get_irq() never returns 0. At least, that is what the function kdoc >>>>>>>>>>> says. But looking at platform_get_irq_optional(), which is called by >>>>>>>>>>> platform_get_irq(), the out label is: >>>>>>>>>>> >>>>>>>>>>> WARN(ret == 0, "0 is an invalid IRQ number\n"); >>>>>>>>>>> return ret; >>>>>>>>>>> >>>>>>>>>>> So 0 will be returned as-is. That is rather weird. That should be fixed to >>>>>>>>>>> return -ENXIO: >>>>>>>>>>> >>>>>>>>>>> if (WARN(ret == 0, "0 is an invalid IRQ number\n")) >>>>>>>>>>> return -ENXIO; >>>>>>>>>>> return ret; >>>>>>>>>> >>>>>>>>>> My unmerged patch (https://marc.info/?l=linux-kernel&m=163623041902285) does this >>>>>>>>>> but returns -EINVAL instead. >>>>>>>>>> >>>>>>>>>>> Otherwise, I do not think that removing the "if (!irq)" hunk is safe. no ? >>>>>>>>>> >>>>>>>>>> Of course it isn't... >>>>>>>>> >>>>>>>>> It's unsubstantiated statement. The vIRQ 0 shouldn't be returned by any of >>>>>>>>> those API calls. >>>>>>>> >>>>>>>> We do _not_ know what needs to be fixed, that's the problem, and that's why the WARN() >>>>>>>> is there... >>>>>>> >>>>>>> So, have you seen this warning (being reported) related to libahci_platform? >>>>>> >>>>>> No (as if you need to really see this while it's obvious from the code review). >>>>>> >>>>>>> If no, what we are discussing about then? The workaround is redundant and >>>>>> >>>>>> I don't know. :-) Your arguments so far seem bogus (sorry! :-))... >>>>> >>>>> It seems you haven't got them at all. The problems of platform_get_irq() et al >>>>> shouldn't be worked around in the callers. >>>> >>>> I have clearly explained to you what I'm working around there. If that wasn't clear >>>> enough, I don't want to continue this talk anymore. Good luck with your patch (not this >>>> one). >>> >>> Good luck with yours, not the one that touches platform_get_irq_optional() though! >> >> Mmh, I'm not touching it any way that would break what your patch was trying to do, >> unless you've re-thopught that. It also shoudn't matter whose patch gets merged 1st >> other than some small adaptation). > > BTW, looking at [1], this comment is wrong: > > + * Return: non-zero IRQ number on success, negative error number on failure. > > It doesn't mention 0 which you return from this function. Also, your commit log is wrong in the description of how to handle the result: << Now: ret = platform_get_irq_optional(...); if (ret != -ENXIO) return ret; // respect deferred probe if (ret > 0) ...we get an IRQ... >> The (ret != -ENXIO) check also succeeds on the (positive) IRQ #s, so the following code becomes unreachable. :-/ > [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ed7027fdf4ec41ed6df6814956dc11860232a9d5 MBR, Sergey