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=-1.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,RDNS_NONE,SPF_HELO_PASS,SPF_NONE autolearn=no autolearn_force=no version=3.4.0 Received: from elvis.franken.de ([193.175.24.41]:34571 "EHLO elvis.franken.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729704AbgCKQDj (ORCPT ); Wed, 11 Mar 2020 12:03:39 -0400 Date: Wed, 11 Mar 2020 17:03:07 +0100 From: Thomas Bogendoerfer To: afzal mohammed Cc: Nathan Chancellor , linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Ralf Baechle , Paul Burton , Florian Fainelli , bcm-kernel-feedback-list@broadcom.com, "Maciej W. Rozycki" , Jiaxun Yang , Keguang Zhang , Huacai Chen , John Crispin Subject: Re: [PATCH v4] MIPS: Replace setup_irq() by request_irq() Message-ID: <20200311160307.GA15464@alpha.franken.de> References: <20200304203144.GA4323@alpha.franken.de> <20200305115759.3186-1-afzal.mohd.ma@gmail.com> <20200311053126.GA48442@ubuntu-m2-xlarge-x86> <20200311090308.GA5060@afzalpc> <20200311104217.GA10615@alpha.franken.de> <20200311131210.GA5115@afzalpc> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200311131210.GA5115@afzalpc> Sender: linux-kernel-owner@vger.kernel.org List-ID: On Wed, Mar 11, 2020 at 06:42:10PM +0530, afzal mohammed wrote: > Hi Thomas, > > On Wed, Mar 11, 2020 at 11:42:17AM +0100, Thomas Bogendoerfer wrote: > > On Wed, Mar 11, 2020 at 02:33:08PM +0530, afzal mohammed wrote: > > > > diff --git a/arch/mips/kernel/cevt-r4k.c b/arch/mips/kernel/cevt-r4k.c > > > > int r4k_clockevent_init(void) > > > { > > > - unsigned long flags = IRQF_PERCPU | IRQF_TIMER | IRQF_SHARED; > > > + unsigned long flags = IRQF_PERCPU | IRQF_TIMER; > > > I don't see why this should help. In my tree only sgi-ip30 removes > > IRQF_SHARED from flags, but then it uses setup_percpu_irq(). > > What do I miss ? > > You did not miss anything. Though it works, i took a wrong route > following the tags & arrived at that solution in a hurry. > (struct irqaction used in sgi-ip30 was used here earlier w/ setup_irq). > > The problem is sanity checks in request_irq() [ rather in > request_thread_iq() ] > > > if (((irqflags & IRQF_SHARED) && !dev_id) || > (!(irqflags & IRQF_SHARED) && (irqflags & IRQF_COND_SUSPEND)) || > ((irqflags & IRQF_NO_SUSPEND) && (irqflags & IRQF_COND_SUSPEND))) > return -EINVAL; > > If IRQF_SHARED is passed, it exepcts a non-NULL dev_id, here it is > NULL, setup_irq() doesn't have any check like that. so request_irq() is not a 1:1 replacement for our current setup_irq(). Or put it the another way our setup_irq() might be buggy, when used for shared interrupts. > So i think proper solution is to add a non NULL dev_id, as removing > IRQF_SHARED might affect some platforms that might be using that > interrupt line shared. > > Patch with non-NULL dev_id below, it works w/ Nathan's test case. I'm not sure, I like the adding of string pointers as dev_id arguments in your patch. How can we make sure they are unique enough for the use case ? I guess using handler as dev_id does a better job here. And before doing that, lets clean up some of the IRQF_SHARED usage first. All sni IRQF_SHARED can go away, the interrupt lines are exclusive there. loongson2ef/lemote-2f/irq.c: looks like the only user of LOONGSON_NORTH_BRIDGE_IRQ, so IRQF_SHARED could go as well. Could someone confirm that ? All other need to stay, IMHO. And v4 is already in mips-next, so I need an incremental patch please. Thomas. -- Crap can work. Given enough thrust pigs will fly, but it's not necessarily a good idea. [ RFC1925, 2.3 ]