From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julien Grall Subject: Re: [PATCH for-4.5 6/8] xen/arm: IRQ: Add lock contrainst for gic_irq_{startup, shutdown} Date: Fri, 21 Feb 2014 13:19:36 +0000 Message-ID: <53075268.9090806@linaro.org> References: <1390581822-32624-1-git-send-email-julien.grall@linaro.org> <1390581822-32624-7-git-send-email-julien.grall@linaro.org> <1392810675.29739.15.camel@kazak.uk.xensource.com> <5304C13C.5060505@linaro.org> <1392820736.29739.86.camel@kazak.uk.xensource.com> <5304C4E1.2070901@linaro.org> <5304D6BC020000780011DC4F@nat28.tlf.novell.com> <53066A1F.8020203@linaro.org> <53072299020000780011E259@nat28.tlf.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta5.messagelabs.com ([195.245.231.135]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1WGq10-0006ZS-0P for xen-devel@lists.xenproject.org; Fri, 21 Feb 2014 13:19:42 +0000 Received: by mail-ee0-f45.google.com with SMTP id e53so48629eek.4 for ; Fri, 21 Feb 2014 05:19:38 -0800 (PST) In-Reply-To: <53072299020000780011E259@nat28.tlf.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Jan Beulich Cc: "Keir (Xen.org)" , Ian Campbell , patches@linaro.org, tim@xen.org, stefano.stabellini@citrix.com, xen-devel@lists.xenproject.org List-Id: xen-devel@lists.xenproject.org On 02/21/2014 08:55 AM, Jan Beulich wrote: >>>> On 20.02.14 at 21:48, Julien Grall wrote: >> Before the clean up there was 8 distinct startup routines for x86. No >> there is only 2: >> - drivers/passthrough/amd/iommu_init.c: iommu_maskable_msi_startup >> - arch/x86/ioapic.c: startup_edge_ioapic_irq >> >> For a latter one, I'm a bit surprised that the function can return 1, >> but the result is never used. > > Which means consumption of the return value was intended, but > never implemented (or lost _very_ long ago). Looking at the Linux > code, the intention apparently would be for the non-zero return > value to propagate into IRQ_PENDING in one very special case we > didn't ever support (auto-probing). Re-sending of an already > pending interrupt is being handled differently there anyway. So if > needed something like the setting of IRQ_PENDING at some point, > I guess we could as well have the startup routine do this itself. I.e. > I think converting the return value to void is still fine, as long as > you leave some commentary in > arch/x86/ioapic.c:startup_edge_ioapic_irq(). I will send the patch to change startup prototype separately later. -- Julien Grall