Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751537AbWHXNpR (ORCPT ); Thu, 24 Aug 2006 09:45:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751534AbWHXNpQ (ORCPT ); Thu, 24 Aug 2006 09:45:16 -0400 Received: from elvis.mu.org ([192.203.228.196]:24002 "EHLO elvis.mu.org") by vger.kernel.org with ESMTP id S1751537AbWHXNpP (ORCPT ); Thu, 24 Aug 2006 09:45:15 -0400 Message-ID: <44EDAD41.9080204@FreeBSD.org> Date: Thu, 24 Aug 2006 15:44:33 +0200 From: Suleiman Souhlal User-Agent: Mozilla Thunderbird 1.0.7 (X11/20051204) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Arjan van de Ven CC: Andi Kleen , Edward Falk , linux-kernel@vger.kernel.org Subject: Re: [PATCH] Fix x86_64 _spin_lock_irqsave() References: <44ED157D.6050607@google.com> <44ED87AC.8070106@FreeBSD.org> <200608241332.40139.ak@suse.de> <44ED9CB4.7070302@FreeBSD.org> <1156425718.3014.64.camel@laptopd505.fenrus.org> In-Reply-To: <1156425718.3014.64.camel@laptopd505.fenrus.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1579 Lines: 51 Arjan van de Ven wrote: > On Thu, 2006-08-24 at 14:33 +0200, Suleiman Souhlal wrote: > >>Andi Kleen wrote: >> >>>On Thursday 24 August 2006 13:04, Suleiman Souhlal wrote: >>> >>> >>>>Andi Kleen wrote: >>>> >>>> >>>>>Edward Falk writes: >>>>> >>>>> >>>>> >>>>> >>>>>>Add spin_lock_string_flags and _raw_spin_lock_flags() to >>>>>>asm-x86_64/spinlock.h so that _spin_lock_irqsave() has the same >>>>>>semantics on x86_64 as it does on i386 and does *not* have interrupts >>>>>>disabled while it is waiting for the lock. >>>>> >>>>> >>>>>Did it fix anything for you? >>>> >>>>I think this was to work around the fact that some buggy drivers try to >>>>grab spinlocks without disabling interrupts when they should, which >>>>would cause deadlocks when trying to rendez-vous every cpu via IPIs. >>> >>> >>>That doesn't help them at all because they could then deadlock later. >> >>If the driver uses spin_lock() when it knows that the hardware won't >>generate the interrupt that would need to be masked, and >>spin_lock_irqsave() elsewhere, there shouldn't be any deadlocks unless >>IPIs are involved. > > > this still is bad practice and lockdep will also scream about it Great. > Can you point at ANY place that does this? From a quick inspection, drivers/net/forcedeth.c appears to do this. -- Suleiman - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/