Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753261AbaGBLCv (ORCPT ); Wed, 2 Jul 2014 07:02:51 -0400 Received: from mail.windriver.com ([147.11.1.11]:44335 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753073AbaGBLCu (ORCPT ); Wed, 2 Jul 2014 07:02:50 -0400 Message-ID: <53B3E6B4.2040907@windriver.com> Date: Wed, 2 Jul 2014 19:02:12 +0800 From: "Yang,Wei" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.0 MIME-Version: 1.0 To: Russell King - ARM Linux CC: , , Subject: Re: [PATCH v1] ARM:sa1100: Remove a redundant spin lock References: <1404200488-7809-1-git-send-email-Wei.Yang@windriver.com> <53B3CEAC.9080609@windriver.com> <20140702101925.GE32514@n2100.arm.linux.org.uk> In-Reply-To: <20140702101925.GE32514@n2100.arm.linux.org.uk> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [128.224.162.170] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/02/2014 06:19 PM, Russell King - ARM Linux wrote: > On Wed, Jul 02, 2014 at 05:19:40PM +0800, Yang,Wei wrote: >> Hi Guys, >> >> What about this patch? > The only concern on the face of it is that it removes mutual exclusion > from the pci config write path, where a read-modifiy-write operation is > performed. > > However, the PCI code already gives that guarantee (drivers/pci/access.c) > so this should be safe. > > As this is fairly old code, it would be useful to know what the motivation > is behind this change. Is it purely clean up, or is it something that > you've tested, or is this a change that you require for something else? > > Thanks. > Hmm, I fixed a bug of pci config read/write of an ARM board, but unfortunately, so far ML does not support it. So I cannot send the fix, but I grepped the pci source code of ARM architecure, I found that the pci code of a few boards always define a static spin lock to excluse the pci config read/write path. I just intended to clean up them. If you agree the change, I want to send v2 to also remove this mutual exclusion for something else board which also used the mutual exclusion. Thanks Wei -- 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/