From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756035Ab1EPU4D (ORCPT ); Mon, 16 May 2011 16:56:03 -0400 Received: from rcsinet10.oracle.com ([148.87.113.121]:48285 "EHLO rcsinet10.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755563Ab1EPU4B (ORCPT ); Mon, 16 May 2011 16:56:01 -0400 Message-ID: <4DD18F4A.5030208@kernel.org> Date: Mon, 16 May 2011 13:55:38 -0700 From: Yinghai Lu User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.17) Gecko/20110414 SUSE/3.1.10 Thunderbird/3.1.10 MIME-Version: 1.0 To: Ram Pai CC: Jesse Barnes , Linus Torvalds , "linux-kernel@vger.kernel.org" , "linux-pci@vger.kernel.org" , Andrew Morton , Bjorn Helgaas Subject: Re: [PATCH -v2] pci: Check bridge resources after resource allocation. References: <20110509142014.617e3100@jbarnes-desktop> <4DC9E415.5010402@kernel.org> <20110512180638.GA5012@ram-laptop> <20110512182229.GQ8195@ram-laptop> <20110512113726.123fd85b@jbarnes-desktop> <20110512123412.64e9b4cc@jbarnes-desktop> <4DCDD589.8010309@kernel.org> <20110516075926.GW8195@ram-laptop> In-Reply-To: <20110516075926.GW8195@ram-laptop> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Source-IP: acsinet21.oracle.com [141.146.126.237] X-Auth-Type: Internal IP X-CT-RefId: str=0001.0A090209.4DD18F53.0141,ss=1,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/16/2011 12:59 AM, Ram Pai wrote: > On Fri, May 13, 2011 at 06:06:17PM -0700, Yinghai Lu wrote: >> On 05/12/2011 12:34 PM, Jesse Barnes wrote: >>> On Thu, 12 May 2011 12:18:43 -0700 >>> Linus Torvalds wrote: >>> >>>> On Thu, May 12, 2011 at 11:37 AM, Jesse Barnes wrote: >>>>> >>>>> Linus, I don't have anything else queued up, so you may as well take >>>>> this one directly if you want it in 2.6.39. It's a regression fix, but >>>>> resource changes always make me nervous. Alternately, I could put it >>>>> into 2.6.40 instead, the backport to 2.6.39.x if it survives until >>>>> 2.6.40-rc2 or so... >>>> >>>> Considering the trouble resource allocation always ends up being, I'd >>>> almost prefer that "mark it for stable and put it in the 2.6.40 >>>> queue". >>>> >>>> Afaik this problem hasn't actually hit any "normal" users, has it? So ... >>> >>> Sounds good, thanks. Yeah I don't think it's hit anyone but Yinghai >>> (at least I don't know of any other reports). >>> >> >> please check this one, it should be safe for 2.6.39 ? > >> size0 = calculate_iosize(size, min_size, size1, >> resource_size(b_res), 4096); >> - size1 = !add_size? size0: >> + size1 = (!add_head || (add_head && !add_size)) ? size0 : >> calculate_iosize(size, min_size+add_size, size1, >> resource_size(b_res), 4096); > > This solves the problem you encountered. > > But, I think, it still does not fix the following scenario: > > adjust_resource() failing to allocate additional resource to a hotplug bridge > that has no children. In this case ->flags of that 'struct resource' > continues to be set even when no resource is allocated to that hot-plug bridge. > that case: requested_size will be 0, but add_size will not be zero. res->flags is not cleared in pbus_size_xx, so it will be put into head. so it will go through first path. ... if (!resource_size(res) && add_size) { res->end = res->start + add_size - 1; if(pci_assign_resource(list->dev, idx)) reset_resource(res); } else if (add_size) { adjust_resource(res, res->start, resource_size(res) + add_size); } and if it fails to get assign, the flags will get clear in reset_resource. so it should be ok. and testing in one my setup show those flags get clear correctly and does not emit any warning. Thanks Yinghai