From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ivan Kokshaysky Subject: Re: 2.6.22-rc6 bad page error Date: Thu, 12 Jul 2007 13:46:06 +0400 Message-ID: <20070712134606.A10012@jurassic.park.msu.ru> References: <20070709185324.387ACDBA1@gherkin.frus.com> <20070711170245.A1148@jurassic.park.msu.ru> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: ; from hugh@veritas.com on Wed, Jul 11, 2007 at 06:07:59PM +0100 Sender: linux-alpha-owner@vger.kernel.org List-Id: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Hugh Dickins Cc: Bob Tracy , Michal Piotrowski , linux-kernel@vger.kernel.org, linux-alpha@vger.kernel.org, Andrew Morton On Wed, Jul 11, 2007 at 06:07:59PM +0100, Hugh Dickins wrote: > > + gfp &= ~GFP_DMA; > > The canonical form for this masking, even on arches without HIGHMEM, > appears to be: > gfp &= ~(__GFP_DMA | __GFP_HIGHMEM); > But I guess that won't make any actual difference. As far as I can see, none of 64-bit architectures masks the HIGHMEM (or any other) bits. It's just not obvious because most of their "alloc_coherent" routines are hidden in iommu_ops or something like that. > > + return __pci_alloc_consistent(dev, size, dma, GFP_ATOMIC); > > I was going to ask you why that needs to be GFP_ATOMIC on Alpha. > But find you're following the example of asm-generic and others. > So really should be asking Sparc how it gets away with GFP_KERNEL. According to DMA-mapping.txt GFP_ATOMIC is mandatory for pci_alloc_consistent() since it can be called from interrupt context. So sparc code is probably incorrect... Ivan.