Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754296AbYGIUAT (ORCPT ); Wed, 9 Jul 2008 16:00:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751412AbYGIUAF (ORCPT ); Wed, 9 Jul 2008 16:00:05 -0400 Received: from accolon.hansenpartnership.com ([76.243.235.52]:42165 "EHLO accolon.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751335AbYGIUAA (ORCPT ); Wed, 9 Jul 2008 16:00:00 -0400 Subject: Re: [PATCH] Mark i2o config broken on 64-bit platforms. From: James Bottomley To: Miquel van Smoorenburg Cc: Alan Cox , David Howells , akpm@linux-foundation.org, alan@redhat.com, Markus.Lidel@shadowconnect.com, vvs@sw.ru, linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org In-Reply-To: <1215631336.18506.15.camel@localhost.localdomain> References: <20080709113547.19235.15424.stgit@warthog.procyon.org.uk> <4561.1215612914@redhat.com> <20080709164929.799e4e05@the-village.bc.nu> <1215630402.18506.10.camel@localhost.localdomain> <1215630817.3444.16.camel@localhost.localdomain> <1215631336.18506.15.camel@localhost.localdomain> Content-Type: text/plain Date: Wed, 09 Jul 2008 14:59:55 -0500 Message-Id: <1215633595.3444.18.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 (2.22.3.1-1.fc9) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1926 Lines: 45 On Wed, 2008-07-09 at 21:22 +0200, Miquel van Smoorenburg wrote: > On Wed, 2008-07-09 at 14:13 -0500, James Bottomley wrote: > > On Wed, 2008-07-09 at 21:06 +0200, Miquel van Smoorenburg wrote: > > > On Wed, 2008-07-09 at 16:49 +0100, Alan Cox wrote: > > > > On Wed, 09 Jul 2008 15:15:14 +0100 > > > > David Howells wrote: > > > > > > > > > Miquel van Smoorenburg wrote: > > > > > Maybe, but have you looked at i2o_cfg_passthru()? Take this, for example: > > > > > > > > > > /* Allocate memory for the transfer */ > > > > > p = kmalloc(sg_size, GFP_KERNEL); > > > > > ... > > > > > //TODO 64bit fix > > > > > sg[i].addr_bus = virt_to_bus(p); > > > > > > > > > > That looks distinctly dodgy. virt_to_bus() returns a 64-bit address, and as > > > > > > > > Agreed - stick | GFP_DMA32 on the end then ;) > > > > > > GFP_DMA32 doesn't work with kmalloc(), you need dma_alloc_coherent() or > > > pci_alloc_consistent() [here, i2o_dma_alloc() ] > > > > Yes it does ... it was specifically designed for it. GFP_DMA32 was > > introduced to allow this type of thing to happen (in the old days most > > drivers were allowed to assume kmalloc would return memory whose > > physical address was < 4GB; GFP_DMA32 allows that to continue while > > allowing kmalloc to stray beyond 4GB physical). > > If you use alloc_pages(), yes. But not for kmalloc(). There are no > general GFP_DMA32 slabs. No ... it's platform specific. Platforms whose ZONE_NORMAL covers only up to 4GB need do nothing. However, x86_64 definitely implements ZONE_DMA32 for precisely this. Several other platforms (like ia64) should but don't. James -- 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/