From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [PATCH 2.6.24-rc1] sata_promise: fix endianess bug in ASIC PRD bug workaround Date: Sat, 03 Nov 2007 08:48:33 -0400 Message-ID: <472C6E21.6020303@garzik.org> References: <200710311221.l9VCLTiG008243@harpo.it.uu.se> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from srv5.dvmed.net ([207.36.208.214]:35163 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755408AbXKCMsf (ORCPT ); Sat, 3 Nov 2007 08:48:35 -0400 In-Reply-To: <200710311221.l9VCLTiG008243@harpo.it.uu.se> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Mikael Pettersson Cc: linux-ide@vger.kernel.org, Alexander Sabourenkov Mikael Pettersson wrote: > The original workaround for the Promise ASIC PRD bug > contained an endianess bug which I failed to detect: > the adjustment of the last PRD entry's length field > applied host arithmetic to little-endian data, which > is incorrect on big-endian machines. > > We have the length available in host-endian format, so > do the adjustment on host-endian data and then convert > and store it in the PRD entry's little-endian data field. > > Thanks to an anonymous reviewer for detecting this bug. > > Signed-off-by: Mikael Pettersson > --- > Jeff: please include this fix in any backport(s) of the > ASIC PRD bug workaround. > > drivers/ata/sata_promise.c | 2 +- > 1 files changed, 1 insertion(+), 1 deletion(-) > > diff -rupN linux-2.6.24-rc1/drivers/ata/sata_promise.c linux-2.6.24-rc1.sata_promise-endianess-fix/drivers/ata/sata_promise.c > --- linux-2.6.24-rc1/drivers/ata/sata_promise.c 2007-10-31 11:47:13.000000000 +0100 > +++ linux-2.6.24-rc1.sata_promise-endianess-fix/drivers/ata/sata_promise.c 2007-10-31 11:47:25.000000000 +0100 > @@ -585,7 +585,7 @@ static void pdc_fill_sg(struct ata_queue > VPRINTK("Splitting last PRD.\n"); > > addr = le32_to_cpu(ap->prd[idx - 1].addr); > - ap->prd[idx - 1].flags_len -= cpu_to_le32(SG_COUNT_ASIC_BUG); > + ap->prd[idx - 1].flags_len = cpu_to_le32(len - SG_COUNT_ASIC_BUG); > VPRINTK("PRD[%u] = (0x%X, 0x%X)\n", idx - 1, addr, SG_COUNT_ASIC_BUG); > > addr = addr + len - SG_COUNT_ASIC_BUG; > - applied