Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757828Ab3HBHej (ORCPT ); Fri, 2 Aug 2013 03:34:39 -0400 Received: from mail2-relais-roc.national.inria.fr ([192.134.164.83]:26880 "EHLO mail2-relais-roc.national.inria.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755016Ab3HBHei (ORCPT ); Fri, 2 Aug 2013 03:34:38 -0400 X-IronPort-AV: E=Sophos;i="4.89,799,1367964000"; d="scan'208";a="28261390" Message-ID: <51FB610C.2090201@inria.fr> Date: Fri, 02 Aug 2013 09:34:36 +0200 From: Brice Goglin User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130630 Icedove/17.0.7 MIME-Version: 1.0 To: "Jiang, Dave" CC: "Mason, Jon" , Dan Williams , "Koul, Vinod" , LKML Subject: Re: ioatdma: add ioat_raid_enabled module parameter References: <51F98A3F.3000102@inria.fr> <1375308847.6448.6.camel@djiang5-linux2.ch.intel.com> <20130801171144.GB13747@jonmason-lab> <1375377359.40527.2.camel@djiang5-linux2.ch.intel.com> In-Reply-To: <1375377359.40527.2.camel@djiang5-linux2.ch.intel.com> X-Enigmail-Version: 1.5.1 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3094 Lines: 86 Le 01/08/2013 19:15, Jiang, Dave a écrit : > On Thu, 2013-08-01 at 10:11 -0700, Jon Mason wrote: >> On Wed, Jul 31, 2013 at 03:14:07PM -0700, Jiang, Dave wrote: >>> I'm ok with enabling this for people that just want to use DMA and not >>> RAID. >> I might be crazy, but I'd be in favor of disabling the RAID offload by >> default on non-Atom platforms. >> > I suppose. Technically it is disabled starting with 3.10 because of the > channel switch issue. I'm ok with this disabled by default for the 3.2 > platforms that has broken pq-val. > Here's a patch that may do what you guys are saying. Brice ioatdma: disable RAID by default when buggy and add module param Commit f26df1a1 added a 64-byte alignment requirement for legacy operations to work around a silicon errata when mixing legacy and RAID descriptors. RAID offload is now disabled by default on buggy 3.2 platforms. Passing ioat_raid_enabled=1 force-enables it on all platforms (previous behavior). Passing ioat_raid_enabled=0 force-disables it everywhere. When RAID offload is disabled, legacy operations (memcpy, etc.) can work again without alignment restrictions. Signed-off-by: Brice Goglin --- drivers/dma/ioat/dma_v3.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) Index: b/drivers/dma/ioat/dma_v3.c =================================================================== --- a/drivers/dma/ioat/dma_v3.c 2013-07-31 23:06:24.163810000 +0200 +++ b/drivers/dma/ioat/dma_v3.c 2013-08-02 09:28:51.817037742 +0200 @@ -67,6 +67,11 @@ #include "dma.h" #include "dma_v2.h" +static int ioat_raid_enabled = -1; +module_param(ioat_raid_enabled, int, 0444); +MODULE_PARM_DESC(ioat_raid_enabled, + "control support of RAID offload (-1=enabled unless broken [default], 0=disabled, 1=enabled)"); + /* ioat hardware assumes at least two sources for raid operations */ #define src_cnt_to_sw(x) ((x) + 2) #define src_cnt_to_hw(x) ((x) - 2) @@ -1775,7 +1780,7 @@ int ioat3_dma_probe(struct ioatdma_devic dma->device_alloc_chan_resources = ioat2_alloc_chan_resources; dma->device_free_chan_resources = ioat2_free_chan_resources; - if (is_xeon_cb32(pdev)) + if (ioat_raid_enabled == 1 && is_xeon_cb32(pdev)) dma->copy_align = 6; dma_cap_set(DMA_INTERRUPT, dma->cap_mask); @@ -1783,7 +1788,14 @@ int ioat3_dma_probe(struct ioatdma_devic device->cap = readl(device->reg_base + IOAT_DMA_CAP_OFFSET); - if (is_bwd_noraid(pdev)) + /* disable RAID if: + * force-disabled by module param, + * or not force-enabled on buggy 3.2 platforms, + * or not actually supported. + */ + if (ioat_raid_enabled == 0 + || (ioat_raid_enabled != 1 && is_xeon_cb32(pdev)) + || is_bwd_noraid(pdev)) device->cap &= ~(IOAT_CAP_XOR | IOAT_CAP_PQ | IOAT_CAP_RAID16SS); /* dca is incompatible with raid operations */ -- 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/