From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758770AbdJRBHP (ORCPT ); Tue, 17 Oct 2017 21:07:15 -0400 Received: from smtpproxy19.qq.com ([184.105.206.84]:47184 "EHLO smtpproxy19.qq.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755214AbdJRBHN (ORCPT ); Tue, 17 Oct 2017 21:07:13 -0400 X-QQ-GoodBg: 0 X-QQ-SSF: 00100000000000F0 X-QQ-FEAT: jPIikJM0fyOyzOikRvL8aQ3w9gD6dcy3eGTZlhhGyOE8gm6ZPfKfI8dVZVPPD apJxNTS9EDN6Jx2VV2nZZ7ftR8FaGJrJixAxrCDWgMHoIiKTO4Kd1X/gGHoV4W7doR5rJQL g/DgeiuACFeFfG3x+1ri8tZUItU6gDH3CNo7qu+dQg7HY921GGbPg6mY0st2O0HY3k5ZaZB GSDfalu9CHBPxPNY1PducGuXf1gmr0txJQ716Y1B72PxYHOsAiM6mPUjC2k3O7jpfD68aeY W/xJ5E4MRL/ODtxlPw2kXFka4LxSCB9CGapQ== X-QQ-BUSINESS-ORIGIN: 2 X-Originating-IP: 222.92.124.153 X-QQ-STYLE: X-QQ-mid: bizmailfree34t1508288818t1377 From: "=?utf-8?B?6ZmI5Y2O5omN?=" To: "=?utf-8?B?U2VyZ2VpIFNodHlseW92?=" , "=?utf-8?B?Q2hyaXN0b3BoIEhlbGx3aWc=?=" Cc: "=?utf-8?B?TWFyZWsgU3p5cHJvd3NraQ==?=" , "=?utf-8?B?Um9iaW4gTXVycGh5?=" , "=?utf-8?B?QW5kcmV3IE1vcnRvbg==?=" , "=?utf-8?B?RnV4aW4gWmhhbmc=?=" , "=?utf-8?B?bGludXgta2VybmVs?=" , "=?utf-8?B?UmFsZiBCYWVjaGxl?=" , "=?utf-8?B?SmFtZXMgSG9nYW4=?=" , "=?utf-8?B?bGludXgtbWlwcw==?=" , "=?utf-8?B?SmFtZXMgRSAuIEogLiBCb3R0b21sZXk=?=" , "=?utf-8?B?TWFydGluIEsgLiBQZXRlcnNlbg==?=" , "=?utf-8?B?bGludXgtc2NzaQ==?=" , "=?utf-8?B?VGVqdW4gSGVv?=" , "=?utf-8?B?bGludXgtaWRl?=" , "=?utf-8?B?c3RhYmxl?=" Subject: Re: [PATCH V8 5/5] libata: Align DMA buffer todma_get_cache_alignment() Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Date: Wed, 18 Oct 2017 09:06:58 +0800 X-Priority: 3 Message-ID: X-QQ-MIME: TCMime 1.0 by Tencent X-Mailer: QQMail 2.x X-QQ-Mailer: QQMail 2.x References: <1508227542-13165-1-git-send-email-chenhc@lemote.com> <1508227542-13165-5-git-send-email-chenhc@lemote.com> <94f55c1e-7553-0fc8-124e-ac6df5ac10ce@cogentembedded.com> In-Reply-To: <94f55c1e-7553-0fc8-124e-ac6df5ac10ce@cogentembedded.com> X-QQ-ReplyHash: 499386347 X-QQ-SENDSIZE: 520 Feedback-ID: bizmailfree:lemote.com:qybgforeign:qybgforeign1 X-QQ-Bgrelay: 1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by nfs id v9I17Kfr005404 Hi, Sergei, Without this patch, in non-coherent mode, ata_do_set_mode() return with "no PIO support", and disk detection fails. Huacai ------------------ Original ------------------ From: "Sergei Shtylyov"; Date: Tue, Oct 17, 2017 05:43 PM To: "Huacai Chen"; "Christoph Hellwig"; Cc: "Marek Szyprowski"; "Robin Murphy"; "Andrew Morton"; "Fuxin Zhang"; "linux-kernel"; "Ralf Baechle"; "James Hogan"; "linux-mips"; "James E . J . Bottomley"; "Martin K . Petersen"; "linux-scsi"; "Tejun Heo"; "linux-ide"; "stable"; Subject: Re: [PATCH V8 5/5] libata: Align DMA buffer todma_get_cache_alignment() On 10/17/2017 11:05 AM, Huacai Chen wrote: > In non-coherent DMA mode, kernel uses cache flushing operations to > maintain I/O coherency, so in ata_do_dev_read_id() the DMA buffer > should be aligned to ARCH_DMA_MINALIGN. Otherwise, If a DMA buffer > and a kernel structure share a same cache line, and if the kernel > structure has dirty data, cache_invalidate (no writeback) will cause > data corruption. > > Cc: stable@vger.kernel.org > Signed-off-by: Huacai Chen > --- > drivers/ata/libata-core.c | 15 +++++++++++++-- > 1 file changed, 13 insertions(+), 2 deletions(-) > > diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c > index ee4c1ec..e134955 100644 > --- a/drivers/ata/libata-core.c > +++ b/drivers/ata/libata-core.c > @@ -1833,8 +1833,19 @@ static u32 ata_pio_mask_no_iordy(const struct ata_device *adev) > unsigned int ata_do_dev_read_id(struct ata_device *dev, > struct ata_taskfile *tf, u16 *id) > { > - return ata_exec_internal(dev, tf, NULL, DMA_FROM_DEVICE, > - id, sizeof(id[0]) * ATA_ID_WORDS, 0); > + u16 *devid; > + int res, size = sizeof(u16) * ATA_ID_WORDS; > + > + if (IS_ALIGNED((unsigned long)id, dma_get_cache_alignment(&dev->tdev))) > + res = ata_exec_internal(dev, tf, NULL, DMA_FROM_DEVICE, id, size, 0); > + else { > + devid = kmalloc(size, GFP_KERNEL); > + res = ata_exec_internal(dev, tf, NULL, DMA_FROM_DEVICE, devid, size, 0); > + memcpy(id, devid, size); > + kfree(devid); > + } > + > + return res; This function is called only for the PIO mode commands, so I doubt this is necessary... MBR, Sergei