From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751099AbdIKIme (ORCPT ); Mon, 11 Sep 2017 04:42:34 -0400 Received: from smtpbguseast2.qq.com ([54.204.34.130]:46666 "EHLO smtpbguseast2.qq.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751022AbdIKImd (ORCPT ); Mon, 11 Sep 2017 04:42:33 -0400 X-QQ-GoodBg: 0 X-QQ-SSF: 00100000000000F0 X-QQ-FEAT: lObuly5bpiVQp+1tKXTnfWhGMK4USR5LOjgmspIc7zz0W1/o1NPxRV8iYBkTl 8uAYbHdseldKHFrizeyQUzQTmuPpIGXJxy4GE6L5T7eauZ6eUs7xEiFaO3xtOWeDsBH5b7z F1uneaGDuDIe+hPLIg5MmwwPpng9N4h54GM8XtbZ1eCN4rMIZ5rgWhRNaULwlsKqPg9I1tF sBHpMX5aMSKy1iqNZ6aQHn36ZnFje1iF4l+Omm19DJx8pmnXGKxpYhOckl0mWovhDvb2cd8 LAywMSkthSmh2l X-QQ-BUSINESS-ORIGIN: 2 X-Originating-IP: 222.92.124.153 X-QQ-STYLE: X-QQ-mid: bizmailfree34t1505119311t2183 From: "=?utf-8?B?6ZmI5Y2O5omN?=" To: "=?utf-8?B?Q2hyaXN0b3BoIEhlbGx3aWc=?=" Cc: "=?utf-8?B?SmFtZXMgRSAuIEogLiBCb3R0b21sZXk=?=" , "=?utf-8?B?TWFydGluIEsgLiBQZXRlcnNlbg==?=" , "=?utf-8?B?RnV4aW4gWmhhbmc=?=" , "=?utf-8?B?bGludXgtc2NzaQ==?=" , "=?utf-8?B?bGludXgta2VybmVs?=" , "=?utf-8?B?c3RhYmxl?=" Subject: Re: [PATCH 2/2] scsi: Align queue to ARCH_DMA_MINALIGN innon-coherent DMA mode Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Date: Mon, 11 Sep 2017 16:41:51 +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: <1504774131-11691-1-git-send-email-chenhc@lemote.com> <20170911073906.GA7074@infradead.org> In-Reply-To: <20170911073906.GA7074@infradead.org> X-QQ-ReplyHash: 1105147107 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 v8B8gec9007765 Hi, Christoph I think we cannot modify dma_get_cache_alignment(), because existing callers may want to unconditionally return ARCH_DMA_MINALIGN. Huacai ------------------ Original ------------------ From: "Christoph Hellwig"; Date: Mon, Sep 11, 2017 03:39 PM To: "Huacai Chen"; Cc: "James E . J . Bottomley"; "Martin K . Petersen"; "Fuxin Zhang"; "linux-scsi"; "linux-kernel"; "stable"; Subject: Re: [PATCH 2/2] scsi: Align queue to ARCH_DMA_MINALIGN innon-coherent DMA mode > + if (plat_device_is_coherent(dev)) We can't just call platform device code. We'll need a proper DMA API call for this. > + blk_queue_dma_alignment(q, 0x04 - 1); > + else > + blk_queue_dma_alignment(q, dma_get_cache_alignment() - 1); Which we already have with dma_get_cache_alignment, except that it doesn't take a struct device pointer and doesn't call into dma_map ops. So please add a struct device argument to dma_get_cache_alignment, and let it call into dma_map_ops where needed. With that you can replace the above with: blk_queue_dma_alignment(q, max(0x04U, dma_get_cache_alignment(dev)) - 1);