From patchwork Tue Sep 19 08:52:41 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Huacai Chen X-Patchwork-Id: 9958475 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id EFB1B60208 for ; Tue, 19 Sep 2017 08:52:09 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id BC9C12880F for ; Tue, 19 Sep 2017 08:52:09 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B15B1289B7; Tue, 19 Sep 2017 08:52:09 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 515A02880F for ; Tue, 19 Sep 2017 08:52:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751502AbdISIwI (ORCPT ); Tue, 19 Sep 2017 04:52:08 -0400 Received: from smtpbgbr2.qq.com ([54.207.22.56]:51930 "EHLO smtpbgbr2.qq.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751053AbdISIwG (ORCPT ); Tue, 19 Sep 2017 04:52:06 -0400 X-QQ-mid: bizesmtp2t1505811096tk7iw5ck7 Received: from software.domain.org (unknown [222.92.8.142]) by esmtp4.qq.com (ESMTP) with id ; Tue, 19 Sep 2017 16:51:35 +0800 (CST) X-QQ-SSF: 01100000008000F0FNF0B00A0000000 X-QQ-FEAT: yE1moX/8tMbqC9rEGojRSqi7sOp4fuhHm6RTCueHSJrA47I9EdIMVnHN/p59B 6YT8aZfajukMO2cryu2nhayaqsy7Du1BJFkMJ4n8viI99WAx8P7XL5BXsy2tyUEvd+qWIGL WrVgW3KHMXYnPT8LcYTYHlvBtOh9aB5wYh5mIYHmcXzI0ed61D3iFzR79/t5NIO97h8g2Pe +NqFRoKvOo2IIOdfoB+TOzNX8Kta+DQeNHUfsf7VGcZW/M0Q3cOUefS7GbCF8v072fMFMYn 6DnOBmI4t1hKUnF3Jts6FFYvAxBDbvP3vX3TtabLxYJ0RX X-QQ-GoodBg: 0 From: Huacai Chen To: Christoph Hellwig Cc: Marek Szyprowski , Robin Murphy , Andrew Morton , Fuxin Zhang , linux-kernel@vger.kernel.org, "James E . J . Bottomley" , "Martin K . Petersen" , linux-scsi@vger.kernel.org, Huacai Chen , stable@vger.kernel.org Subject: [PATCH V6 3/3] scsi: Align block queue to dma_get_cache_alignment() Date: Tue, 19 Sep 2017 16:52:41 +0800 Message-Id: <1505811161-25246-3-git-send-email-chenhc@lemote.com> X-Mailer: git-send-email 2.7.0 In-Reply-To: <1505811161-25246-1-git-send-email-chenhc@lemote.com> References: <1505811161-25246-1-git-send-email-chenhc@lemote.com> X-QQ-SENDSIZE: 520 Feedback-ID: bizesmtp:lemote.com:qybgforeign:qybgforeign1 X-QQ-Bgrelay: 1 Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP In non-coherent DMA mode, kernel uses cache flushing operations to maintain I/O coherency, so scsi's block queue should be aligned to ARCH_DMA_MINALIGN. Otherwise, it will cause data corruption, at least on MIPS: Step 1, dma_map_single Step 2, cache_invalidate (no writeback) Step 3, dma_from_device Step 4, dma_unmap_single 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 lost. Cc: stable@vger.kernel.org Signed-off-by: Huacai Chen --- drivers/scsi/scsi_lib.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 9cf6a80..19abc2e 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -2132,11 +2132,11 @@ void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q) q->limits.cluster = 0; /* - * set a reasonable default alignment on word boundaries: the - * host and device may alter it using + * set a reasonable default alignment on word/cacheline boundaries: + * the host and device may alter it using * blk_queue_update_dma_alignment() later. */ - blk_queue_dma_alignment(q, 0x03); + blk_queue_dma_alignment(q, max(4, dma_get_cache_alignment(dev)) - 1); } EXPORT_SYMBOL_GPL(__scsi_init_queue);