From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933119AbdKQEaL (ORCPT ); Thu, 16 Nov 2017 23:30:11 -0500 Received: from mail-pg0-f66.google.com ([74.125.83.66]:44636 "EHLO mail-pg0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932695AbdKQEaD (ORCPT ); Thu, 16 Nov 2017 23:30:03 -0500 X-Google-Smtp-Source: AGs4zMaJ8NkLoxsms7P9DG6vRY0lNWU3zoYFybdu4FjRRbi8jqjCZGisR0BrCNcaVrq2Cl0uj7m//w== From: Huacai Chen To: Christoph Hellwig Cc: Marek Szyprowski , Robin Murphy , Andrew Morton , Fuxin Zhang , linux-mips@linux-mips.org, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, Huacai Chen Subject: [PATCH V10 3/4] scsi: Align block queue to dma_get_cache_alignment() Date: Fri, 17 Nov 2017 12:30:05 +0800 Message-Id: <1510893005-325-1-git-send-email-chenhc@lemote.com> X-Mailer: git-send-email 2.7.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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, 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. 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 1cbc497..cc4ac97 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -2148,11 +2148,11 @@ 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); -- 2.7.0