From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030212Ab2CMAZ5 (ORCPT ); Mon, 12 Mar 2012 20:25:57 -0400 Received: from mail.windriver.com ([147.11.1.11]:49195 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965257Ab2CMAZy (ORCPT ); Mon, 12 Mar 2012 20:25:54 -0400 From: Paul Gortmaker To: stable@kernel.org, linux-kernel@vger.kernel.org Cc: stable-review@kernel.org, Tejun Heo , Tejun Heo , Jeff Garzik , Paul Gortmaker Subject: [34-longterm 166/196] libata: set queue DMA alignment to sector size for ATAPI too Date: Mon, 12 Mar 2012 20:21:19 -0400 Message-Id: <1331598109-31424-121-git-send-email-paul.gortmaker@windriver.com> X-Mailer: git-send-email 1.7.9.3 In-Reply-To: <1331598109-31424-1-git-send-email-paul.gortmaker@windriver.com> References: <1331597724-31358-1-git-send-email-paul.gortmaker@windriver.com> <1331598109-31424-1-git-send-email-paul.gortmaker@windriver.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Tejun Heo ------------------- This is a commit scheduled for the next v2.6.34 longterm release. If you see a problem with using this for longterm, please comment. ------------------- commit 729a6a300e628a48cf12bac93a964a535e83cd1d upstream. ata_pio_sectors() expects buffer for each sector to be contained in a single page; otherwise, it ends up overrunning the first page. This is achieved by setting queue DMA alignment. If sector_size is smaller than PAGE_SIZE and all buffers are sector_size aligned, buffer for each sector is always contained in a single page. This wasn't applied to ATAPI devices but IDENTIFY_PACKET is executed as ATA_PROT_PIO and thus uses ata_pio_sectors(). Newer versions of udev issue IDENTIFY_PACKET with unaligned buffer triggering the problem and causing oops. This patch fixes the problem by setting sdev->sector_size to ATA_SECT_SIZE on ATATPI devices and always setting DMA alignment to sector_size. While at it, add a warning for the unlikely but still possible scenario where sector_size is larger than PAGE_SIZE, in which case the alignment wouldn't be enough. Signed-off-by: Tejun Heo Reported-by: John Stanley Tested-by: John Stanley Signed-off-by: Jeff Garzik Signed-off-by: Paul Gortmaker --- drivers/ata/libata-scsi.c | 24 ++++++++++++++++++------ 1 file changed, 18 insertions(+), 6 deletions(-) diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c index 1d266e2..0dfa468 100644 --- a/drivers/ata/libata-scsi.c +++ b/drivers/ata/libata-scsi.c @@ -1104,9 +1104,9 @@ static int ata_scsi_dev_config(struct scsi_device *sdev, struct request_queue *q = sdev->request_queue; void *buf; - /* set the min alignment and padding */ - blk_queue_update_dma_alignment(sdev->request_queue, - ATA_DMA_PAD_SZ - 1); + sdev->sector_size = ATA_SECT_SIZE; + + /* set DMA padding */ blk_queue_update_dma_pad(sdev->request_queue, ATA_DMA_PAD_SZ - 1); @@ -1120,12 +1120,24 @@ static int ata_scsi_dev_config(struct scsi_device *sdev, blk_queue_dma_drain(q, atapi_drain_needed, buf, ATAPI_MAX_DRAIN); } else { - /* ATA devices must be sector aligned */ - blk_queue_update_dma_alignment(sdev->request_queue, - ATA_SECT_SIZE - 1); sdev->manage_start_stop = 1; } + /* + * ata_pio_sectors() expects buffer for each sector to not cross + * page boundary. Enforce it by requiring buffers to be sector + * aligned, which works iff sector_size is not larger than + * PAGE_SIZE. ATAPI devices also need the alignment as + * IDENTIFY_PACKET is executed as ATA_PROT_PIO. + */ + if (sdev->sector_size > PAGE_SIZE) + ata_dev_printk(dev, KERN_WARNING, + "sector_size=%u > PAGE_SIZE, PIO may malfunction\n", + sdev->sector_size); + + blk_queue_update_dma_alignment(sdev->request_queue, + ATA_SECT_SIZE - 1); + if (dev->flags & ATA_DFLAG_AN) set_bit(SDEV_EVT_MEDIA_CHANGE, sdev->supported_events); -- 1.7.9.3