From: Tejun Heo Date: Thu, 20 Jan 2011 12:59:06 +0000 (+0100) Subject: libata: set queue DMA alignment to sector size for ATAPI too X-Git-Tag: v2.6.33.13~5 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=c64507d3285593809167ad35fa738660d197d851;p=karo-tx-linux.git libata: set queue DMA alignment to sector size for ATAPI too 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: Jonathan Liu Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c index 551662456c59..89c0b0645f7f 100644 --- a/drivers/ata/libata-scsi.c +++ b/drivers/ata/libata-scsi.c @@ -1099,13 +1099,13 @@ static int ata_scsi_dev_config(struct scsi_device *sdev, /* configure max sectors */ blk_queue_max_sectors(sdev->request_queue, dev->max_sectors); + sdev->sector_size = ATA_SECT_SIZE; + if (dev->class == ATA_DEV_ATAPI) { 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); + /* set DMA padding */ blk_queue_update_dma_pad(sdev->request_queue, ATA_DMA_PAD_SZ - 1); @@ -1119,12 +1119,24 @@ 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, + sdev->sector_size - 1); + if (dev->flags & ATA_DFLAG_AN) set_bit(SDEV_EVT_MEDIA_CHANGE, sdev->supported_events);