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libata: set queue DMA alignment to sector size for ATAPI too

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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 <tj@kernel.org>
Reported-by: John Stanley <jpsinthemix@verizon.net>
Tested-by: John Stanley <jpsinthemix@verizon.net>
Cc: stable@kernel.org
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
This commit is contained in:
Tejun Heo 2011-01-20 13:59:06 +01:00 committed by Jeff Garzik
parent 4a5610a04d
commit 729a6a300e
1 changed files with 18 additions and 6 deletions
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24
drivers/ata/libata-scsi.c
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@ -1099,9 +1099,9 @@ 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);
@ -1115,13 +1115,25 @@ 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 */
sdev->sector_size = ata_id_logical_sector_size(dev->id);
blk_queue_update_dma_alignment(sdev->request_queue,
sdev->sector_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);