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Commit 729a6a30 authored by Tejun Heo's avatar Tejun Heo Committed by Jeff Garzik
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libata: set queue DMA alignment to sector size for ATAPI too 



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: default avatarTejun Heo <tj@kernel.org>
Reported-by: default avatarJohn Stanley <jpsinthemix@verizon.net>
Tested-by: default avatarJohn Stanley <jpsinthemix@verizon.net>
Cc: stable@kernel.org
Signed-off-by: default avatarJeff Garzik <jgarzik@redhat.com>
parent 4a5610a0

drivers/ata/libata-scsi.c

+18 −6
Original line number Original line Diff line number Diff line
@@ -1099,9 +1099,9 @@ static int ata_scsi_dev_config(struct scsi_device *sdev, 
		struct request_queue *q = sdev->request_queue;

		struct request_queue *q = sdev->request_queue;

		void *buf;

		void *buf;





		/* set the min alignment and padding */

		sdev->sector_size = ATA_SECT_SIZE;

		blk_queue_update_dma_alignment(sdev->request_queue,



					       ATA_DMA_PAD_SZ - 1);

		/* set DMA padding */

		blk_queue_update_dma_pad(sdev->request_queue,

		blk_queue_update_dma_pad(sdev->request_queue,

					 ATA_DMA_PAD_SZ - 1);

					 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);

		blk_queue_dma_drain(q, atapi_drain_needed, buf, ATAPI_MAX_DRAIN);

	} else {

	} else {

		/* ATA devices must be sector aligned */

		sdev->sector_size = ata_id_logical_sector_size(dev->id);

		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;

		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)

	if (dev->flags & ATA_DFLAG_AN)

		set_bit(SDEV_EVT_MEDIA_CHANGE, sdev->supported_events);

		set_bit(SDEV_EVT_MEDIA_CHANGE, sdev->supported_events);