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authorTejun Heo <htejun@gmail.com>2011-01-20 13:59:06 +0100
committerGreg Kroah-Hartman <gregkh@suse.de>2011-05-09 15:55:41 -0700
commit162231ba4bb635759c3edcb1dc81a02b192c5e05 (patch)
parent63de1f2c9f4b5b47893c425579321657400b98a0 (diff)
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 <tj@kernel.org> Reported-by: John Stanley <jpsinthemix@verizon.net> Tested-by: John Stanley <jpsinthemix@verizon.net> Signed-off-by: Jeff Garzik <jgarzik@redhat.com> Signed-off-by: Jonathan Liu <net147@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
1 files changed, 18 insertions, 6 deletions
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index a158a6c925d0..553edccbe89d 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 */
@@ -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,
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);