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authorMartin K. Petersen <martin.petersen@oracle.com>2014-06-03 18:45:51 -0400
committerChristoph Hellwig <hch@lst.de>2014-07-17 22:07:33 +0200
commitbcdb247c6b6a1f3e72b9b787b73f47dd509d17ec (patch)
tree00131e8131aaeb1a94c61556dfb87ded905dd5e3 /drivers/scsi/sd.c
parent8d964478b2d124fcfde8017d02d4d70ae20802f2 (diff)
sd: Limit transfer length
Until now the per-command transfer length has exclusively been gated by the max_sectors parameter in the scsi_host template. Given that the size of this parameter has been bumped to an unsigned int we have to be careful not to exceed the target device's capabilities. If the if the device specifies a Maximum Transfer Length in the Block Limits VPD we'll use that value. Otherwise we'll use 0xffffffff for devices that have use_16_for_rw set and 0xffff for the rest. We then combine the chosen disk limit with max_sectors in the host template. The smaller of the two will be used to set the max_hw_sectors queue limit. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Ewan D. Milne <emilne@redhat.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'drivers/scsi/sd.c')
-rw-r--r--drivers/scsi/sd.c16
1 files changed, 15 insertions, 1 deletions
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 5167b9678240..87566b51fcf7 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2236,7 +2236,11 @@ got_data:
}
}
- sdp->use_16_for_rw = (sdkp->capacity > 0xffffffff);
+ if (sdkp->capacity > 0xffffffff) {
+ sdp->use_16_for_rw = 1;
+ sdkp->max_xfer_blocks = SD_MAX_XFER_BLOCKS;
+ } else
+ sdkp->max_xfer_blocks = SD_DEF_XFER_BLOCKS;
/* Rescale capacity to 512-byte units */
if (sector_size == 4096)
@@ -2551,6 +2555,7 @@ static void sd_read_block_limits(struct scsi_disk *sdkp)
{
unsigned int sector_sz = sdkp->device->sector_size;
const int vpd_len = 64;
+ u32 max_xfer_length;
unsigned char *buffer = kmalloc(vpd_len, GFP_KERNEL);
if (!buffer ||
@@ -2558,6 +2563,10 @@ static void sd_read_block_limits(struct scsi_disk *sdkp)
scsi_get_vpd_page(sdkp->device, 0xb0, buffer, vpd_len))
goto out;
+ max_xfer_length = get_unaligned_be32(&buffer[8]);
+ if (max_xfer_length)
+ sdkp->max_xfer_blocks = max_xfer_length;
+
blk_queue_io_min(sdkp->disk->queue,
get_unaligned_be16(&buffer[6]) * sector_sz);
blk_queue_io_opt(sdkp->disk->queue,
@@ -2712,6 +2721,7 @@ static int sd_revalidate_disk(struct gendisk *disk)
struct scsi_disk *sdkp = scsi_disk(disk);
struct scsi_device *sdp = sdkp->device;
unsigned char *buffer;
+ unsigned int max_xfer;
SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp,
"sd_revalidate_disk\n"));
@@ -2759,6 +2769,10 @@ static int sd_revalidate_disk(struct gendisk *disk)
*/
sd_set_flush_flag(sdkp);
+ max_xfer = min_not_zero(queue_max_hw_sectors(sdkp->disk->queue),
+ sdkp->max_xfer_blocks);
+ max_xfer <<= ilog2(sdp->sector_size) - 9;
+ blk_queue_max_hw_sectors(sdkp->disk->queue, max_xfer);
set_capacity(disk, sdkp->capacity);
sd_config_write_same(sdkp);
kfree(buffer);