On Mon, 2014-06-02 at 15:11 -0400, Martin K. Petersen wrote:
> 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@xxxxxxxxxx>
>
> diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
> index 321faf603035..56018f37518d 100644
> --- a/drivers/scsi/sd.c
> +++ b/drivers/scsi/sd.c
> @@ -2228,7 +2228,11 @@ 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)
> @@ -2540,6 +2544,7 @@ 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 ||
> @@ -2547,6 +2552,10 @@ 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,
> @@ -2702,6 +2711,7 @@ static int sd_revalidate_disk(struct gendisk *disk)
> struct scsi_device *sdp = sdkp->device;
> unsigned char *buffer;
> unsigned flush = 0;
> + unsigned int max_xfer;
>
> SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp,
> "sd_revalidate_disk\n"));
> @@ -2755,6 +2765,10 @@ static int sd_revalidate_disk(struct gendisk *disk)
>
> blk_queue_flush(sdkp->disk->queue, flush);
>
> + max_xfer = min_not_zero((unsigned int)sdp->host->max_sectors,
> + (unsigned int)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);
> diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
> index 620871efbf0a..4c3ab8377fd3 100644
> --- a/drivers/scsi/sd.h
> +++ b/drivers/scsi/sd.h
> @@ -44,6 +44,8 @@ enum {
> };
>
> enum {
> + SD_DEF_XFER_BLOCKS = 0xffff,
> + SD_MAX_XFER_BLOCKS = 0xffffffff,
> SD_MAX_WS10_BLOCKS = 0xffff,
> SD_MAX_WS16_BLOCKS = 0x7fffff,
> };
> @@ -64,6 +66,7 @@ struct scsi_disk {
> struct gendisk *disk;
> atomic_t openers;
> sector_t capacity; /* size in 512-byte sectors */
> + u32 max_xfer_blocks;
> u32 max_ws_blocks;
> u32 max_unmap_blocks;
> u32 unmap_granularity;
> --
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Looks good.
Reviewed-by: Ewan D. Milne <emilne@xxxxxxxxxx>
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