On 14-06-02 09:56 AM, Akinobu Mita wrote:
This change enables to test read/write commands with huge transfer
length such as 1GB.  For example:

        # modprobe scsi_debug dev_size_mb=1024 clustering=1 opts=1
        # cat /sys/block/$DEV/queue/max_hw_sectors_kb > \
                /sys/block/$DEV/queue/max_sectors_kb
        # fio --name=test --rw=write --bs=1g --size=1g --filename=/dev/$DEV \
                --mem=mmaphuge  --direct=1

The data type of max_sectors in scsi_host_template has been extended
to unsigned int by the previous change.  So we can increase it from
0xffff to 0xffffffff to allow such huge transfer length.

Also, this increases sg_tablesize and max_segment_size, otherwise the
maximum transfer length is limited to 64MB.
(sg_tablesize * max_segment_size = 256 * 256KB)

Signed-off-by: Akinobu Mita <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: "James E.J. Bottomley" <[email protected]>
Cc: Douglas Gilbert <[email protected]>
Cc: [email protected]

Acked by: Douglas Gilbert <[email protected]>

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