dm kcopyd: add WRITE SAME support to dm_kcopyd_zero
Add WRITE SAME support to dm-io and make it accessible to dm_kcopyd_zero(). dm_kcopyd_zero() provides an asynchronous interface whereas the blkdev_issue_write_same() interface is synchronous. WRITE SAME is a SCSI command that can be leveraged for more efficient zeroing of a specified logical extent of a device which supports it. Only a single zeroed logical block is transfered to the target for each WRITE SAME and the target then writes that same block across the specified extent. The dm thin target uses this. Signed-off-by:Mike Snitzer <snitzer@redhat.com> Signed-off-by:
Alasdair G Kergon <agk@redhat.com>
parent
4f0b70b0
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