• Mike Snitzer's avatar
    dm kcopyd: add WRITE SAME support to dm_kcopyd_zero · 70d6c400
    Mike Snitzer authored
    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: default avatarMike Snitzer <snitzer@redhat.com>
    Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
dm-io.c 12.7 KB