On Thu, Mar 23 2017 at 10:33am -0400,
Christoph Hellwig <hch@xxxxxx> wrote:
> It seems like the code currently passes whatever it was using for writes
> to WRITE SAME. Just switch it to WRITE ZEROES, although that doesn't
> need any payload.
>
> Untested, and confused by the code, maybe someone who understands it
> better than me can help..
>
> Not-yet-signed-off-by: Christoph Hellwig <hch@xxxxxx>
See commit 70d6c400a ("dm kcopyd: add WRITE SAME support to dm_kcopyd_zero")
drivers/md/dm-io.c:do_region() adjusts the WRITE SAME payload to be a
single page.
So you'd want to tweak dm-io.c accordingly for WRITE ZEROES (presummably
no payload?)
Mike
> ---
> drivers/md/dm-kcopyd.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/md/dm-kcopyd.c b/drivers/md/dm-kcopyd.c
> index 9e9d04cb7d51..f85846741d50 100644
> --- a/drivers/md/dm-kcopyd.c
> +++ b/drivers/md/dm-kcopyd.c
> @@ -733,11 +733,11 @@ int dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from,
> job->pages = &zero_page_list;
>
> /*
> - * Use WRITE SAME to optimize zeroing if all dests support it.
> + * Use WRITE ZEROES to optimize zeroing if all dests support it.
> */
> - job->rw = REQ_OP_WRITE_SAME;
> + job->rw = REQ_OP_WRITE_ZEROES;
> for (i = 0; i < job->num_dests; i++)
> - if (!bdev_write_same(job->dests[i].bdev)) {
> + if (!bdev_write_zeroes_sectors(job->dests[i].bdev)) {
> job->rw = WRITE;
> break;
> }
> --
> 2.11.0
>
