On Fri, Oct 28, 2016 at 2:07 PM, Arnd Bergmann [off-list ref] wrote:

quoted

quoted

I don't think that's an accurate statement. In terms of coverage, most
drivers do support blk-mq. Anything SCSI, nvme, virtio-blk, SATA runs on
(or can run on) top of blk-mq.

Well, I just used "git grep" and found that many drivers didn't use
blkmq. Apologize if I gave the wrong impressions.

To clarify, this seems to be a complete list:

$ git grep -wl '\(__\|\)blk_\(fetch\|end\|start\)_request' | xargs grep -L blk_mq
Documentation/scsi/scsi_eh.txt
arch/um/drivers/ubd_kern.c

AFAICT Daniel looked at the UML block driver and did an initial
conversion some time ago.
Daniel?
Anton is also working on a patch series to speed up the driver.
Maybe it is time to bite the bullet and do the conversion.

-- 
Thanks,
//richard