[PATCH 2/2] nvme: add emulation for zone-append

[Keith Busch]

On Wed, Aug 19, 2020 at 01:11:58PM -0600, David Fugate wrote:
> Intel does not support making *optional* NVMe spec features *required*
> by the NVMe driver. 

This is inaccurate. As another example, the spec optionally allows a
zone size to be a power of 2, but linux requires a power of 2 if you
want to use it with this driver.

> Provided there's no glaring technical issues

There are many. Some may be improved through a serious review process,
but the mess it makes out of the fast path is measurably harmful to
devices that don't subscribe to this. That issue is not so easily
remedied.

Since this patch is a copy of the scsi implementation, the reasonable
thing is take this fight to the generic block layer for a common
solution. We're not taking this in the nvme driver.