Re: [PATCH 4/6] nvmet: add Verify emulation support for bdev-ns

Chaitanya Kulkarni
2022-07-06T04:10:00Z

On 7/5/22 01:35, Christoph Hellwig wrote:
> On Thu, Jun 30, 2022 at 02:14:04AM -0700, Chaitanya Kulkarni wrote:
>> Not all devices can support verify requests which can be mapped to
>> the controller specific command. This patch adds a way to emulate
>> REQ_OP_VERIFY for NVMeOF block device namespace. We add a new
>> workqueue to offload the emulation.
>
> How is this an "emulation"?

since verify command for NVMe does everything that read does except
transferring the data, so if controller does not support verify
this implementation drops down to issuing the read command ..

>
> Also why do we need the workqueue offloads? I can't see any good
> reason to not just simply submit the bio asynchronously like all the
> other bios submitted by the block device backend.

okay will remove the workqueue ...

-ck