[dm-devel] [RFC PATCH 3/3] nvme: add the "debug" host driver

[Chaitanya Kulkarni]

Mikulas,

On 2/3/22 12:57, Mikulas Patocka wrote:
> 
> 
> On Thu, 3 Feb 2022, Luis Chamberlain wrote:
> 
>> On Thu, Feb 03, 2022 at 05:15:34PM +0100, Christoph Hellwig wrote:
>>> On Thu, Feb 03, 2022 at 08:06:33AM -0800, Luis Chamberlain wrote:
>>>> On Wed, Feb 02, 2022 at 06:01:13AM +0000, Adam Manzanares wrote:
>>>>> BTW I think having the target code be able to implement simple copy without
>>>>> moving data over the fabric would be a great way of showing off the command.
>>>>
>>>> Do you mean this should be implemented instead as a fabrics backend
>>>> instead because fabrics already instantiates and creates a virtual
>>>> nvme device? And so this would mean less code?
>>>
>>> It would be a lot less code.  In fact I don't think we need any new code
>>> at all.  Just using nvme-loop on top of null_blk or brd should be all
>>> that is needed.
>>
>> Mikulas,
>>
>> That begs the question why add this instead of using null_blk with
>> nvme-loop?
>>
>>    Luis
> 
> I think that nvme-debug (the patch 3) doesn't have to be added to the
> kernel.
> 
> Nvme-debug was an old student project that was canceled. I used it because
> it was very easy to add copy offload functionality to it - adding this
> capability took just one function with 43 lines of code (nvme_debug_copy).
> 
> I don't know if someone is interested in continuing the development of
> nvme-debug. If yes, I can continue the development, if not, we can just
> drop it.
> 
> Mikulas
> 

Thanks for explanation seems like we are on the same page, we don't
want any code such as this that is controller specific in the
NVMe repo including target.

-ck