Re: [LSF/MM/BPF TOPIC] block drivers in user space

[Hannes Reinecke <hare@suse.de>]

On 3/2/22 17:52, Mike Christie wrote:
> On 2/21/22 1:59 PM, Gabriel Krisman Bertazi wrote:
>> I'd like to discuss an interface to implement user space block devices,
>> while avoiding local network NBD solutions.  There has been reiterated
> 
> Besides the tcmu approach, I've also worked on the local nbd based
> solution like here:
> 
> https://github.com/gluster/nbd-runner
> 
> Have you looked into a modern take that uses io_uring's socket features
> with the zero copy work that's being worked on for it? If so, what are
> the issues you have hit with that? Was it mostly issues with the zero
> copy part of it?
> 
> 
Problem is that we'd need an _inverse_ io_uring interface.
The current io_uring interface writes submission queue elements,
and waits for completion queue elements.

For this use-case we'd need to convert it to wait for submission queue 
elements, and write completion queue elements.

IE completely invert the operation.

Not sure if we can convert it _that_ easily ...

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
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