Re: [RFC PATCH v3 3/3] nvme: wire up support for async passthrough

[Jens Axboe <axboe@kernel.dk>]

On 3/17/21 11:21 AM, Jens Axboe wrote:
> On 3/17/21 10:59 AM, Christoph Hellwig wrote:
>> On Wed, Mar 17, 2021 at 10:49:28AM -0600, Jens Axboe wrote:
>>> I will post it soon, only reason I haven't reposted is that I'm not that
>>> happy with how the sqe split is done (and that it's done in the first
>>> place). But I'll probably just post the current version for comments,
>>> and hopefully we can get it to where it needs to be soon.
>>
>> Yes, I don't like that at all either.  I almost wonder if we should
>> use an entirely different format after opcode and flags, although
>> I suspect fd would be nice to have in the same spot as well.
> 
> Exactly - trying to think of how best to do this. It's somewhat a shame
> that I didn't place user_data right after fd, or even at the end of the
> struct. But oh well.
> 
> One idea would be to have io_uring_sqe_hdr and have that be
> op/flags/prio/fd as we should have those for anything, and just embed
> that at the top of both io_uring_sqe (our general command), and
> io_uring_whatever which is what the passthrough stuff would use.
> 
> Not sure, I need to dabble in the code a bit and see how we can make it
> the cleanest.

How about something like the top two patches here to kick it off, then
build on top?

https://git.kernel.dk/cgit/linux-block/log/?h=io_uring-fops.v4

-- 
Jens Axboe