Re: [PATCH] ublk: remove io_cmds list in ublk_queue

[Uday Shankar <ushankar@purestorage.com>]

On Tue, Mar 18, 2025 at 12:22:57PM -0600, Jens Axboe wrote:
> >  struct ublk_rq_data {
> > -	struct llist_node node;
> > -
> >  	struct kref ref;
> >  };
> 
> Can we get rid of ublk_rq_data then? If it's just a ref thing, I'm sure
> we can find an atomic_t of space in struct request and avoid it. Not a
> pressing thing, just tossing it out there...

Yeah probably - we do need a ref since one could complete a request
concurrently with another code path which references it (user copy and
zero copy). I see that struct request has a refcount in it already,
though I don't see any examples of drivers using it. Would it be a bad
idea to try and reuse that?