On Tue, Mar 18, 2025 at 12:22:57PM -0600, Jens Axboe wrote:

quoted

 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?