io_uring: move req async preparation into opcode handler

Define an io_op_def->prep_async() handler and push the async preparation
to there. Since we now have that, we can drop ->needs_async_setup, as
they mean the same thing.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2022-05-23 17:30:37 -06:00
commit dc919caff6