io_uring: buffer registration infrastructure

This just prepares the ring for having lists of buffers associated with
it, that the application can provide for SQEs to consume instead of
providing their own.

The buffers are organized by group ID.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2020-02-23 16:23:11 -07:00
commit 5a2e745d4d