[PATCHSET v3] Add direct descriptor ring passing

[Jens Axboe <axboe@xxxxxxxxx>]

Hi,

Hi,

One of the things we currently cannot do with direct descriptors is pass
it to another application or ring. This adds support for doing so, through
the IORING_OP_MSG_RING ring-to-ring messaging opcode.

Changes since v2:
- Add flag for controlling whether to post a CQE to the target ring or
  not.

-- 
Jens Axboe