On Thu, Oct 28, 2021 at 09:13:07AM -0600, Jens Axboe wrote:

A couple of suggestions on this:

1) Don't think we need an IOSQE flag, those are mostly reserved for
   modifiers that apply to (mostly) all kinds of requests
2) I think this would be cleaner as a separate command, rather than
   need odd adjustments and iov assumptions. That also gets it out
   of the fast path.

I'd add IORING_OP_READV_PI and IORING_OP_WRITEV_PI for this, I think
you'd end up with a much cleaner implementation that way.

Agreed.  I also wonder if we could do saner paramter passing.
E.g. pass a separate pointer to the PI data if we find space for
that somewhere in the SQE.