[PATCH v9 06/11] io_uring: introduce attributes for read/write and PI support

[Matthew Wilcox]

On Thu, Nov 14, 2024 at 01:09:44PM +0000, Pavel Begunkov wrote:
> With SQE128 it's also a problem that now all SQEs are 128 bytes regardless
> of whether a particular request needs it or not, and the user will need
> to zero them for each request.

The way we handled this in NVMe was to use a bit in the command that
was called (iirc) FUSED, which let you use two consecutive entries for
a single command.

Some variant on that could surely be used for io_uring.  Perhaps a
special opcode that says "the real opcode is here, and this is a two-slot
command".  Processing gets a little spicy when one slot is the last in
the buffer and the next is the the first in the buffer, but that's a SMOP.