On Thu, Mar 23, 2017 at 03:43:30PM +0100, Christoph Hellwig wrote:

I tried this earlier before giving up on it because it looked to ugly.
But I can complete that version of it and post it for people to compare.

Meh, I remember why I gave up on it - to support queued trim passthrough
we'd need to implement ATA 32 for the auxiliary fields and thus support
32-bit CDBs.  I don't really want to go there..