On Tue, Mar 21, 2017 at 02:59:01PM -0400, Tejun Heo wrote: > I do like the fact that this is a lot simpler than the previous > implementation but am not quite sure we want to deviate significantly > from what we do for other commands (command translation). Is it > because fixing the existing implementation would involve invaisve > changes including memory allocations?
The current implementation already has the issue of that it does corrupt user data reliably if the using SG_IO for WRITE SAME commands. Doing ranges using translation would turn into a nightmare because ATA TRIM ranges are 16 bits long while SCSI UNAMP ranges are 32-bit, so we effectively can't translated them without introducing a non-standard hook between libata and scsi to communicate that limit. And once we're down that path we might as well just do the right thing directly.
