On Fri, Oct 06, 2023 at 05:19:52PM +0900, Damien Le Moal wrote: > Your change seem to assume that it makes sense to be able to combine CDL with > lifetime hints. But does it really ? Yes, it does. > CDL is of dubious value for solid state > media and as far as I know, No, it's pretty useful and I'd bet my 2 cents that it will eventually show up in relevant standards and devices. Even if it wasn't making our user interfaces exclusive would be a massive pain. > The other question here if you really want to keep the bit separation approach > is: do we really need up to 64 different lifetime hints ? While the scsi > standard allows that much, does this many different lifetime make sense in > practice ? Can we ever think of a usecase that needs more than say 8 different > liftimes (3 bits) ? If you limit the number of possible lifetime hints to 8, > then we can keep 4 bits unused in the hint field for future features. Yes, I think this is the smoking gun. We should be fine with a much more limited number of lifetime hints, i.e. the user interface only exposes 5 hints, and supporting more in the in-kernel interfaces seems of rather doubtfuŀ use.
