Re: [GIT PULL] Block updates for 6.9-rc1

Christoph Hellwig
2024-03-12T22:30:35Z

On Tue, Mar 12, 2024 at 06:22:21PM -0400, Mike Snitzer wrote:
> > The real problem is that we combine the limits while we shouldn't.
> > Every since we've supported immutable biovecs and do the splitting
> > down in blk-mq there is no point to even inherit such limits in the
> > upper drivers.
>
> immutable biovecs, late splitting and blk-mq aren't a factor.
>
> dm-crypt has to contend with the crypto subsystem and HW crypto
> engines that have their own constraints.

Yes, they are. The limit for underlying device does not matter for
an upper devіce as it will split later. And that's not just my
opinion, you also clearly stated that in the commit adding the
limits (586b286b110e94e). We should have stopped inheriting all
these limits only relevant for splitting when we switched to
immutable bvecs. I don't know why we didn't, but a big part of
that might be that we never made clear which limits these are.