On Mon, Apr 08, 2024 at 03:36:50PM +0800, Ming Lei wrote: > It isn't now we put the limit, and this way has been done for stacking device > since beginning, it is actually added by commit d690cb8ae14b in v6.9-rc1. > > If max segment size isn't aligned with virt_boundary_mask, bio_split_rw() > will split the bio with max segment size, this way still works, just not > efficiently. And in reality, the two are often aligned. We've had real bugs due to this, which is why we have the check. We also had a warning before the commit, it's just it got skipped for stacking. So even if we want to return to the broken pre-6.9-rc behavior it should only be for stacking. I don't think that is a good outcome, though.