On Wed, 8 Jun 2022 19:21:05 +0100 Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote: > > Perhaps some magic happened with cpp's recognition of include guards? > > I had some time to look at this now. It's picking up > /usr/include/linux/limits.h on my machine which is provided by > linux-libc-dev. That's a rather different set of constants from the ones > the kernel provides internally, which might cause problems later. But I'm > not in a mood to go poking around the different locations that different > environments provide things in, so I think this patch is OK. Thanks. I don't think it's good to be replacing our limits.h with some random system-provided one. I'll drop the patch.