On Wed, Oct 2, 2024, at 16:04, Greg Kroah-Hartman wrote: > On Wed, Oct 02, 2024 at 03:45:08PM +0000, Arnd Bergmann wrote: >> On Wed, Oct 2, 2024, at 14:23, Christian Brauner wrote: >> >> Here, the 64-bit 'old' has the same size as the 32-bit 'new', >> so if we try to handle them in a shared native/compat ioctl >> function, this needs an extra in_conmpat_syscall() check that >> adds complexity and is easy to forget. > > Agreed, "extending" ioctls is considered a bad thing and it's just > easier to create a new one. Or use some flags and reserved fields, if > you remember to add them in the beginning... > > Anyway, this is all great, but for now, I'll take this series in my tree > and we can add onto it from there. I'll dig up some sample code that > uses this too, so that we make sure it works properly. Give me a few > days to catch up before it lands in my trees... Sounds good to me, it's clear we don't get a quick solution and there is nothing stopping us from revisiting this after we have a couple of drivers using ioctl. Arnd