Re: mlockall and mmap of IO devices don't mix

Russell King
2003-10-04T09:22:27Z

On Sat, Oct 04, 2003 at 11:17:03AM +0200, Andi Kleen wrote:
> > This check is only done, if it is a valid pfn (pfn_valid()) of a present
> > pte.
>
> pfn_valid is useless, it doesn't handle all IO holes on x86 for examples.

Sounds like pfn_valid() is buggy on x86. It's supposed to definitively
indicate whether the PFN is a valid page of ram (and has a valid struct
page entry.) If it doesn't do that, the architecture implementation is
wrong.

--
Russell King (rmk@arm.linux.org.uk) http://www.arm.linux.org.uk/personal/
Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/
maintainer of: 2.6 PCMCIA - http://pcmcia.arm.linux.org.uk/
2.6 Serial core