Subject: Re: [PATCH] MIPS: Fix get_user_page_fast() for mips with cache alias

From: Kevin Cernekee <[email-masked]>
Date: Fri, 19 Jul 2013 08:34:50 -0700

On Tue, Jun 18, 2013 at 9:47 AM, Ralf Baechle <[email-masked]> wrote:
> On Fri, Jun 14, 2013 at 02:10:03PM -0400, Kamal Dasu wrote:
>
>> get_user_pages_fast() is missing cache flushes for MIPS platforms
>> with cache alias. Filesystem failures observed with DirectIO
>> operations due to missing flush_anon_page() that use page coloring
>> logic to work with cache aliases. This fix falls through to take
>> slow_irqon path that calls get_user_pages() that has required
>> logic for platforms where cpu_has_dc_aliases is true.
>
> A bit unsatisfying to always fall back to the slow variant yet I like
> the patch because of it's simplicity but I wonder if there's not a
> better solution.

Hi Ralf,

What are your thoughts on pushing this fix to the stable tree for
3.4+?  Without Kamal's patch, ntfs-3g is completely broken on MIPS
platforms that have cache aliases.

Thanks.