Re: BUG? linux-mips flush_dcache_page

From: Ralf Baechle
Date: Fri Oct 16 2009 - 05:24:14 EST


On Fri, Oct 16, 2009 at 02:17:19PM +0900, Minchan Kim wrote:

> Many code of kernel fs usually allocate high page and flush.
> But flush_dcache_page of mips checks PageHighMem to avoid flush
> so that data consistency is broken, I think.

What processor and cache configuration?

> I found it's by you and Atsushi-san on 585fa724.
> Why do we need the check?
> Could you elaborte please?

The if statement exists because __flush_dcache_page would crash if a page
is not mapped. This of course isn't correct but that wasn't a problem
since highmem still is only supported on machines that don't have aliases.

Ralf
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