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Re: [PATCH] Apply kmap_high_get with MIPS

To: "Dezhong Diao (dediao)" <dediao@cisco.com>
Subject: Re: [PATCH] Apply kmap_high_get with MIPS
From: Kevin Cernekee <cernekee@gmail.com>
Date: Thu, 27 May 2010 11:24:07 -0700
Cc: linux-mips@linux-mips.org
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On Mon, May 3, 2010 at 4:40 PM, Dezhong Diao (dediao) <dediao@cisco.com> wrote:
> +               addr = (unsigned long)kmap_high_get(page);
> +               if (addr) {
> +                       addr += offset;
> +                       __dma_sync_virtual(addr, size, direction);
> +                       kunmap_high(page);
> +               }

When addr == 0, no flush is performed and that results in serious
coherency problems on my system.

The latest ARM code has a special "VIPT" handler for this case; I
suspect that MIPS needs something similar:

http://lists.infradead.org/pipermail/linux-arm-kernel/2010-March/012169.html

My cache is VIPT with no aliases.

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