Subject: Re: [PATCH] af_packet: flush complete kernel cache in packet_sendmsg

From: Phil Sutter <[email-masked]>
Date: Fri, 2 Sep 2011 15:59:55 +0200

On Fri, Sep 02, 2011 at 02:46:17PM +0100, Ben Hutchings wrote:
> On Fri, 2011-09-02 at 13:08 +0200, Phil Sutter wrote:
> > This flushes the cache before and after accessing the mmapped packet
> > buffer. It seems like the call to flush_dcache_page from inside
> > __packet_get_status is not enough on Kirkwood (or ARM in general).
> > ---
> > I know this is far from an optimal solution, but it's in fact the only working
> > one I found.
> [...]
> 
> This is ridiculous.  If flush_dcache_page() isn't doing everything it
> should, you need to fix that.

You're absolutely correct. But in fact this problem goes way too deep
for me to find it's cause. And since my time is finite, I doubt this
will change in the near future. So I asked for help, a pointer in
whatever direction or anything I could try to help further analyzing -
without any response (unless I missed it, in which case I apologize).

Please don't get me wrong. I have no intend in this patch becoming
mainline, just want to give others with the same problem a starting
point.

Greetings, Phil
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