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From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Stefan Richter <stefanr@s5r6.in-berlin.de>
Subject: Re: [PATCH 3/4] firewire: enforce access order between generation and node ID
Date: Thu, 24 Jan 2008 15:55:30 +1100
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       Kristian =?iso-8859-1?q?H=F8gsberg?= <krh@redhat.com>,
       Jarod Wilson <jwilson@redhat.com>
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On Thursday 24 January 2008 11:54, Stefan Richter wrote:
> fw_device.node_id and fw_device.generation are accessed without mutexes.
> We have to ensure that all readers will get to see node_id updates
> before generation updates.
>
> An earlier incarnation of this patch fixes an inability to recognize
> devices after "giving up on config rom",
> https://bugzilla.redhat.com/show_bug.cgi?id=429950
>
> Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
> ---
>
> Rework of patches
>     firewire: fw-core: enforce write order when updating
> fw_device.generation and parts of
>     firewire: fw-core: react on bus resets while the config ROM is being
> fetched firewire: fw-sbp2: enforce read order of device generation and node
> ID from November 1 2007.
>
> Update:
>   - write site and read sites folded into one patch
>   - added fix to fw_device_enable_phys_dma() and fill_bus_reset_event()
>   - smp_ barriers are sufficient
>   - comments, changelog

I don't know the firewire subsystem at all, but the barriers seem
right (in that they match your description of the problem), and
comments for them are really good.

Thanks,
Nick