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From: Arnd Bergmann on 4 May 2010 17:50
On Tuesday 04 May 2010 23:26:31 Stephen Hemminger wrote:
> > The new versions of the rcu_dereference() APIs requires that any pointers
> > passed to one of these APIs be fully defined. The ->br_port field
> > in struct net_device points to a struct net_bridge_port, which is an
> > incomplete type. This commit therefore changes ->br_port to be a void*,
> > and introduces a br_port() helper function to convert the type to struct
> > net_bridge_port, and applies this new helper function where required.
> >
>
> I would rather make the bridge hook generic and not take a type argument.

Not sure if you were confused by the comment in the same way that I was.

The bridge hook is not impacted by this at all, since we can either pass
a void* or a struct net_bridge_port* to it. The br_port() helper
is used for all the places where we actually want to dereference
dev->br_port and access its contents.

Arnd
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From: Arnd Bergmann on 6 May 2010 10:20
On Thursday 06 May 2010, Paul E. McKenney wrote:
> On Tue, May 04, 2010 at 11:41:49PM +0200, Arnd Bergmann wrote:
> > On Tuesday 04 May 2010 23:26:31 Stephen Hemminger wrote:
> > > > The new versions of the rcu_dereference() APIs requires that any pointers
> > > > passed to one of these APIs be fully defined. The ->br_port field
> > > > in struct net_device points to a struct net_bridge_port, which is an
> > > > incomplete type. This commit therefore changes ->br_port to be a void*,
> > > > and introduces a br_port() helper function to convert the type to struct
> > > > net_bridge_port, and applies this new helper function where required.
> > >
> > > I would rather make the bridge hook generic and not take a type argument.
> >
> > Not sure if you were confused by the comment in the same way that I was.
> >
> > The bridge hook is not impacted by this at all, since we can either pass
> > a void* or a struct net_bridge_port* to it. The br_port() helper
> > is used for all the places where we actually want to dereference
> > dev->br_port and access its contents.
>
> What should I change in the commit message to clear this up?
>
> Of course, if the code needs to change, please let me know what should
> change there as well.

I think it's both ok, I was mostly confused by the discussion we had earlier.
Maybe add a sentence like:

The br_handle_frame_hook now needs a forward declaration of struct net_bridge_port.

Or you just change br_handle_frame_hook to take a void* to avoid the forward
declaration. Not sure what Stephen was referring to really.

Arnd
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