Messages in this thread | | | Date | Thu, 6 May 2010 16:12:11 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH tip/core/rcu 28/48] net: Make accesses to ->br_port safe for sparse RCU |
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On Thu, May 06, 2010 at 04:09:25PM +0200, Arnd Bergmann wrote: > 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.
Done!
> 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.
This sounds like a way to make things quite a bit more intrusive, so holding off on this.
Thanx, Paul
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