Re: [PATCH v2 tip/core/rcu 07/13] ipv6/ip6_tunnel: Applyrcu_access_pointer() to avoid sparse false positive

[Eric Dumazet]

On Wed, 2013-10-09 at 14:57 -0700, Paul E. McKenney wrote:

> Hmmm...  I could use RCU_INIT_POINTER().  Something like the following?
> 
> 	RCU_INIT_POINTER(ACCESS_ONCE(*tp), t->next);
> 
> The ACCESS_ONCE() to prevent the compiler from doing anything stupid.
> Presumably the value of t->next cannot change, so a normal load suffices.
> 
> Or did you have something else in mind?

Well, *tp and t->next are both of the same type, with __rcu attribute.

struct ip6_tnl __rcu **tp;

So I meant :

ACCESS_ONCE(*tp) = t->next;

If really we can have a really stupid compiler.


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