> Date: Fri, 30 Sep 2005 07:28:36 +1000
> From: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
> On Thu, Sep 29, 2005 at 09:02:29AM -0700, Suzanne Wood wrote:
> >
> > The exchange below suggests that it is equally important
> > to have the rcu_dereference() in __in_dev_get(), so the
> > idea of the only difference between in_dev_get and
> > __in_dev_get being the refcnt may be accepted.
> With __in_dev_get() it's the caller's responsibility to ensure
> that RCU works correctly. Therefore if any rcu_dereference is
> needed it should be done by the caller.
This sounds reasonable to me. Does everyone agree?
> Some callers of __in_dev_get() don't need rcu_dereference at all
> because they're protected by the rtnl.
> BTW, could you please move the rcu_dereference in in_dev_get()
> into the if clause? The barrier is not needed when ip_ptr is
> NULL.
The trouble with that may be that there are three events, the
dereference, the assignment, and the conditional test. The
rcu_dereference() is meant to assure deferred destruction
throughout.
Thank you very much for your suggestions.
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