Re: [PATCH tip/urgent] rcu: add rcu_access_pointer andrcu_dereference_protected

[Paul E. McKenney]

On Wed, Apr 07, 2010 at 04:00:09PM -0700, Paul E. McKenney wrote:
> On Wed, Apr 07, 2010 at 06:20:48PM +0100, David Howells wrote:
> > Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> wrote:
> > 
> > > In other cases, there will be a reference counter or a "not yet fully
> > > initialized" flag that can (and should) be tested.
> > 
> > Why would you be using rcu_access_pointer() there?  Why wouldn't you be using
> > rcu_dereference_protected()?
> 
> Excellent question.  I am writing up the documentation now, and will
> either (1) have a good use case or (2) remove the condition.

And all of the examples I could come up with that had c!=1 were contorted,
even by my standards.  So you were right, and I will drop the "c" on my
next set of patches.

							Thanx, Paul
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