Subject: Re: linux-next: build failure after merge of the rcu tree

From: "Paul E. McKenney" <[email-masked]>
Date: Fri, 11 Aug 2017 07:39:17 -0700

On Fri, Aug 11, 2017 at 11:14:34AM +0200, Peter Zijlstra wrote:
> On Thu, Aug 10, 2017 at 09:54:53PM -0700, Paul E. McKenney wrote:
> > On Fri, Aug 11, 2017 at 02:43:52PM +1000, Stephen Rothwell wrote:
> > 
> > Looks like I need to rebase my patch on top of a9668cd6ee28, and
> > than put an smp_mb__after_spinlock() between the lock and the unlock.
> > 
> > Peter, any objections to that approach?  Other suggestions?
> 
> Hurm.. I'll have to try and understand that comment there again it
> seems.

My reasoning is as follows:

1.	The critical section is empty, so any prior references
	would be ordered only against later critical sections.

2.	A full barrier within the critical section will order those
	prior references against later critical sections just
	as easily as would one prior to the critical section.

Does that make sense, I should I have stayed away from the keyboard
at this early hour?  ;-)

							Thanx, Paul