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Date: Tue, 3 Apr 2018 09:11:34 -0700
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: David Howells <dhowells@redhat.com>,
        Andrea Parri <andrea.parri@amarulasolutions.com>,
        Ingo Molnar <mingo@redhat.com>, linux-kernel@vger.kernel.org,
        Andrea Parri <parri.andrea@gmail.com>,
        Alan Stern <stern@rowland.harvard.edu>,
        Will Deacon <will.deacon@arm.com>, Boqun Feng <boqun.feng@gmail.com>,
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        Jade Alglave <j.alglave@ucl.ac.uk>,
        Luc Maranget <luc.maranget@inria.fr>,
        Akira Yokosawa <akiyks@gmail.com>
Subject: Re: [PATCH v2 1/3] locking: Document the semantics of
 spin_is_locked()
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On Tue, Apr 03, 2018 at 08:03:56AM -0700, Paul E. McKenney wrote:
> On Tue, Apr 03, 2018 at 04:43:00PM +0200, Peter Zijlstra wrote:
> > On Tue, Apr 03, 2018 at 07:17:18AM -0700, Paul E. McKenney wrote:
> > > Suggestions for a fix?  Clearly great care is required when using it
> > > in things like WARN_ON()...
> > 
> > Yeah, don't use it there, use lockdep_assert_held().
> 
> Good point, -ETOOEARLY.  ;-)
> 
> > As I stated before in this thread, ideally we'd make *_is_locked() go
> > away entirely.
> 
> After being reminded of the issues on UP systems, I now have much more
> sympathy for that view...

And so the main remaining use case is debug prints on !PROVE_LOCKING
builds.  Which need some thought about the UP case.

Or am I missing something here?

							Thanx, Paul