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Subject: Re: [PATCH 1/2 v2] WARN_ON_SMP(): Allow use in if statements on UP
From: Peter Zijlstra <peterz@infradead.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
        Andrew Morton <akpm@linux-foundation.org>,
        Thomas Gleixner <tglx@linutronix.de>,
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        Darren Hart <dvhart@linux.intel.com>
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Date: Fri, 18 Mar 2011 10:12:18 +0100
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On Thu, 2011-03-17 at 17:56 -0400, Steven Rostedt wrote:
> + * WARN_ON(!spin_is_locked(&lock)) checks, as spin_is_locked()
> + * returns 0 for uniprocessor settings. 

Arguably most spin_is_locked() usages should be removed in favour of
something like lockdep_assert_held().

The latter only emits code then built with lockdep enabled and it checks
we are indeed the owner, not some random other cpu.