From ac7c8e3dd2ed6489be1f6bc722029fb4855c3a34 Mon Sep 17 00:00:00 2001
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Date: Fri, 11 Oct 2013 10:17:39 -0700
Subject: [PATCH] rcu: Add comment on evaluate-once properties of
 rcu_assign_pointer().

The rcu_assign_pointer() macro, as with most cpp macros, must not evaluate
its argument more than once.  And it in fact does not.  But this might
not be obvious to the casual observer, because one of the arguments
appears no less than three times.  However, but one expansion is only
visible to sparse (__CHECKER__), and one lives inside a typeof (where
it will never be evaluated), so this is in fact safe.

This commit therefore adds a comment making this explicit.

Reported-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
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Reading git-format-patch failed