rcu: Documentation update

[~andy/linux] / Documentation / RCU / lockdep.txt

diff --git a/Documentation/RCU/lockdep.txt b/Documentation/RCU/lockdep.txt
index a102d4b3724bad454250d5d9e4ae883818725d91..cd83d2348fef8c4a3ff3bee57fc9904976b46390 100644 (file)
--- a/Documentation/RCU/lockdep.txt
+++ b/Documentation/RCU/lockdep.txt
@@ -64,6 +64,11 @@ checking of rcu_dereference() primitives:
                but retain the compiler constraints that prevent duplicating
                or coalescsing.  This is useful when when testing the
                value of the pointer itself, for example, against NULL.
+       rcu_access_index(idx):
+               Return the value of the index and omit all barriers, but
+               retain the compiler constraints that prevent duplicating
+               or coalescsing.  This is useful when when testing the
+               value of the index itself, for example, against -1.
 
 The rcu_dereference_check() check expression can be any boolean
 expression, but would normally include a lockdep expression.  However,