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authorMark Brown <broonie@opensource.wolfsonmicro.com>2011-04-18 18:07:43 +0100
committerMark Brown <broonie@opensource.wolfsonmicro.com>2011-04-18 18:07:43 +0100
commitd5381e42f64ca19f05c5799ffae5708acb6ed411 (patch)
tree8b5e757a9847047102c475c6c583afc191d02e5b /include/linux/rcupdate.h
parentf030d60b30855e18ac5bf080fa9e576147623d18 (diff)
parentb3c27b51db9112d03864fdef44fa611dd69c1425 (diff)
ASoC: Merge branch 'for-2.6.39' into for-2.6.40
Fix trivial conflict caused by silly spelling fix patch. Conflicts: sound/soc/codecs/wm8994.c
Diffstat (limited to 'include/linux/rcupdate.h')
-rw-r--r--include/linux/rcupdate.h20
1 files changed, 20 insertions, 0 deletions
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index af5614856285..ff422d2b7f90 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -339,6 +339,12 @@ extern int rcu_my_thread_group_empty(void);
((typeof(*p) __force __kernel *)(p)); \
})
+#define __rcu_access_index(p, space) \
+ ({ \
+ typeof(p) _________p1 = ACCESS_ONCE(p); \
+ rcu_dereference_sparse(p, space); \
+ (_________p1); \
+ })
#define __rcu_dereference_index_check(p, c) \
({ \
typeof(p) _________p1 = ACCESS_ONCE(p); \
@@ -429,6 +435,20 @@ extern int rcu_my_thread_group_empty(void);
#define rcu_dereference_raw(p) rcu_dereference_check(p, 1) /*@@@ needed? @@@*/
/**
+ * rcu_access_index() - fetch RCU index with no dereferencing
+ * @p: The index to read
+ *
+ * Return the value of the specified RCU-protected index, but omit the
+ * smp_read_barrier_depends() and keep the ACCESS_ONCE(). This is useful
+ * when the value of this index is accessed, but the index is not
+ * dereferenced, for example, when testing an RCU-protected index against
+ * -1. Although rcu_access_index() may also be used in cases where
+ * update-side locks prevent the value of the index from changing, you
+ * should instead use rcu_dereference_index_protected() for this use case.
+ */
+#define rcu_access_index(p) __rcu_access_index((p), __rcu)
+
+/**
* rcu_dereference_index_check() - rcu_dereference for indices with debug checking
* @p: The pointer to read, prior to dereferencing
* @c: The conditions under which the dereference will take place