Implement percpu_ref_is_dying() which tests whether the ref is dying
or dead. This is useful to determine the current state when a
percpu_ref is used as a cyclic on/off switch via kill and reinit.
Signed-off-by: Tejun Heo <t...@kernel.org>
Cc: Kent Overstreet <k...@daterainc.com>
---
Hello,
This will be used by the scheduled cgroup writeback support. I'm
applying these two to percpu/for-3.20.
Thanks.
include/linux/percpu-refcount.h | 14 ++++++++++++++
1 file changed, 14 insertions(+)
--- a/include/linux/percpu-refcount.h
+++ b/include/linux/percpu-refcount.h
@@ -295,6 +295,20 @@ static inline void percpu_ref_put(struct
}
/**
+ * percpu_ref_is_dying - test whether a percpu refcount is dying or dead
+ * @ref: percpu_ref to test
+ *
+ * Returns %true if @ref is dying or dead.
+ *
+ * This function is safe to call as long as @ref is between init and exit
+ * and the caller is responsible for synchronizing against state changes.
+ */
+static inline bool percpu_ref_is_dying(struct percpu_ref *ref)
+{
+ return ref->percpu_count_ptr & __PERCPU_REF_DEAD;
+}
+
+/**
* percpu_ref_is_zero - test whether a percpu refcount reached zero
* @ref: percpu_ref to test
*
--
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