From 4c907baf36d8339f393bb576d0bab29194d0e6ad Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Tue, 6 Jan 2015 10:26:10 -0500 Subject: percpu_ref: implement percpu_ref_is_dying() 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 Cc: Kent Overstreet --- include/linux/percpu-refcount.h | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'include/linux/percpu-refcount.h') diff --git a/include/linux/percpu-refcount.h b/include/linux/percpu-refcount.h index 6a7a670366ab..12c9b485beb7 100644 --- a/include/linux/percpu-refcount.h +++ b/include/linux/percpu-refcount.h @@ -294,6 +294,20 @@ static inline void percpu_ref_put(struct percpu_ref *ref) percpu_ref_put_many(ref, 1); } +/** + * 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 -- cgit v1.2.3-59-g8ed1b