From 9a1049da9bd2cd83fe11d46433e603c193aa9c71 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Sat, 28 Jun 2014 08:10:14 -0400 Subject: percpu-refcount: require percpu_ref to be exited explicitly Currently, a percpu_ref undoes percpu_ref_init() automatically by freeing the allocated percpu area when the percpu_ref is killed. While seemingly convenient, this has the following niggles. * It's impossible to re-init a released reference counter without going through re-allocation. * In the similar vein, it's impossible to initialize a percpu_ref count with static percpu variables. * We need and have an explicit destructor anyway for failure paths - percpu_ref_cancel_init(). This patch removes the automatic percpu counter freeing in percpu_ref_kill_rcu() and repurposes percpu_ref_cancel_init() into a generic destructor now named percpu_ref_exit(). percpu_ref_destroy() is considered but it gets confusing with percpu_ref_kill() while "exit" clearly indicates that it's the counterpart of percpu_ref_init(). All percpu_ref_cancel_init() users are updated to invoke percpu_ref_exit() instead and explicit percpu_ref_exit() calls are added to the destruction path of all percpu_ref users. Signed-off-by: Tejun Heo Acked-by: Benjamin LaHaise Cc: Kent Overstreet Cc: Christoph Lameter Cc: Benjamin LaHaise Cc: Nicholas A. Bellinger Cc: Li Zefan --- include/linux/percpu-refcount.h | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'include/linux/percpu-refcount.h') diff --git a/include/linux/percpu-refcount.h b/include/linux/percpu-refcount.h index 6f8cd4c0546c..0ddd2839ca84 100644 --- a/include/linux/percpu-refcount.h +++ b/include/linux/percpu-refcount.h @@ -57,9 +57,7 @@ struct percpu_ref { atomic_t count; /* * The low bit of the pointer indicates whether the ref is in percpu - * mode; if set, then get/put will manipulate the atomic_t (this is a - * hack because we need to keep the pointer around for - * percpu_ref_kill_rcu()) + * mode; if set, then get/put will manipulate the atomic_t. */ unsigned long pcpu_count_ptr; percpu_ref_func_t *release; @@ -69,7 +67,7 @@ struct percpu_ref { int __must_check percpu_ref_init(struct percpu_ref *ref, percpu_ref_func_t *release); -void percpu_ref_cancel_init(struct percpu_ref *ref); +void percpu_ref_exit(struct percpu_ref *ref); void percpu_ref_kill_and_confirm(struct percpu_ref *ref, percpu_ref_func_t *confirm_kill); -- cgit