percpu_ref: rename things to prepare for decoupling percpu/atomic mode switch
percpu_ref will be restructured so that percpu/atomic mode switching
and reference killing are dedoupled. In preparation, do the following
renames.
* percpu_ref->confirm_kill -> percpu_ref->confirm_switch
* __PERCPU_REF_DEAD -> __PERCPU_REF_ATOMIC
* __percpu_ref_alive() -> __ref_is_percpu()
This patch is pure rename and doesn't introduce any functional
changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Kent Overstreet <kmo@daterainc.com>
diff --git a/include/linux/percpu-refcount.h b/include/linux/percpu-refcount.h
index 3d463a3..910e5f7 100644
--- a/include/linux/percpu-refcount.h
+++ b/include/linux/percpu-refcount.h
@@ -54,6 +54,11 @@
struct percpu_ref;
typedef void (percpu_ref_func_t)(struct percpu_ref *);
+/* flags set in the lower bits of percpu_ref->percpu_count_ptr */
+enum {
+ __PERCPU_REF_ATOMIC = 1LU << 0, /* operating in atomic mode */
+};
+
struct percpu_ref {
atomic_long_t count;
/*
@@ -62,7 +67,7 @@
*/
unsigned long percpu_count_ptr;
percpu_ref_func_t *release;
- percpu_ref_func_t *confirm_kill;
+ percpu_ref_func_t *confirm_switch;
struct rcu_head rcu;
};
@@ -88,23 +93,21 @@
return percpu_ref_kill_and_confirm(ref, NULL);
}
-#define __PERCPU_REF_DEAD 1
-
/*
* Internal helper. Don't use outside percpu-refcount proper. The
* function doesn't return the pointer and let the caller test it for NULL
* because doing so forces the compiler to generate two conditional
* branches as it can't assume that @ref->percpu_count is not NULL.
*/
-static inline bool __percpu_ref_alive(struct percpu_ref *ref,
- unsigned long __percpu **percpu_countp)
+static inline bool __ref_is_percpu(struct percpu_ref *ref,
+ unsigned long __percpu **percpu_countp)
{
unsigned long percpu_ptr = ACCESS_ONCE(ref->percpu_count_ptr);
/* paired with smp_store_release() in percpu_ref_reinit() */
smp_read_barrier_depends();
- if (unlikely(percpu_ptr & __PERCPU_REF_DEAD))
+ if (unlikely(percpu_ptr & __PERCPU_REF_ATOMIC))
return false;
*percpu_countp = (unsigned long __percpu *)percpu_ptr;
@@ -125,7 +128,7 @@
rcu_read_lock_sched();
- if (__percpu_ref_alive(ref, &percpu_count))
+ if (__ref_is_percpu(ref, &percpu_count))
this_cpu_inc(*percpu_count);
else
atomic_long_inc(&ref->count);
@@ -149,7 +152,7 @@
rcu_read_lock_sched();
- if (__percpu_ref_alive(ref, &percpu_count)) {
+ if (__ref_is_percpu(ref, &percpu_count)) {
this_cpu_inc(*percpu_count);
ret = true;
} else {
@@ -183,7 +186,7 @@
rcu_read_lock_sched();
- if (__percpu_ref_alive(ref, &percpu_count)) {
+ if (__ref_is_percpu(ref, &percpu_count)) {
this_cpu_inc(*percpu_count);
ret = true;
}
@@ -208,7 +211,7 @@
rcu_read_lock_sched();
- if (__percpu_ref_alive(ref, &percpu_count))
+ if (__ref_is_percpu(ref, &percpu_count))
this_cpu_dec(*percpu_count);
else if (unlikely(atomic_long_dec_and_test(&ref->count)))
ref->release(ref);
@@ -228,7 +231,7 @@
{
unsigned long __percpu *percpu_count;
- if (__percpu_ref_alive(ref, &percpu_count))
+ if (__ref_is_percpu(ref, &percpu_count))
return false;
return !atomic_long_read(&ref->count);
}