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>

1 files changed, 14 insertions, 11 deletions

diff --git a/include/linux/percpu-refcount.h b/include/linux/percpu-refcount.h
index 3d463a39e0f7..910e5f72055d 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 @@ struct percpu_ref {
          */
         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 @@ static inline void percpu_ref_kill(struct percpu_ref *ref)
         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 @@ static inline void percpu_ref_get(struct percpu_ref *ref)
 
         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 @@ static inline bool percpu_ref_tryget(struct percpu_ref *ref)
 
         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 @@ static inline bool percpu_ref_tryget_live(struct percpu_ref *ref)
 
         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 @@ static inline void percpu_ref_put(struct percpu_ref *ref)
 
         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 @@ static inline bool percpu_ref_is_zero(struct percpu_ref *ref)
 {
         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);
 }