percpu_ref: minor code and comment updates

* Some comments became stale.  Updated.
* percpu_ref_tryget() unnecessarily initializes @ret.  Removed.
* A blank line removed from percpu_ref_kill_rcu().
* Explicit function name in a WARN format string replaced with __func__.
* WARN_ON() in percpu_ref_reinit() converted to WARN_ON_ONCE().

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Kent Overstreet <kmo@daterainc.com>

1 files changed, 6 insertions, 8 deletions

diff --git a/lib/percpu-refcount.c b/lib/percpu-refcount.c
index 070dab5e7d77..8ef3f5c20df6 100644
--- a/lib/percpu-refcount.c
+++ b/lib/percpu-refcount.c
@@ -108,7 +108,6 @@ static void percpu_ref_kill_rcu(struct rcu_head *rcu)
          * reaching 0 before we add the percpu counts. But doing it at the same
          * time is equivalent and saves us atomic operations:
          */
-
         atomic_long_add((long)count - PCPU_COUNT_BIAS, &ref->count);
 
         WARN_ONCE(atomic_long_read(&ref->count) <= 0,
@@ -120,8 +119,8 @@ static void percpu_ref_kill_rcu(struct rcu_head *rcu)
                 ref->confirm_kill(ref);
 
         /*
-         * Now we're in single atomic_t mode with a consistent refcount, so it's
-         * safe to drop our initial ref:
+         * Now we're in single atomic_long_t mode with a consistent
+         * refcount, so it's safe to drop our initial ref:
          */
         percpu_ref_put(ref);
 }
@@ -134,8 +133,8 @@ static void percpu_ref_kill_rcu(struct rcu_head *rcu)
  * Equivalent to percpu_ref_kill() but also schedules kill confirmation if
  * @confirm_kill is not NULL.  @confirm_kill, which may not block, will be
  * called after @ref is seen as dead from all CPUs - all further
- * invocations of percpu_ref_tryget() will fail.  See percpu_ref_tryget()
- * for more details.
+ * invocations of percpu_ref_tryget_live() will fail.  See
+ * percpu_ref_tryget_live() for more details.
  *
  * Due to the way percpu_ref is implemented, @confirm_kill will be called
  * after at least one full RCU grace period has passed but this is an
@@ -145,8 +144,7 @@ void percpu_ref_kill_and_confirm(struct percpu_ref *ref,
                                  percpu_ref_func_t *confirm_kill)
 {
         WARN_ONCE(ref->pcpu_count_ptr & PCPU_REF_DEAD,
-                  "percpu_ref_kill() called more than once on %pf!",
-                  ref->release);
+                  "%s called more than once on %pf!", __func__, ref->release);
 
         ref->pcpu_count_ptr |= PCPU_REF_DEAD;
         ref->confirm_kill = confirm_kill;
@@ -172,7 +170,7 @@ void percpu_ref_reinit(struct percpu_ref *ref)
         int cpu;
 
         BUG_ON(!pcpu_count);
-        WARN_ON(!percpu_ref_is_zero(ref));
+        WARN_ON_ONCE(!percpu_ref_is_zero(ref));
 
         atomic_long_set(&ref->count, 1 + PCPU_COUNT_BIAS);