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>
diff --git a/lib/percpu-refcount.c b/lib/percpu-refcount.c
index 070dab5..8ef3f5c 100644
--- a/lib/percpu-refcount.c
+++ b/lib/percpu-refcount.c
@@ -108,7 +108,6 @@
* 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 @@
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 @@
* 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 @@
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 @@
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);