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/include/linux/percpu-refcount.h b/include/linux/percpu-refcount.h
index f015f13..d44b027 100644
--- a/include/linux/percpu-refcount.h
+++ b/include/linux/percpu-refcount.h
@@ -115,8 +115,10 @@
* percpu_ref_get - increment a percpu refcount
* @ref: percpu_ref to get
*
- * Analagous to atomic_inc().
- */
+ * Analagous to atomic_long_inc().
+ *
+ * This function is safe to call as long as @ref is between init and exit.
+ */
static inline void percpu_ref_get(struct percpu_ref *ref)
{
unsigned long __percpu *pcpu_count;
@@ -138,12 +140,12 @@
* Increment a percpu refcount unless its count already reached zero.
* Returns %true on success; %false on failure.
*
- * The caller is responsible for ensuring that @ref stays accessible.
+ * This function is safe to call as long as @ref is between init and exit.
*/
static inline bool percpu_ref_tryget(struct percpu_ref *ref)
{
unsigned long __percpu *pcpu_count;
- int ret = false;
+ int ret;
rcu_read_lock_sched();
@@ -166,12 +168,13 @@
* Increment a percpu refcount unless it has already been killed. Returns
* %true on success; %false on failure.
*
- * Completion of percpu_ref_kill() in itself doesn't guarantee that tryget
- * will fail. For such guarantee, percpu_ref_kill_and_confirm() should be
- * used. After the confirm_kill callback is invoked, it's guaranteed that
- * no new reference will be given out by percpu_ref_tryget().
+ * Completion of percpu_ref_kill() in itself doesn't guarantee that this
+ * function will fail. For such guarantee, percpu_ref_kill_and_confirm()
+ * should be used. After the confirm_kill callback is invoked, it's
+ * guaranteed that no new reference will be given out by
+ * percpu_ref_tryget_live().
*
- * The caller is responsible for ensuring that @ref stays accessible.
+ * This function is safe to call as long as @ref is between init and exit.
*/
static inline bool percpu_ref_tryget_live(struct percpu_ref *ref)
{
@@ -196,6 +199,8 @@
*
* Decrement the refcount, and if 0, call the release function (which was passed
* to percpu_ref_init())
+ *
+ * This function is safe to call as long as @ref is between init and exit.
*/
static inline void percpu_ref_put(struct percpu_ref *ref)
{
@@ -216,6 +221,8 @@
* @ref: percpu_ref to test
*
* Returns %true if @ref reached zero.
+ *
+ * This function is safe to call as long as @ref is between init and exit.
*/
static inline bool percpu_ref_is_zero(struct percpu_ref *ref)
{