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-rw-r--r--lib/percpu-refcount.c22
1 files changed, 4 insertions, 18 deletions
diff --git a/lib/percpu-refcount.c b/lib/percpu-refcount.c
index 27fe74948882..8ade009ca2c9 100644
--- a/lib/percpu-refcount.c
+++ b/lib/percpu-refcount.c
@@ -177,17 +177,11 @@ static void __percpu_ref_switch_to_atomic(struct percpu_ref *ref,
call_rcu_sched(&ref->rcu, percpu_ref_switch_to_atomic_rcu);
} else if (confirm_switch) {
/*
- * Somebody already set ATOMIC. Switching may still be in
- * progress. @confirm_switch must be invoked after the
- * switching is complete and a full sched RCU grace period
- * has passed. Wait synchronously for the previous
- * switching and schedule @confirm_switch invocation.
+ * Somebody else already set ATOMIC. Wait for its
+ * completion and invoke @confirm_switch() directly.
*/
wait_event(percpu_ref_switch_waitq, !ref->confirm_switch);
- ref->confirm_switch = confirm_switch;
-
- percpu_ref_get(ref); /* put after confirmation */
- call_rcu_sched(&ref->rcu, percpu_ref_call_confirm_rcu);
+ confirm_switch(ref);
}
}
@@ -211,10 +205,6 @@ static void __percpu_ref_switch_to_atomic(struct percpu_ref *ref,
* but it may block if @confirm_kill is specified and @ref is already in
* the process of switching to atomic mode. In such cases, @confirm_switch
* will be invoked after the switching is complete.
- *
- * Due to the way percpu_ref is implemented, @confirm_switch will be called
- * after at least one full sched RCU grace period has passed but this is an
- * implementation detail and must not be depended upon.
*/
void percpu_ref_switch_to_atomic(struct percpu_ref *ref,
percpu_ref_func_t *confirm_switch)
@@ -290,11 +280,7 @@ void percpu_ref_switch_to_percpu(struct percpu_ref *ref)
*
* This function normally doesn't block and can be called from any context
* but it may block if @confirm_kill is specified and @ref is in the
- * process of switching to atomic mode by percpu_ref_switch_atomic().
- *
- * Due to the way percpu_ref is implemented, @confirm_switch will be called
- * after at least one full sched RCU grace period has passed but this is an
- * implementation detail and must not be depended upon.
+ * process of switching to atomic mode by percpu_ref_switch_to_atomic().
*/
void percpu_ref_kill_and_confirm(struct percpu_ref *ref,
percpu_ref_func_t *confirm_kill)