The cmpxcgh() was just to ensure the debug check didn't race, which was
a bit excessive. The caller is supposed to do the appropriate
synchronization, which means percpu_ref_kill() can just do a simple
store.
Signed-off-by: Kent Overstreet <koverstr...@google.com>
---
lib/percpu-refcount.c | 19 ++++---------------
1 file changed, 4 insertions(+), 15 deletions(-)
diff --git a/lib/percpu-refcount.c b/lib/percpu-refcount.c
index e65820a..04be7ea 100644
--- a/lib/percpu-refcount.c
+++ b/lib/percpu-refcount.c
@@ -107,22 +107,11 @@ static void percpu_ref_kill_rcu(struct rcu_head *rcu)
*/
void percpu_ref_kill(struct percpu_ref *ref)
{
- unsigned __percpu *pcpu_count, *old, *new;
+ WARN_ONCE(REF_STATUS(ref->pcpu_count) == PCPU_REF_DEAD,
+ "percpu_ref_kill() called more than once!\n");
- pcpu_count = ACCESS_ONCE(ref->pcpu_count);
-
- do {
- if (REF_STATUS(pcpu_count) == PCPU_REF_DEAD) {
- WARN(1, "percpu_ref_kill() called more than once!\n");
- return;
- }
-
- old = pcpu_count;
- new = (unsigned __percpu *)
- (((unsigned long) pcpu_count)|PCPU_REF_DEAD);
-
- pcpu_count = cmpxchg(&ref->pcpu_count, old, new);
- } while (pcpu_count != old);
+ ref->pcpu_count = (unsigned __percpu *)
+ (((unsigned long) ref->pcpu_count)|PCPU_REF_DEAD);
call_rcu(&ref->rcu, percpu_ref_kill_rcu);
}
--
1.8.2.1
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