...and update its comment to explicitly reference its association with
mmu_notifier_call_srcu().
Contrary to its name, mmu_notifier_synchronize() does not synchronize
the notifier's SRCU instance, but rather waits for RCU callbacks to
finished, i.e. it invokes rcu_barrier(). The RCU documentation is
quite clear on this matter, explicitly calling out that rcu_barrier()
does not imply synchronize_rcu(). The misnomer could lean an unwary
developer to incorrectly assume that mmu_notifier_synchronize() can
be used in conjunction with mmu_notifier_unregister_no_release() to
implement a variation of mmu_notifier_unregister() that synchronizes
SRCU without invoking ->release. A Documentation-allergic and hasty
developer could be further confused by the fact that rcu_barrier() is
indeed a pass-through to synchronize_rcu()... in tiny SRCU.
Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
---
mm/mmu_notifier.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c
index 5119ff846769..46ebea6483bf 100644
--- a/mm/mmu_notifier.c
+++ b/mm/mmu_notifier.c
@@ -35,12 +35,12 @@ void mmu_notifier_call_srcu(struct rcu_head *rcu,
}
EXPORT_SYMBOL_GPL(mmu_notifier_call_srcu);
-void mmu_notifier_synchronize(void)
+void mmu_notifier_barrier(void)
{
- /* Wait for any running method to finish. */
+ /* Wait for any running RCU callbacks (see above) to finish. */
srcu_barrier(&srcu);
}
-EXPORT_SYMBOL_GPL(mmu_notifier_synchronize);
+EXPORT_SYMBOL_GPL(mmu_notifier_barrier);
/*
* This function can't run concurrently against mmu_notifier_register
--
2.19.1
