[PATCH 3.16 219/370] jump_labels: API for flushing deferred jump label updates

Ben Hutchings
2017-03-10T12:18:03Z

From: David Matlack <dmatlack@google.com>

commit b6416e61012429e0277bd15a229222fd17afc1c1 upstream.

Modules that use static_key_deferred need a way to synchronize with
any delayed work that is still pending when the module is unloaded.
Introduce static_key_deferred_flush() which flushes any pending
jump label updates.

Signed-off-by: David Matlack <dmatlack@google.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
include/linux/jump_label_ratelimit.h | 5 +++++
kernel/jump_label.c | 7 +++++++
2 files changed, 12 insertions(+)

--- a/include/linux/jump_label_ratelimit.h
+++ b/include/linux/jump_label_ratelimit.h
@@ -14,6 +14,7 @@ struct static_key_deferred {

#ifdef HAVE_JUMP_LABEL
extern void static_key_slow_dec_deferred(struct static_key_deferred *key);
+extern void static_key_deferred_flush(struct static_key_deferred *key);
extern void
jump_label_rate_limit(struct static_key_deferred *key, unsigned long rl);

@@ -26,6 +27,10 @@ static inline void static_key_slow_dec_d
STATIC_KEY_CHECK_USE();
static_key_slow_dec(&key->key);
}
+static inline void static_key_deferred_flush(struct static_key_deferred *key)
+{
+ STATIC_KEY_CHECK_USE();
+}
static inline void
jump_label_rate_limit(struct static_key_deferred *key,
unsigned long rl)
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -116,6 +116,13 @@ void static_key_slow_dec_deferred(struct
}
EXPORT_SYMBOL_GPL(static_key_slow_dec_deferred);

+void static_key_deferred_flush(struct static_key_deferred *key)
+{
+ STATIC_KEY_CHECK_USE();
+ flush_delayed_work(&key->work);
+}
+EXPORT_SYMBOL_GPL(static_key_deferred_flush);
+
void jump_label_rate_limit(struct static_key_deferred *key,
unsigned long rl)
{