lockdep: fixup mutex annotations
The fancy mutex_lock fastpath has too many indirections to track the caller
hence all contentions are perceived to come from mutex_lock().
Avoid this by explicitly not using the fastpath code (it was disabled already
anyway).
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/mutex.c b/kernel/mutex.c
index 691b865..d7fe50c 100644
--- a/kernel/mutex.c
+++ b/kernel/mutex.c
@@ -51,6 +51,7 @@
EXPORT_SYMBOL(__mutex_init);
+#ifndef CONFIG_DEBUG_LOCK_ALLOC
/*
* We split the mutex lock/unlock logic into separate fastpath and
* slowpath functions, to reduce the register pressure on the fastpath.
@@ -92,6 +93,7 @@
}
EXPORT_SYMBOL(mutex_lock);
+#endif
static void fastcall noinline __sched
__mutex_unlock_slowpath(atomic_t *lock_count);
@@ -122,7 +124,8 @@
* Lock a mutex (possibly interruptible), slowpath:
*/
static inline int __sched
-__mutex_lock_common(struct mutex *lock, long state, unsigned int subclass)
+__mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
+ unsigned long ip)
{
struct task_struct *task = current;
struct mutex_waiter waiter;
@@ -132,7 +135,7 @@
spin_lock_mutex(&lock->wait_lock, flags);
debug_mutex_lock_common(lock, &waiter);
- mutex_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
+ mutex_acquire(&lock->dep_map, subclass, 0, ip);
debug_mutex_add_waiter(lock, &waiter, task_thread_info(task));
/* add waiting tasks to the end of the waitqueue (FIFO): */
@@ -143,7 +146,7 @@
if (old_val == 1)
goto done;
- lock_contended(&lock->dep_map, _RET_IP_);
+ lock_contended(&lock->dep_map, ip);
for (;;) {
/*
@@ -166,7 +169,7 @@
if (unlikely(state == TASK_INTERRUPTIBLE &&
signal_pending(task))) {
mutex_remove_waiter(lock, &waiter, task_thread_info(task));
- mutex_release(&lock->dep_map, 1, _RET_IP_);
+ mutex_release(&lock->dep_map, 1, ip);
spin_unlock_mutex(&lock->wait_lock, flags);
debug_mutex_free_waiter(&waiter);
@@ -197,20 +200,12 @@
return 0;
}
-static void fastcall noinline __sched
-__mutex_lock_slowpath(atomic_t *lock_count)
-{
- struct mutex *lock = container_of(lock_count, struct mutex, count);
-
- __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0);
-}
-
#ifdef CONFIG_DEBUG_LOCK_ALLOC
void __sched
mutex_lock_nested(struct mutex *lock, unsigned int subclass)
{
might_sleep();
- __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, subclass);
+ __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, subclass, _RET_IP_);
}
EXPORT_SYMBOL_GPL(mutex_lock_nested);
@@ -219,7 +214,7 @@
mutex_lock_interruptible_nested(struct mutex *lock, unsigned int subclass)
{
might_sleep();
- return __mutex_lock_common(lock, TASK_INTERRUPTIBLE, subclass);
+ return __mutex_lock_common(lock, TASK_INTERRUPTIBLE, subclass, _RET_IP_);
}
EXPORT_SYMBOL_GPL(mutex_lock_interruptible_nested);
@@ -271,6 +266,7 @@
__mutex_unlock_common_slowpath(lock_count, 1);
}
+#ifndef CONFIG_DEBUG_LOCK_ALLOC
/*
* Here come the less common (and hence less performance-critical) APIs:
* mutex_lock_interruptible() and mutex_trylock().
@@ -298,13 +294,22 @@
EXPORT_SYMBOL(mutex_lock_interruptible);
+static void fastcall noinline __sched
+__mutex_lock_slowpath(atomic_t *lock_count)
+{
+ struct mutex *lock = container_of(lock_count, struct mutex, count);
+
+ __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0, _RET_IP_);
+}
+
static int fastcall noinline __sched
__mutex_lock_interruptible_slowpath(atomic_t *lock_count)
{
struct mutex *lock = container_of(lock_count, struct mutex, count);
- return __mutex_lock_common(lock, TASK_INTERRUPTIBLE, 0);
+ return __mutex_lock_common(lock, TASK_INTERRUPTIBLE, 0, _RET_IP_);
}
+#endif
/*
* Spinlock based trylock, we take the spinlock and check whether we