ANDROID: vendor_hook: Avoid clearing protect-flag before waking waiters

With hooks below, we can mark a lock-owned thread with an identifiable flag, which can protect it from being preempted by some other unimportant threads, and then waiter will be wakeup more quickly.
https://android-review.googlesource.com/c/kernel/common/+/2183353

but now we find an issue like this one:
static inline void __up_write(struct rw_semaphore *sem)
{
        ...
        // Step 1. we clear flag.
        trace_android_vh_record_rwsem_lock_starttime(current, 0);
        // Step 2. owner may be preempted by unimportant threads.
        rwsem_clear_owner(sem);
        ...
        // Step 3. wake up waiter, but it's too later.
        if (unlikely(tmp & RWSEM_FLAG_WAITERS))
                rwsem_wake(sem);
}

This patch will clear protect-flag after waking up waiters.

Bug: 286024926
Change-Id: I71f8b6a7d8a01336fd36b8267c2cb5edab65bd11
Signed-off-by: xieliujie <xieliujie@oppo.com>

include/linux/percpu-rwsem.h

@@ -109,7 +109,6 @@ static inline bool percpu_down_read_trylock(struct percpu_rw_semaphore *sem)
 
 static inline void percpu_up_read(struct percpu_rw_semaphore *sem)
 {
-	_trace_android_vh_record_pcpu_rwsem_starttime(current, 0);
 	rwsem_release(&sem->dep_map, _RET_IP_);
 
 	preempt_disable();
@@ -132,6 +131,7 @@ static inline void percpu_up_read(struct percpu_rw_semaphore *sem)
 		this_cpu_dec(*sem->read_count);
 		rcuwait_wake_up(&sem->writer);
 	}
+	_trace_android_vh_record_pcpu_rwsem_starttime(current, 0);
 	preempt_enable();
 }
 

kernel/locking/mutex.c

@@ -547,12 +547,12 @@ static noinline void __sched __mutex_unlock_slowpath(struct mutex *lock, unsigne
  */
 void __sched mutex_unlock(struct mutex *lock)
 {
-	trace_android_vh_record_mutex_lock_starttime(current, 0);
 #ifndef CONFIG_DEBUG_LOCK_ALLOC
 	if (__mutex_unlock_fast(lock))
 		return;
 #endif
 	__mutex_unlock_slowpath(lock, _RET_IP_);
+	trace_android_vh_record_mutex_lock_starttime(current, 0);
 }
 EXPORT_SYMBOL(mutex_unlock);
 

kernel/locking/percpu-rwsem.c

@@ -259,7 +259,6 @@ EXPORT_SYMBOL_GPL(percpu_down_write);
 
 void percpu_up_write(struct percpu_rw_semaphore *sem)
 {
-	trace_android_vh_record_pcpu_rwsem_starttime(current, 0);
 	rwsem_release(&sem->dep_map, _RET_IP_);
 
 	/*
@@ -285,6 +284,7 @@ void percpu_up_write(struct percpu_rw_semaphore *sem)
 	 * exclusive write lock because its counting.
 	 */
 	rcu_sync_exit(&sem->rss);
+	trace_android_vh_record_pcpu_rwsem_starttime(current, 0);
 }
 EXPORT_SYMBOL_GPL(percpu_up_write);
 

kernel/locking/rwsem.c

@@ -1367,7 +1367,6 @@ static inline void __up_read(struct rw_semaphore *sem)
 	DEBUG_RWSEMS_WARN_ON(sem->magic != sem, sem);
 	DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem);
 
-	trace_android_vh_record_rwsem_lock_starttime(current, 0);
 	preempt_disable();
 	rwsem_clear_reader_owned(sem);
 	tmp = atomic_long_add_return_release(-RWSEM_READER_BIAS, &sem->count);
@@ -1377,6 +1376,7 @@ static inline void __up_read(struct rw_semaphore *sem)
 		clear_nonspinnable(sem);
 		rwsem_wake(sem);
 	}
+	trace_android_vh_record_rwsem_lock_starttime(current, 0);
 	preempt_enable();
 }
 
@@ -1395,13 +1395,13 @@ static inline void __up_write(struct rw_semaphore *sem)
 	DEBUG_RWSEMS_WARN_ON((rwsem_owner(sem) != current) &&
 			    !rwsem_test_oflags(sem, RWSEM_NONSPINNABLE), sem);
 
-	trace_android_vh_record_rwsem_lock_starttime(current, 0);
 	preempt_disable();
 	rwsem_clear_owner(sem);
 	tmp = atomic_long_fetch_add_release(-RWSEM_WRITER_LOCKED, &sem->count);
 	preempt_enable();
 	if (unlikely(tmp & RWSEM_FLAG_WAITERS))
 		rwsem_wake(sem);
+	trace_android_vh_record_rwsem_lock_starttime(current, 0);
 }
 
 /*