Commit f607c668 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

lockdep: Introduce lockdep_assert_held() 



Add a lockdep helper to validate that we indeed are the owner
of a lock.

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 98c33edd

include/linux/lockdep.h

+8 −0
Original line number Diff line number Diff line
@@ -296,6 +296,10 @@ extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass, 
extern void lock_release(struct lockdep_map *lock, int nested,

			 unsigned long ip);



#define lockdep_is_held(lock)	lock_is_held(&(lock)->dep_map)



extern int lock_is_held(struct lockdep_map *lock);



extern void lock_set_class(struct lockdep_map *lock, const char *name,

			   struct lock_class_key *key, unsigned int subclass,

			   unsigned long ip);
@@ -314,6 +318,8 @@ extern void lockdep_trace_alloc(gfp_t mask); 


#define lockdep_depth(tsk)	(debug_locks ? (tsk)->lockdep_depth : 0)



#define lockdep_assert_held(l)	WARN_ON(debug_locks && !lockdep_is_held(l))



#else /* !LOCKDEP */



static inline void lockdep_off(void)
@@ -358,6 +364,8 @@ struct lock_class_key { }; 


#define lockdep_depth(tsk)	(0)



#define lockdep_assert_held(l)			do { } while (0)



#endif /* !LOCKDEP */



#ifdef CONFIG_LOCK_STAT

kernel/lockdep.c

+33 −0
Original line number Diff line number Diff line
@@ -3059,6 +3059,19 @@ __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) 
	check_chain_key(curr);

}



static int __lock_is_held(struct lockdep_map *lock)

{

	struct task_struct *curr = current;

	int i;



	for (i = 0; i < curr->lockdep_depth; i++) {

		if (curr->held_locks[i].instance == lock)

			return 1;

	}



	return 0;

}



/*

 * Check whether we follow the irq-flags state precisely:

 */
@@ -3160,6 +3173,26 @@ void lock_release(struct lockdep_map *lock, int nested, 
}

EXPORT_SYMBOL_GPL(lock_release);



int lock_is_held(struct lockdep_map *lock)

{

	unsigned long flags;

	int ret = 0;



	if (unlikely(current->lockdep_recursion))

		return ret;



	raw_local_irq_save(flags);

	check_flags(flags);



	current->lockdep_recursion = 1;

	ret = __lock_is_held(lock);

	current->lockdep_recursion = 0;

	raw_local_irq_restore(flags);



	return ret;

}

EXPORT_SYMBOL_GPL(lock_is_held);



void lockdep_set_current_reclaim_state(gfp_t gfp_mask)

{

	current->lockdep_reclaim_gfp = gfp_mask;

kernel/sched.c

+2 −0
Original line number Diff line number Diff line
@@ -6609,6 +6609,8 @@ int cond_resched_lock(spinlock_t *lock) 
	int resched = should_resched();

	int ret = 0;



	lockdep_assert_held(lock);



	if (spin_needbreak(lock) || resched) {

		spin_unlock(lock);

		if (resched)