Commit bc2dd71b authored by Boqun Feng's avatar Boqun Feng Committed by Peter Zijlstra
Browse files

locking/lockdep: Add a skip() function to __bfs() 



Some __bfs() walks will have additional iteration constraints (beyond
the path being strong). Provide an additional function to allow
terminating graph walks.

Signed-off-by: default avatarBoqun Feng <boqun.feng@gmail.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
parent dfd5e3f5

kernel/locking/lockdep.c

+19 −10
Original line number Diff line number Diff line
@@ -1672,6 +1672,7 @@ static inline struct lock_list *__bfs_next(struct lock_list *lock, int offset) 
static enum bfs_result __bfs(struct lock_list *source_entry,

			     void *data,

			     bool (*match)(struct lock_list *entry, void *data),

			     bool (*skip)(struct lock_list *entry, void *data),

			     struct lock_list **target_entry,

			     int offset)

{
@@ -1732,7 +1733,12 @@ static enum bfs_result __bfs(struct lock_list *source_entry, 
		/*

		 * Step 3: we haven't visited this and there is a strong

		 *         dependency path to this, so check with @match.

		 *         If @skip is provide and returns true, we skip this

		 *         lock (and any path this lock is in).

		 */

		if (skip && skip(lock, data))

			continue;



		if (match(lock, data)) {

			*target_entry = lock;

			return BFS_RMATCH;
@@ -1775,9 +1781,10 @@ static inline enum bfs_result 
__bfs_forwards(struct lock_list *src_entry,

	       void *data,

	       bool (*match)(struct lock_list *entry, void *data),

	       bool (*skip)(struct lock_list *entry, void *data),

	       struct lock_list **target_entry)

{

	return __bfs(src_entry, data, match, target_entry,

	return __bfs(src_entry, data, match, skip, target_entry,

		     offsetof(struct lock_class, locks_after));



}
@@ -1786,9 +1793,10 @@ static inline enum bfs_result 
__bfs_backwards(struct lock_list *src_entry,

		void *data,

		bool (*match)(struct lock_list *entry, void *data),

	       bool (*skip)(struct lock_list *entry, void *data),

		struct lock_list **target_entry)

{

	return __bfs(src_entry, data, match, target_entry,

	return __bfs(src_entry, data, match, skip, target_entry,

		     offsetof(struct lock_class, locks_before));



}
@@ -2019,7 +2027,7 @@ static unsigned long __lockdep_count_forward_deps(struct lock_list *this) 
	unsigned long  count = 0;

	struct lock_list *target_entry;



	__bfs_forwards(this, (void *)&count, noop_count, &target_entry);

	__bfs_forwards(this, (void *)&count, noop_count, NULL, &target_entry);



	return count;

}
@@ -2044,7 +2052,7 @@ static unsigned long __lockdep_count_backward_deps(struct lock_list *this) 
	unsigned long  count = 0;

	struct lock_list *target_entry;



	__bfs_backwards(this, (void *)&count, noop_count, &target_entry);

	__bfs_backwards(this, (void *)&count, noop_count, NULL, &target_entry);



	return count;

}
@@ -2072,11 +2080,12 @@ unsigned long lockdep_count_backward_deps(struct lock_class *class) 
static noinline enum bfs_result

check_path(struct held_lock *target, struct lock_list *src_entry,

	   bool (*match)(struct lock_list *entry, void *data),

	   bool (*skip)(struct lock_list *entry, void *data),

	   struct lock_list **target_entry)

{

	enum bfs_result ret;



	ret = __bfs_forwards(src_entry, target, match, target_entry);

	ret = __bfs_forwards(src_entry, target, match, skip, target_entry);



	if (unlikely(bfs_error(ret)))

		print_bfs_bug(ret);
@@ -2103,7 +2112,7 @@ check_noncircular(struct held_lock *src, struct held_lock *target, 


	debug_atomic_inc(nr_cyclic_checks);



	ret = check_path(target, &src_entry, hlock_conflict, &target_entry);

	ret = check_path(target, &src_entry, hlock_conflict, NULL, &target_entry);



	if (unlikely(ret == BFS_RMATCH)) {

		if (!*trace) {
@@ -2152,7 +2161,7 @@ check_redundant(struct held_lock *src, struct held_lock *target) 


	debug_atomic_inc(nr_redundant_checks);



	ret = check_path(target, &src_entry, hlock_equal, &target_entry);

	ret = check_path(target, &src_entry, hlock_equal, NULL, &target_entry);



	if (ret == BFS_RMATCH)

		debug_atomic_inc(nr_redundant);
@@ -2246,7 +2255,7 @@ find_usage_forwards(struct lock_list *root, unsigned long usage_mask, 


	debug_atomic_inc(nr_find_usage_forwards_checks);



	result = __bfs_forwards(root, &usage_mask, usage_match, target_entry);

	result = __bfs_forwards(root, &usage_mask, usage_match, NULL, target_entry);



	return result;

}
@@ -2263,7 +2272,7 @@ find_usage_backwards(struct lock_list *root, unsigned long usage_mask, 


	debug_atomic_inc(nr_find_usage_backwards_checks);



	result = __bfs_backwards(root, &usage_mask, usage_match, target_entry);

	result = __bfs_backwards(root, &usage_mask, usage_match, NULL, target_entry);



	return result;

}
@@ -2628,7 +2637,7 @@ static int check_irq_usage(struct task_struct *curr, struct held_lock *prev, 
	 */

	bfs_init_rootb(&this, prev);



	ret = __bfs_backwards(&this, &usage_mask, usage_accumulate, NULL);

	ret = __bfs_backwards(&this, &usage_mask, usage_accumulate, NULL, NULL);

	if (bfs_error(ret)) {

		print_bfs_bug(ret);

		return 0;