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Commit 2904d9fa authored by Bart Van Assche's avatar Bart Van Assche Committed by Ingo Molnar
Browse files

locking/lockdep: Introduce lock_class_cache_is_registered() 



This patch does not change any functionality but makes the
lockdep_reset_lock() function easier to read.

Signed-off-by: default avatarBart Van Assche <bvanassche@acm.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <longman@redhat.com>
Cc: johannes.berg@intel.com
Cc: tj@kernel.org
Link: https://lkml.kernel.org/r/20181207011148.251812-11-bvanassche@acm.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent d35568bd

kernel/locking/lockdep.c

+30 −20
Original line number Diff line number Diff line
@@ -4201,13 +4201,33 @@ void lockdep_free_key_range(void *start, unsigned long size) 
	 */

}



void lockdep_reset_lock(struct lockdep_map *lock)

/*

 * Check whether any element of the @lock->class_cache[] array refers to a

 * registered lock class. The caller must hold either the graph lock or the

 * RCU read lock.

 */

static bool lock_class_cache_is_registered(struct lockdep_map *lock)

{

	struct lock_class *class;

	struct hlist_head *head;

	unsigned long flags;

	int i, j;

	int locked;



	for (i = 0; i < CLASSHASH_SIZE; i++) {

		head = classhash_table + i;

		hlist_for_each_entry_rcu(class, head, hash_entry) {

			for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++)

				if (lock->class_cache[j] == class)

					return true;

		}

	}

	return false;

}



void lockdep_reset_lock(struct lockdep_map *lock)

{

	struct lock_class *class;

	unsigned long flags;

	int j, locked;



	raw_local_irq_save(flags);
@@ -4227,15 +4247,7 @@ void lockdep_reset_lock(struct lockdep_map *lock) 
	 * be gone.

	 */

	locked = graph_lock();

	for (i = 0; i < CLASSHASH_SIZE; i++) {

		head = classhash_table + i;

		hlist_for_each_entry_rcu(class, head, hash_entry) {

			int match = 0;



			for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++)

				match |= class == lock->class_cache[j];



			if (unlikely(match)) {

	if (unlikely(lock_class_cache_is_registered(lock))) {

		if (debug_locks_off_graph_unlock()) {

			/*

			 * We all just reset everything, how did it match?
@@ -4244,8 +4256,6 @@ void lockdep_reset_lock(struct lockdep_map *lock) 
		}

		goto out_restore;

	}

		}

	}

	if (locked)

		graph_unlock();