locking/lockdep: Split lockdep_free_key_range() and lockdep_reset_lock()

This patch does not change the behavior of these functions but makes the
patch that frees unused lock classes easier to read.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: johannes.berg@intel.com
Cc: tj@kernel.org
Link: https://lkml.kernel.org/r/20190214230058.196511-9-bvanassche@acm.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

kernel/locking/lockdep.c

@@ -4160,6 +4160,24 @@ static inline int within(const void *addr, void *start, unsigned long size)
 	return addr >= start && addr < start + size;
 }
 
+static void __lockdep_free_key_range(void *start, unsigned long size)
+{
+	struct lock_class *class;
+	struct hlist_head *head;
+	int i;
+
+	/* Unhash all classes that were created by a module. */
+	for (i = 0; i < CLASSHASH_SIZE; i++) {
+		head = classhash_table + i;
+		hlist_for_each_entry_rcu(class, head, hash_entry) {
+			if (!within(class->key, start, size) &&
+			    !within(class->name, start, size))
+				continue;
+			zap_class(class);
+		}
+	}
+}
+
 /*
  * Used in module.c to remove lock classes from memory that is going to be
  * freed; and possibly re-used by other modules.
@@ -4170,30 +4188,14 @@ static inline int within(const void *addr, void *start, unsigned long size)
  */
 void lockdep_free_key_range(void *start, unsigned long size)
 {
-	struct lock_class *class;
-	struct hlist_head *head;
 	unsigned long flags;
-	int i;
 	int locked;
 
 	init_data_structures_once();
 
 	raw_local_irq_save(flags);
 	locked = graph_lock();
-
-	/*
-	 * Unhash all classes that were created by this module:
-	 */
-	for (i = 0; i < CLASSHASH_SIZE; i++) {
-		head = classhash_table + i;
-		hlist_for_each_entry_rcu(class, head, hash_entry) {
-			if (within(class->key, start, size))
-				zap_class(class);
-			else if (within(class->name, start, size))
-				zap_class(class);
-		}
-	}
-
+	__lockdep_free_key_range(start, size);
 	if (locked)
 		graph_unlock();
 	raw_local_irq_restore(flags);
@@ -4235,16 +4237,11 @@ static bool lock_class_cache_is_registered(struct lockdep_map *lock)
 	return false;
 }
 
-void lockdep_reset_lock(struct lockdep_map *lock)
+/* The caller must hold the graph lock. Does not sleep. */
+static void __lockdep_reset_lock(struct lockdep_map *lock)
 {
 	struct lock_class *class;
-	unsigned long flags;
-	int j, locked;
-
-	init_data_structures_once();
-
-	raw_local_irq_save(flags);
-	locked = graph_lock();
+	int j;
 
 	/*
 	 * Remove all classes this lock might have:
@@ -4261,19 +4258,22 @@ void lockdep_reset_lock(struct lockdep_map *lock)
 	 * Debug check: in the end all mapped classes should
 	 * be gone.
 	 */
-	if (unlikely(lock_class_cache_is_registered(lock))) {
-		if (debug_locks_off_graph_unlock()) {
-			/*
-			 * We all just reset everything, how did it match?
-			 */
-			WARN_ON(1);
-		}
-		goto out_restore;
-	}
+	if (WARN_ON_ONCE(lock_class_cache_is_registered(lock)))
+		debug_locks_off();
+}
+
+void lockdep_reset_lock(struct lockdep_map *lock)
+{
+	unsigned long flags;
+	int locked;
+
+	init_data_structures_once();
+
+	raw_local_irq_save(flags);
+	locked = graph_lock();
+	__lockdep_reset_lock(lock);
 	if (locked)
 		graph_unlock();
-
-out_restore:
 	raw_local_irq_restore(flags);
 }