linux-kernel - [PATCH 24/27] locking/lockdep: Introduce __lockdep_free_key

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Date:   Wed, 28 Nov 2018 15:43:22 -0800
From:   Bart Van Assche <bvanassche@....org>
To:     mingo@...hat.com
Cc:     peterz@...radead.org, tj@...nel.org, johannes.berg@...el.com,
        linux-kernel@...r.kernel.org, Bart Van Assche <bvanassche@....org>
Subject: [PATCH 24/27] locking/lockdep: Introduce __lockdep_free_key_range()

This patch does not change any functionality but makes the next patch
in this series easier to read.

Signed-off-by: Bart Van Assche <bvanassche@....org>
---
 kernel/locking/lockdep.c | 35 +++++++++++++++++++++++------------
 1 file changed, 23 insertions(+), 12 deletions(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 141bb0662ff5..0e273731d028 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -4459,18 +4459,16 @@ static void free_zapped_classes(struct list_head *zapped_classes)
 }
 
 /*
- * Used in module.c to remove lock classes from memory that is going to be
- * freed; and possibly re-used by other modules.
- *
- * We will have had one sync_sched() before getting here, so we're guaranteed
- * nobody will look up these exact classes -- they're properly dead but still
- * allocated.
+ * Remove all lock classes from the class hash table and from the
+ * all_lock_classes list whose key or name is in the address range
+ * [start, start + size). Move these lock classes to the
+ * @zapped_classes list.
  */
-void lockdep_free_key_range(void *start, unsigned long size)
+static void __lockdep_free_key_range(struct list_head *zapped_classes,
+				     void *start, unsigned long size)
 {
 	struct lock_class *class;
 	struct hlist_head *head;
-	LIST_HEAD(zapped_classes);
 	unsigned long flags;
 	int i;
 	int locked;
@@ -4478,9 +4476,8 @@ void lockdep_free_key_range(void *start, unsigned long size)
 	raw_local_irq_save(flags);
 	locked = graph_lock();
 
-	/*
-	 * Unhash all classes that were created by this module:
-	 */
+	INIT_LIST_HEAD(zapped_classes);
+
 	for (i = 0; i < CLASSHASH_SIZE; i++) {
 		head = classhash_table + i;
 		hlist_for_each_entry_rcu(class, head, hash_entry) {
@@ -4488,14 +4485,28 @@ void lockdep_free_key_range(void *start, unsigned long size)
 			    (!within(class->key, start, size) &&
 			     !within(class->name, start, size)))
 				continue;
-			zap_class(&zapped_classes, class);
+			zap_class(zapped_classes, class);
 		}
 	}
 
 	if (locked)
 		graph_unlock();
 	raw_local_irq_restore(flags);
+}
+
+/*
+ * Used in module.c to remove lock classes from memory that is going to be
+ * freed; and possibly re-used by other modules.
+ *
+ * We will have had one sync_sched() before getting here, so we're guaranteed
+ * nobody will look up these exact classes -- they're properly dead but still
+ * allocated.
+ */
+void lockdep_free_key_range(void *start, unsigned long size)
+{
+	LIST_HEAD(zapped_classes);
 
+	__lockdep_free_key_range(&zapped_classes, start, size);
 	free_zapped_classes(&zapped_classes);
 }
 
-- 
2.20.0.rc0.387.gc7a69e6b6c-goog