block: fix comment and add lockdep assert

After commit b89f625 ("block: don't release queue's sysfs lock during switching elevator"), whole elevator register and unregister function are covered by sysfs_lock. So, remove wrong comment and add lockdep assert. Signed-off-by: Yufen Yu <[email protected]> Signed-off-by: Jens Axboe <[email protected]>
vieko · Oct 9, 2020 · f0c6ae0 · f0c6ae0
1 parent 0841031
commit f0c6ae0
Showing 1 changed file with 4 additions and 10 deletions.
diff --git a/block/elevator.c b/block/elevator.c
@@ -479,16 +479,13 @@ static struct kobj_type elv_ktype = {
 	.release	= elevator_release,
 };
 
-/*
- * elv_register_queue is called from either blk_register_queue or
- * elevator_switch, elevator switch is prevented from being happen
- * in the two paths, so it is safe to not hold q->sysfs_lock.
- */
 int elv_register_queue(struct request_queue *q, bool uevent)
 {
 	struct elevator_queue *e = q->elevator;
 	int error;
 
+	lockdep_assert_held(&q->sysfs_lock);
+
 	error = kobject_add(&e->kobj, &q->kobj, "%s", "iosched");
 	if (!error) {
 		struct elv_fs_entry *attr = e->type->elevator_attrs;
@@ -507,13 +504,10 @@ int elv_register_queue(struct request_queue *q, bool uevent)
 	return error;
 }
 
-/*
- * elv_unregister_queue is called from either blk_unregister_queue or
- * elevator_switch, elevator switch is prevented from being happen
- * in the two paths, so it is safe to not hold q->sysfs_lock.
- */
 void elv_unregister_queue(struct request_queue *q)
 {
+	lockdep_assert_held(&q->sysfs_lock);
+
 	if (q) {
 		struct elevator_queue *e = q->elevator;