blk-mq: Let blk_mq_debugfs_register() look up the queue name

A later patch will move the call of blk_mq_debugfs_register() to
a function to which the queue name is not passed as an argument.
To avoid having to add a 'name' argument to multiple callers, let
blk_mq_debugfs_register() look up the queue name.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

block/blk-mq-debugfs.c

@@ -785,12 +785,13 @@ static const struct blk_mq_debugfs_attr blk_mq_debugfs_ctx_attrs[] = {
 	{},
 };
 
-int blk_mq_debugfs_register(struct request_queue *q, const char *name)
+int blk_mq_debugfs_register(struct request_queue *q)
 {
 	if (!blk_debugfs_root)
 		return -ENOENT;
 
-	q->debugfs_dir = debugfs_create_dir(name, blk_debugfs_root);
+	q->debugfs_dir = debugfs_create_dir(kobject_name(q->kobj.parent),
+					    blk_debugfs_root);
 	if (!q->debugfs_dir)
 		goto err;
 

block/blk-mq-sysfs.c

@@ -318,7 +318,7 @@ int __blk_mq_register_dev(struct device *dev, struct request_queue *q)
 
 	kobject_uevent(&q->mq_kobj, KOBJ_ADD);
 
-	blk_mq_debugfs_register(q, kobject_name(&dev->kobj));
+	blk_mq_debugfs_register(q);
 
 	queue_for_each_hw_ctx(q, hctx, i) {
 		ret = blk_mq_register_hctx(hctx);

block/blk-mq.h

@@ -87,13 +87,12 @@ extern void blk_mq_hctx_kobj_init(struct blk_mq_hw_ctx *hctx);
  * debugfs helpers
  */
 #ifdef CONFIG_BLK_DEBUG_FS
-int blk_mq_debugfs_register(struct request_queue *q, const char *name);
+int blk_mq_debugfs_register(struct request_queue *q);
 void blk_mq_debugfs_unregister(struct request_queue *q);
 int blk_mq_debugfs_register_hctxs(struct request_queue *q);
 void blk_mq_debugfs_unregister_hctxs(struct request_queue *q);
 #else
-static inline int blk_mq_debugfs_register(struct request_queue *q,
-					  const char *name)
+static inline int blk_mq_debugfs_register(struct request_queue *q)
 {
 	return 0;
 }