net: sched: remove the unused return value of unregister_qdisc

Return value of unregister_qdisc is unused, remove it.
Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
Link: https://lore.kernel.org/r/20220815030417.271894-1-shaozhengchao@huawei.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

include/net/pkt_sched.h

@@ -100,7 +100,7 @@ struct Qdisc *fifo_create_dflt(struct Qdisc *sch, struct Qdisc_ops *ops,
 			       struct netlink_ext_ack *extack);
 
 int register_qdisc(struct Qdisc_ops *qops);
-int unregister_qdisc(struct Qdisc_ops *qops);
+void unregister_qdisc(struct Qdisc_ops *qops);
 void qdisc_get_default(char *id, size_t len);
 int qdisc_set_default(const char *id);
 

net/sched/sch_api.c

@@ -171,7 +171,7 @@ int register_qdisc(struct Qdisc_ops *qops)
 }
 EXPORT_SYMBOL(register_qdisc);
 
-int unregister_qdisc(struct Qdisc_ops *qops)
+void unregister_qdisc(struct Qdisc_ops *qops)
 {
 	struct Qdisc_ops *q, **qp;
 	int err = -ENOENT;
@@ -186,7 +186,8 @@ int unregister_qdisc(struct Qdisc_ops *qops)
 		err = 0;
 	}
 	write_unlock(&qdisc_mod_lock);
-	return err;
+
+	WARN(err, "unregister qdisc(%s) failed\n", qops->id);
 }
 EXPORT_SYMBOL(unregister_qdisc);