net: marvell: prestera: add delayed wq and flush wq on deinit

Flushing workqueues ensures, that no more pending works, related to just
unregistered or deinitialized notifiers. After that we can free memory.

Delayed wq will be used for neighbours in next patches.
Co-developed-by: Taras Chornyi <tchornyi@marvell.com>
Signed-off-by: Taras Chornyi <tchornyi@marvell.com>
Co-developed-by: Oleksandr Mazur <oleksandr.mazur@plvision.eu>
Signed-off-by: Oleksandr Mazur <oleksandr.mazur@plvision.eu>
Signed-off-by: Yevhen Orlov <yevhen.orlov@plvision.eu>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/marvell/prestera/prestera.h

@@ -367,6 +367,8 @@ int prestera_port_cfg_mac_write(struct prestera_port *port,
 struct prestera_port *prestera_port_dev_lower_find(struct net_device *dev);
 
 void prestera_queue_work(struct work_struct *work);
+void prestera_queue_delayed_work(struct delayed_work *work, unsigned long delay);
+void prestera_queue_drain(void);
 
 int prestera_port_learning_set(struct prestera_port *port, bool learn_enable);
 int prestera_port_uc_flood_set(struct prestera_port *port, bool flood);

drivers/net/ethernet/marvell/prestera/prestera_main.c

@@ -36,6 +36,17 @@ void prestera_queue_work(struct work_struct *work)
 	queue_work(prestera_owq, work);
 }
 
+void prestera_queue_delayed_work(struct delayed_work *work, unsigned long delay)
+{
+	queue_delayed_work(prestera_wq, work, delay);
+}
+
+void prestera_queue_drain(void)
+{
+	drain_workqueue(prestera_wq);
+	drain_workqueue(prestera_owq);
+}
+
 int prestera_port_learning_set(struct prestera_port *port, bool learn)
 {
 	return prestera_hw_port_learning_set(port, learn);

drivers/net/ethernet/marvell/prestera/prestera_router.c

@@ -639,6 +639,7 @@ void prestera_router_fini(struct prestera_switch *sw)
 	unregister_fib_notifier(&init_net, &sw->router->fib_nb);
 	unregister_inetaddr_notifier(&sw->router->inetaddr_nb);
 	unregister_inetaddr_validator_notifier(&sw->router->inetaddr_valid_nb);
+	prestera_queue_drain();
 
 	prestera_k_arb_abort(sw);