From: Ido Schimmel <idosch@mellanox.com>
Date: Fri, 21 Feb 2020 19:54:09 +0200
Subject: mlxsw: spectrum_router: Introduce router lock
Patch-mainline: v5.7-rc1
Git-commit: 20bf5d82bbec128c3ead91c6f98cfcd45df21013
References: bsc#1176774

Introduce a mutex to protect the internal structure of the routing code.
A single lock is added instead of a more fine-grained and complicated
locking scheme because there is not a lot of concurrency in the routing
code.

The main motivation is remove the dependence on RTNL lock, which is
currently used by both the process pushing routes to the kernel and the
workqueue pushing the routes to the underlying device.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c |    4 ++++
 drivers/net/ethernet/mellanox/mlxsw/spectrum_router.h |    1 +
 2 files changed, 5 insertions(+)

--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
@@ -17,6 +17,7 @@
 #include <linux/refcount.h>
 #include <linux/jhash.h>
 #include <linux/net_namespace.h>
+#include <linux/mutex.h>
 #include <net/netevent.h>
 #include <net/neighbour.h>
 #include <net/arp.h>
@@ -8065,6 +8066,7 @@ int mlxsw_sp_router_init(struct mlxsw_sp
 	router = kzalloc(sizeof(*mlxsw_sp->router), GFP_KERNEL);
 	if (!router)
 		return -ENOMEM;
+	mutex_init(&router->lock);
 	mlxsw_sp->router = router;
 	router->mlxsw_sp = mlxsw_sp;
 
@@ -8168,6 +8170,7 @@ err_router_init:
 err_register_inet6addr_notifier:
 	unregister_inetaddr_notifier(&router->inetaddr_nb);
 err_register_inetaddr_notifier:
+	mutex_destroy(&mlxsw_sp->router->lock);
 	kfree(mlxsw_sp->router);
 	return err;
 }
@@ -8188,5 +8191,6 @@ void mlxsw_sp_router_fini(struct mlxsw_s
 	__mlxsw_sp_router_fini(mlxsw_sp);
 	unregister_inet6addr_notifier(&mlxsw_sp->router->inet6addr_nb);
 	unregister_inetaddr_notifier(&mlxsw_sp->router->inetaddr_nb);
+	mutex_destroy(&mlxsw_sp->router->lock);
 	kfree(mlxsw_sp->router);
 }
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.h
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.h
@@ -47,6 +47,7 @@ struct mlxsw_sp_router {
 	u32 adj_discard_index;
 	bool adj_discard_index_valid;
 	struct mlxsw_sp_router_nve_decap nve_decap_config;
+	struct mutex lock; /* Protects shared router resources */
 };
 
 struct mlxsw_sp_rif_ipip_lb;