From: Ido Schimmel <idosch@mellanox.com>
Date: Fri, 21 Feb 2020 19:54:10 +0200
Subject: mlxsw: spectrum_router: Take router lock from inside routing code
Patch-mainline: v5.7-rc1
Git-commit: 894276e85c1602b0b7e309ed03700380cdf3245c
References: bsc#1176774

There are several work items in the routing code that currently rely on
RTNL lock to guard against concurrent changes. Have these work items
acquire the router lock in preparation for the removal for RTNL lock
from the routing code.

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 |   24 ++++++++++++------
 1 file changed, 17 insertions(+), 7 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
@@ -2278,10 +2278,9 @@ __mlxsw_sp_router_neighs_update_rauhtd(s
 	int i, num_rec;
 	int err;
 
-	/* Make sure the neighbour's netdev isn't removed in the
-	 * process.
-	 */
 	rtnl_lock();
+	/* Ensure the RIF we read from the device does not change mid-dump. */
+	mutex_lock(&mlxsw_sp->router->lock);
 	do {
 		mlxsw_reg_rauhtd_pack(rauhtd_pl, type);
 		err = mlxsw_reg_query(mlxsw_sp->core, MLXSW_REG(rauhtd),
@@ -2295,6 +2294,7 @@ __mlxsw_sp_router_neighs_update_rauhtd(s
 			mlxsw_sp_router_neigh_rec_process(mlxsw_sp, rauhtd_pl,
 							  i);
 	} while (mlxsw_sp_router_rauhtd_is_full(rauhtd_pl));
+	mutex_unlock(&mlxsw_sp->router->lock);
 	rtnl_unlock();
 
 	return err;
@@ -2326,14 +2326,15 @@ static void mlxsw_sp_router_neighs_updat
 {
 	struct mlxsw_sp_neigh_entry *neigh_entry;
 
-	/* Take RTNL mutex here to prevent lists from changes */
 	rtnl_lock();
+	mutex_lock(&mlxsw_sp->router->lock);
 	list_for_each_entry(neigh_entry, &mlxsw_sp->router->nexthop_neighs_list,
 			    nexthop_neighs_list_node)
 		/* If this neigh have nexthops, make the kernel think this neigh
 		 * is active regardless of the traffic.
 		 */
 		neigh_event_send(neigh_entry->key.n, NULL);
+	mutex_unlock(&mlxsw_sp->router->lock);
 	rtnl_unlock();
 }
 
@@ -2374,14 +2375,14 @@ static void mlxsw_sp_router_probe_unreso
 	 * the nexthop wouldn't get offloaded until the neighbor is resolved
 	 * but it wouldn't get resolved ever in case traffic is flowing in HW
 	 * using different nexthop.
-	 *
-	 * Take RTNL mutex here to prevent lists from changes.
 	 */
 	rtnl_lock();
+	mutex_lock(&router->lock);
 	list_for_each_entry(neigh_entry, &router->nexthop_neighs_list,
 			    nexthop_neighs_list_node)
 		if (!neigh_entry->connected)
 			neigh_event_send(neigh_entry->key.n, NULL);
+	mutex_unlock(&router->lock);
 	rtnl_unlock();
 
 	mlxsw_core_schedule_dw(&router->nexthop_probe_dw,
@@ -2521,6 +2522,7 @@ static void mlxsw_sp_router_neigh_event_
 	read_unlock_bh(&n->lock);
 
 	rtnl_lock();
+	mutex_lock(&mlxsw_sp->router->lock);
 	mlxsw_sp_span_respin(mlxsw_sp);
 
 	entry_connected = nud_state & NUD_VALID && !dead;
@@ -2542,6 +2544,7 @@ static void mlxsw_sp_router_neigh_event_
 		mlxsw_sp_neigh_entry_destroy(mlxsw_sp, neigh_entry);
 
 out:
+	mutex_unlock(&mlxsw_sp->router->lock);
 	rtnl_unlock();
 	neigh_release(n);
 	kfree(net_work);
@@ -5949,8 +5952,8 @@ static void mlxsw_sp_router_fib4_event_w
 	struct mlxsw_sp *mlxsw_sp = fib_work->mlxsw_sp;
 	int err;
 
-	/* Protect internal structures from changes */
 	rtnl_lock();
+	mutex_lock(&mlxsw_sp->router->lock);
 	mlxsw_sp_span_respin(mlxsw_sp);
 
 	switch (fib_work->event) {
@@ -5972,6 +5975,7 @@ static void mlxsw_sp_router_fib4_event_w
 		fib_info_put(fib_work->fnh_info.fib_nh->nh_parent);
 		break;
 	}
+	mutex_unlock(&mlxsw_sp->router->lock);
 	rtnl_unlock();
 	kfree(fib_work);
 }
@@ -5984,6 +5988,7 @@ static void mlxsw_sp_router_fib6_event_w
 	int err;
 
 	rtnl_lock();
+	mutex_lock(&mlxsw_sp->router->lock);
 	mlxsw_sp_span_respin(mlxsw_sp);
 
 	switch (fib_work->event) {
@@ -6010,6 +6015,7 @@ static void mlxsw_sp_router_fib6_event_w
 		mlxsw_sp_router_fib6_work_fini(&fib_work->fib6_work);
 		break;
 	}
+	mutex_unlock(&mlxsw_sp->router->lock);
 	rtnl_unlock();
 	kfree(fib_work);
 }
@@ -6023,6 +6029,7 @@ static void mlxsw_sp_router_fibmr_event_
 	int err;
 
 	rtnl_lock();
+	mutex_lock(&mlxsw_sp->router->lock);
 	switch (fib_work->event) {
 	case FIB_EVENT_ENTRY_REPLACE: /* fall through */
 	case FIB_EVENT_ENTRY_ADD:
@@ -6051,6 +6058,7 @@ static void mlxsw_sp_router_fibmr_event_
 		dev_put(fib_work->ven_info.dev);
 		break;
 	}
+	mutex_unlock(&mlxsw_sp->router->lock);
 	rtnl_unlock();
 	kfree(fib_work);
 }
@@ -7063,6 +7071,7 @@ static void mlxsw_sp_inet6addr_event_wor
 	struct mlxsw_sp_rif *rif;
 
 	rtnl_lock();
+	mutex_lock(&mlxsw_sp->router->lock);
 
 	rif = mlxsw_sp_rif_find_by_dev(mlxsw_sp, dev);
 	if (!mlxsw_sp_rif_should_config(rif, dev, event))
@@ -7070,6 +7079,7 @@ static void mlxsw_sp_inet6addr_event_wor
 
 	__mlxsw_sp_inetaddr_event(mlxsw_sp, dev, event, NULL);
 out:
+	mutex_unlock(&mlxsw_sp->router->lock);
 	rtnl_unlock();
 	dev_put(dev);
 	kfree(inet6addr_work);