netdev - [PATCH net-next 08/15] mlxsw: spectrum_router: Do not assume RTNL is taken during nexthop init

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Date:   Thu, 20 Feb 2020 09:07:53 +0200
From:   Ido Schimmel <idosch@...sch.org>
To:     netdev@...r.kernel.org
Cc:     davem@...emloft.net, jiri@...lanox.com, mlxsw@...lanox.com,
        Ido Schimmel <idosch@...lanox.com>
Subject: [PATCH net-next 08/15] mlxsw: spectrum_router: Do not assume RTNL is taken during nexthop init

From: Ido Schimmel <idosch@...lanox.com>

RTNL is going to be removed from route insertion path, so use
__in_dev_get_rcu() from an RCU read-side critical section instead of
__in_dev_get_rtnl() which assumes RTNL is taken.

Signed-off-by: Ido Schimmel <idosch@...lanox.com>
Acked-by: Jiri Pirko <jiri@...lanox.com>
---
 drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
index def75d7fcd06..28dca7aa4ce0 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
@@ -3840,10 +3840,14 @@ static int mlxsw_sp_nexthop4_init(struct mlxsw_sp *mlxsw_sp,
 	if (!dev)
 		return 0;
 
-	in_dev = __in_dev_get_rtnl(dev);
+	rcu_read_lock();
+	in_dev = __in_dev_get_rcu(dev);
 	if (in_dev && IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
-	    fib_nh->fib_nh_flags & RTNH_F_LINKDOWN)
+	    fib_nh->fib_nh_flags & RTNH_F_LINKDOWN) {
+		rcu_read_unlock();
 		return 0;
+	}
+	rcu_read_unlock();
 
 	err = mlxsw_sp_nexthop4_type_init(mlxsw_sp, nh, fib_nh);
 	if (err)
-- 
2.24.1