Subject: [net 09/16] net/mlx5e: reset XPS on error flow if netdev isn't registered yet

From: Saeed Mahameed <[email-masked]>
Date: Tue, 18 May 2021 23:05:16 -0700

From: Saeed Mahameed <[email-masked]>

mlx5e_attach_netdev can be called prior to registering the netdevice:
Example stack:

ipoib_new_child_link ->
ipoib_intf_init->
rdma_init_netdev->
mlx5_rdma_setup_rn->

mlx5e_attach_netdev->
mlx5e_num_channels_changed ->
mlx5e_set_default_xps_cpumasks ->
netif_set_xps_queue ->
__netif_set_xps_queue -> kmalloc

If any later stage fails at any point after mlx5e_num_channels_changed()
returns, XPS allocated maps will never be freed as they
are only freed during netdev unregistration, which will never happen for
yet to be registered netdevs.

Fixes: 3909a12e7913 ("net/mlx5e: Fix configuration of XPS cpumasks and netdev queues in corner cases")
Signed-off-by: Saeed Mahameed <[email-masked]>
Signed-off-by: Aya Levin <[email-masked]>
Reviewed-by: Tariq Toukan <[email-masked]>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index bca832cdc4cb..89937b055070 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -5229,6 +5229,11 @@ static void mlx5e_update_features(struct net_device *netdev)
 	rtnl_unlock();
 }
 
+static void mlx5e_reset_channels(struct net_device *netdev)
+{
+	netdev_reset_tc(netdev);
+}
+
 int mlx5e_attach_netdev(struct mlx5e_priv *priv)
 {
 	const bool take_rtnl = priv->netdev->reg_state == NETREG_REGISTERED;
@@ -5283,6 +5288,7 @@ int mlx5e_attach_netdev(struct mlx5e_priv *priv)
 	profile->cleanup_tx(priv);
 
 out:
+	mlx5e_reset_channels(priv->netdev);
 	set_bit(MLX5E_STATE_DESTROYING, &priv->state);
 	cancel_work_sync(&priv->update_stats_work);
 	return err;
@@ -5300,6 +5306,7 @@ void mlx5e_detach_netdev(struct mlx5e_priv *priv)
 
 	profile->cleanup_rx(priv);
 	profile->cleanup_tx(priv);
+	mlx5e_reset_channels(priv->netdev);
 	cancel_work_sync(&priv->update_stats_work);
 }
 
-- 
2.31.1