[PATCH net-next] net: stmmac: Fix VLAN filtering when HW does not support it

[Jose Abreu]

If we don't have any filters available we can't rely upon the return
code of stmmac_add_hw_vlan_rx_fltr() / stmmac_del_hw_vlan_rx_fltr(). Add
a check for this.

Fixes: ed64639bc1e0 ("net: stmmac: Add support for VLAN Rx filtering")
Signed-off-by: Jose Abreu <Jose.Abreu@xxxxxxxxxxxx>

---
Cc: Giuseppe Cavallaro <peppe.cavallaro@xxxxxx>
Cc: Alexandre Torgue <alexandre.torgue@xxxxxx>
Cc: Jose Abreu <joabreu@xxxxxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Maxime Coquelin <mcoquelin.stm32@xxxxxxxxx>
Cc: netdev@xxxxxxxxxxxxxxx
Cc: linux-stm32@xxxxxxxxxxxxxxxxxxxxxxxxxxxx
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index b77d2faa580f..bd35a3df871d 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -4570,9 +4570,13 @@ static int stmmac_vlan_rx_add_vid(struct net_device *ndev, __be16 proto, u16 vid
 		return ret;
 	}
 
-	ret = stmmac_add_hw_vlan_rx_fltr(priv, ndev, priv->hw, proto, vid);
+	if (priv->hw->num_vlan) {
+		ret = stmmac_add_hw_vlan_rx_fltr(priv, ndev, priv->hw, proto, vid);
+		if (ret)
+			return ret;
+	}
 
-	return ret;
+	return 0;
 }
 
 static int stmmac_vlan_rx_kill_vid(struct net_device *ndev, __be16 proto, u16 vid)
@@ -4585,9 +4589,12 @@ static int stmmac_vlan_rx_kill_vid(struct net_device *ndev, __be16 proto, u16 vi
 		is_double = true;
 
 	clear_bit(vid, priv->active_vlans);
-	ret = stmmac_del_hw_vlan_rx_fltr(priv, ndev, priv->hw, proto, vid);
-	if (ret)
-		return ret;
+
+	if (priv->hw->num_vlan) {
+		ret = stmmac_del_hw_vlan_rx_fltr(priv, ndev, priv->hw, proto, vid);
+		if (ret)
+			return ret;
+	}
 
 	return stmmac_vlan_update(priv, is_double);
 }
-- 
2.7.4