[PATCH net-next v2 2/2] net: stmmac: Don't set or get RSS parameters when not supported

[Maxime Chevallier]

The RSS kselftests fail on stmmac, and this is partly due to the driver
reporting bogus data for the RSS ops :

 - ethtool -x reports an indirection table and a key while the hardware
   doesn't have any of that
 - ethtool -X fails with -EINVAL.

Let's return early in the rss ops if we know the hardware and platform
don't support RSS.

Signed-off-by: Maxime Chevallier <maxime.chevallier at bootlin.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
index 154cc0c7623d..b78dc301d70d 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
@@ -927,6 +927,9 @@ static u32 stmmac_get_rxfh_key_size(struct net_device *dev)
 {
 	struct stmmac_priv *priv = netdev_priv(dev);
 
+	if (!stmmac_rss_is_supported(priv))
+		return 0;
+
 	return sizeof(priv->rss.key);
 }
 
@@ -934,6 +937,9 @@ static u32 stmmac_get_rxfh_indir_size(struct net_device *dev)
 {
 	struct stmmac_priv *priv = netdev_priv(dev);
 
+	if (!stmmac_rss_is_supported(priv))
+		return 0;
+
 	return ARRAY_SIZE(priv->rss.table);
 }
 
@@ -943,6 +949,9 @@ static int stmmac_get_rxfh(struct net_device *dev,
 	struct stmmac_priv *priv = netdev_priv(dev);
 	int i;
 
+	if (!stmmac_rss_is_supported(priv))
+		return -EOPNOTSUPP;
+
 	if (rxfh->indir) {
 		for (i = 0; i < ARRAY_SIZE(priv->rss.table); i++)
 			rxfh->indir[i] = priv->rss.table[i];
@@ -962,6 +971,9 @@ static int stmmac_set_rxfh(struct net_device *dev,
 	struct stmmac_priv *priv = netdev_priv(dev);
 	int i;
 
+	if (!stmmac_rss_is_supported(priv))
+		return -EOPNOTSUPP;
+
 	if (rxfh->hfunc != ETH_RSS_HASH_NO_CHANGE &&
 	    rxfh->hfunc != ETH_RSS_HASH_TOP)
 		return -EOPNOTSUPP;
-- 
2.55.0