net: ena: Fix rx_copybreak value update

[ Upstream commit c7062aa ]

Make the upper bound on rx_copybreak tighter, by
making sure it is smaller than the minimum of mtu and
ENA_PAGE_SIZE. With the current upper bound of mtu,
rx_copybreak can be larger than a page. Such large
rx_copybreak will not bring any performance benefit to
the user and therefore makes no sense.

In addition, the value update was only reflected in
the adapter structure, but not applied for each ring,
causing it to not take effect.

Fixes: 1738cd3 ("net: ena: Add a driver for Amazon Elastic Network Adapters (ENA)")
Signed-off-by: Osama Abboud <osamaabb@amazon.com>
Signed-off-by: Arthur Kiyanovski <akiyano@amazon.com>
Signed-off-by: David Arinzon <darinzon@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/net/ethernet/amazon/ena/ena_ethtool.c

@@ -880,11 +880,7 @@ static int ena_set_tunable(struct net_device *netdev,
 	switch (tuna->id) {
 	case ETHTOOL_RX_COPYBREAK:
 		len = *(u32 *)data;
-		if (len > adapter->netdev->mtu) {
-			ret = -EINVAL;
-			break;
-		}
-		adapter->rx_copybreak = len;
+		ret = ena_set_rx_copybreak(adapter, len);
 		break;
 	default:
 		ret = -EINVAL;

drivers/net/ethernet/amazon/ena/ena_netdev.c

@@ -2829,6 +2829,24 @@ int ena_update_queue_sizes(struct ena_adapter *adapter,
 	return dev_was_up ? ena_up(adapter) : 0;
 }
 
+int ena_set_rx_copybreak(struct ena_adapter *adapter, u32 rx_copybreak)
+{
+	struct ena_ring *rx_ring;
+	int i;
+
+	if (rx_copybreak > min_t(u16, adapter->netdev->mtu, ENA_PAGE_SIZE))
+		return -EINVAL;
+
+	adapter->rx_copybreak = rx_copybreak;
+
+	for (i = 0; i < adapter->num_io_queues; i++) {
+		rx_ring = &adapter->rx_ring[i];
+		rx_ring->rx_copybreak = rx_copybreak;
+	}
+
+	return 0;
+}
+
 int ena_update_queue_count(struct ena_adapter *adapter, u32 new_channel_count)
 {
 	struct ena_com_dev *ena_dev = adapter->ena_dev;

drivers/net/ethernet/amazon/ena/ena_netdev.h

@@ -404,6 +404,8 @@ int ena_update_queue_sizes(struct ena_adapter *adapter,
 
 int ena_update_queue_count(struct ena_adapter *adapter, u32 new_channel_count);
 
+int ena_set_rx_copybreak(struct ena_adapter *adapter, u32 rx_copybreak);
+
 int ena_get_sset_count(struct net_device *netdev, int sset);
 
 enum ena_xdp_errors_t {