[PATCH net-next v2 08/14] net: stmmac: move check for hardware checksum supported

[Russell King (Oracle)]

Add a check in .ndo_features_check() to indicate whether hardware
checksum can be performed on the skbuff. Where hardware checksum is
not supported - either because the channel does not support Tx COE
or the skb isn't suitable (stmmac uses a tighter test than
can_checksum_protocol()) we also need to disable TSO, which will be
done by harmonize_features() in net/core/dev.c

This fixes a bug where a channel which has COE disabled may still
receive TSO skbuffs.

Signed-off-by: Russell King (Oracle) <rmk+kernel at armlinux.org.uk>
---
 .../net/ethernet/stmicro/stmmac/stmmac_main.c | 38 +++++++++----------
 1 file changed, 19 insertions(+), 19 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index c67f042a90af..d3cbe71b9af1 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -4757,22 +4757,6 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
 	/* Check if VLAN can be inserted by HW */
 	has_vlan = stmmac_vlan_insert(priv, skb, tx_q);
 
-	csum_insertion = (skb->ip_summed == CHECKSUM_PARTIAL);
-	/* DWMAC IPs can be synthesized to support tx coe only for a few tx
-	 * queues. In that case, checksum offloading for those queues that don't
-	 * support tx coe needs to fallback to software checksum calculation.
-	 *
-	 * Packets that won't trigger the COE e.g. most DSA-tagged packets will
-	 * also have to be checksummed in software.
-	 */
-	if (csum_insertion &&
-	    (priv->plat->tx_queues_cfg[queue].coe_unsupported ||
-	     !stmmac_has_ip_ethertype(skb))) {
-		if (unlikely(skb_checksum_help(skb)))
-			goto dma_map_err;
-		csum_insertion = !csum_insertion;
-	}
-
 	entry = tx_q->cur_tx;
 	first_entry = entry;
 	WARN_ON(tx_q->tx_skbuff[first_entry]);
@@ -4788,6 +4772,8 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
 	if (enh_desc)
 		is_jumbo = stmmac_is_jumbo_frm(priv, skb->len, enh_desc);
 
+	csum_insertion = skb->ip_summed == CHECKSUM_PARTIAL;
+
 	if (unlikely(is_jumbo)) {
 		entry = stmmac_jumbo_frm(priv, tx_q, skb, csum_insertion);
 		if (unlikely(entry < 0) && (entry != -EINVAL))
@@ -4949,11 +4935,25 @@ static netdev_features_t stmmac_features_check(struct sk_buff *skb,
 					       struct net_device *dev,
 					       netdev_features_t features)
 {
-	u16 queue;
+	struct stmmac_priv *priv = netdev_priv(dev);
+	u16 queue = skb_get_queue_mapping(skb);
+
+	/* DWMAC IPs can be synthesized to support tx coe only for a few tx
+	 * queues. In that case, checksum offloading for those queues that don't
+	 * support tx coe needs to fallback to software checksum calculation.
+	 *
+	 * Packets that won't trigger the COE e.g. most DSA-tagged packets will
+	 * also have to be checksummed in software.
+	 *
+	 * Note that disabling hardware checksumming also disables TSO. See
+	 * harmonize_features() in net/core/dev.c
+	 */
+	if (priv->plat->tx_queues_cfg[queue].coe_unsupported ||
+	    !stmmac_has_ip_ethertype(skb))
+		features &= ~(NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM);
 
 	if (skb_is_gso(skb)) {
-		queue = skb_get_queue_mapping(skb);
-		if (!stmmac_tso_channel_permitted(netdev_priv(dev), queue) ||
+		if (!stmmac_tso_channel_permitted(priv, queue) ||
 		    !stmmac_tso_valid_packet(skb))
 			features &= ~NETIF_F_GSO_MASK;
 
-- 
2.47.3