Merge branch 'ibmvnic-Fix-VLAN-and-other-device-errata'

Thomas Falcon says:

====================
ibmvnic: Fix VLAN and other device errata

This patch series contains fixes for VLAN and other backing hardware
errata. The VLAN fixes are mostly to account for the additional four
bytes VLAN header in TX descriptors and buffers, when applicable.

The other fixes for device errata are to pad small packets to avoid a
possible connection error that can occur when some devices attempt to
transmit small packets. The other fixes are GSO related. Some devices
cannot handle a smaller MSS or a packet with a single segment, so
disable GSO in those cases.

v2: Fix style mistake (unneeded brackets) in patch 3/4
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/ibm/ibmvnic.c

@@ -659,7 +659,7 @@ static int init_tx_pools(struct net_device *netdev)
 
 		if (alloc_long_term_buff(adapter, &tx_pool->long_term_buff,
 					 adapter->req_tx_entries_per_subcrq *
-					 adapter->req_mtu)) {
+					 (adapter->req_mtu + VLAN_HLEN))) {
 			release_tx_pools(adapter);
 			return -1;
 		}
@@ -1221,7 +1221,10 @@ static int build_hdr_data(u8 hdr_field, struct sk_buff *skb,
 	int len = 0;
 	u8 *hdr;
 
-	hdr_len[0] = sizeof(struct ethhdr);
+	if (skb_vlan_tagged(skb) && !skb_vlan_tag_present(skb))
+		hdr_len[0] = sizeof(struct vlan_ethhdr);
+	else
+		hdr_len[0] = sizeof(struct ethhdr);
 
 	if (skb->protocol == htons(ETH_P_IP)) {
 		hdr_len[1] = ip_hdr(skb)->ihl * 4;
@@ -1337,6 +1340,19 @@ static void build_hdr_descs_arr(struct ibmvnic_tx_buff *txbuff,
 			 txbuff->indir_arr + 1);
 }
 
+static int ibmvnic_xmit_workarounds(struct sk_buff *skb,
+				    struct net_device *netdev)
+{
+	/* For some backing devices, mishandling of small packets
+	 * can result in a loss of connection or TX stall. Device
+	 * architects recommend that no packet should be smaller
+	 * than the minimum MTU value provided to the driver, so
+	 * pad any packets to that length
+	 */
+	if (skb->len < netdev->min_mtu)
+		return skb_put_padto(skb, netdev->min_mtu);
+}
+
 static int ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev)
 {
 	struct ibmvnic_adapter *adapter = netdev_priv(netdev);
@@ -1374,6 +1390,13 @@ static int ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev)
 		goto out;
 	}
 
+	if (ibmvnic_xmit_workarounds(skb, adapter)) {
+		tx_dropped++;
+		tx_send_failed++;
+		ret = NETDEV_TX_OK;
+		goto out;
+	}
+
 	tx_pool = &adapter->tx_pool[queue_num];
 	tx_scrq = adapter->tx_scrq[queue_num];
 	txq = netdev_get_tx_queue(netdev, skb_get_queue_mapping(skb));
@@ -1391,9 +1414,9 @@ static int ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev)
 		if (tx_pool->tso_index == IBMVNIC_TSO_BUFS)
 			tx_pool->tso_index = 0;
 	} else {
-		offset = index * adapter->req_mtu;
+		offset = index * (adapter->req_mtu + VLAN_HLEN);
 		dst = tx_pool->long_term_buff.buff + offset;
-		memset(dst, 0, adapter->req_mtu);
+		memset(dst, 0, adapter->req_mtu + VLAN_HLEN);
 		data_dma_addr = tx_pool->long_term_buff.addr + offset;
 	}
 
@@ -2026,6 +2049,23 @@ static int ibmvnic_change_mtu(struct net_device *netdev, int new_mtu)
 	return wait_for_reset(adapter);
 }
 
+static netdev_features_t ibmvnic_features_check(struct sk_buff *skb,
+						struct net_device *dev,
+						netdev_features_t features)
+{
+	/* Some backing hardware adapters can not
+	 * handle packets with a MSS less than 224
+	 * or with only one segment.
+	 */
+	if (skb_is_gso(skb)) {
+		if (skb_shinfo(skb)->gso_size < 224 ||
+		    skb_shinfo(skb)->gso_segs == 1)
+			features &= ~NETIF_F_GSO_MASK;
+	}
+
+	return features;
+}
+
 static const struct net_device_ops ibmvnic_netdev_ops = {
 	.ndo_open		= ibmvnic_open,
 	.ndo_stop		= ibmvnic_close,
@@ -2038,6 +2078,7 @@ static const struct net_device_ops ibmvnic_netdev_ops = {
 	.ndo_poll_controller	= ibmvnic_netpoll_controller,
 #endif
 	.ndo_change_mtu		= ibmvnic_change_mtu,
+	.ndo_features_check     = ibmvnic_features_check,
 };
 
 /* ethtool functions */