qeth: rework TSO functions

The maximum TSO size OSA can handle is 15 * PAGE_SIZE. This
patch reduces gso_max_size to this value and adds some sanity
checks and statistics to the TSO implementation.
Since only layer 3 is able to do TSO move all TSO related functions
to the qeth_l3 module.

Signed-off-by: Frank Blaschka <frank.blaschka@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 58 insertions, 13 deletions

diff --git a/drivers/s390/net/qeth_l3_main.c b/drivers/s390/net/qeth_l3_main.c
index 03f67bb51e99..2048b4354216 100644
--- a/drivers/s390/net/qeth_l3_main.c
+++ b/drivers/s390/net/qeth_l3_main.c
@@ -41,6 +41,32 @@ static int qeth_l3_deregister_addr_entry(struct qeth_card *,
 static int __qeth_l3_set_online(struct ccwgroup_device *, int);
 static int __qeth_l3_set_offline(struct ccwgroup_device *, int);
 
+int qeth_l3_set_large_send(struct qeth_card *card,
+                enum qeth_large_send_types type)
+{
+        int rc = 0;
+
+        card->options.large_send = type;
+        if (card->dev == NULL)
+                return 0;
+
+        if (card->options.large_send == QETH_LARGE_SEND_TSO) {
+                if (qeth_is_supported(card, IPA_OUTBOUND_TSO)) {
+                        card->dev->features |= NETIF_F_TSO | NETIF_F_SG |
+                                        NETIF_F_HW_CSUM;
+                } else {
+                        card->dev->features &= ~(NETIF_F_TSO | NETIF_F_SG |
+                                        NETIF_F_HW_CSUM);
+                        card->options.large_send = QETH_LARGE_SEND_NO;
+                        rc = -EOPNOTSUPP;
+                }
+        } else {
+                card->dev->features &= ~(NETIF_F_TSO | NETIF_F_SG |
+                                        NETIF_F_HW_CSUM);
+                card->options.large_send = QETH_LARGE_SEND_NO;
+        }
+        return rc;
+}
 
 static int qeth_l3_isxdigit(char *buf)
 {
@@ -2686,6 +2712,24 @@ static void qeth_tx_csum(struct sk_buff *skb)
         *(__sum16 *)(skb->data + offset) = csum_fold(csum);
 }
 
+static inline int qeth_l3_tso_elements(struct sk_buff *skb)
+{
+        unsigned long tcpd = (unsigned long)tcp_hdr(skb) +
+                tcp_hdr(skb)->doff * 4;
+        int tcpd_len = skb->len - (tcpd - (unsigned long)skb->data);
+        int elements = PFN_UP(tcpd + tcpd_len) - PFN_DOWN(tcpd);
+        elements += skb_shinfo(skb)->nr_frags;
+        return elements;
+}
+
+static inline int qeth_l3_tso_check(struct sk_buff *skb)
+{
+        int len = ((unsigned long)tcp_hdr(skb) + tcp_hdr(skb)->doff * 4) -
+                (unsigned long)skb->data;
+        return (((unsigned long)skb->data & PAGE_MASK) !=
+                (((unsigned long)skb->data + len) & PAGE_MASK));
+}
+
 static int qeth_l3_hard_start_xmit(struct sk_buff *skb, struct net_device *dev)
 {
         int rc;
@@ -2779,16 +2823,21 @@ static int qeth_l3_hard_start_xmit(struct sk_buff *skb, struct net_device *dev)
         /* fix hardware limitation: as long as we do not have sbal
          * chaining we can not send long frag lists
          */
-        if ((large_send == QETH_LARGE_SEND_TSO) &&
-            ((skb_shinfo(new_skb)->nr_frags + 2) > 16)) {
-                if (skb_linearize(new_skb))
-                        goto tx_drop;
+        if (large_send == QETH_LARGE_SEND_TSO) {
+                if (qeth_l3_tso_elements(new_skb) + 1 > 16) {
+                        if (skb_linearize(new_skb))
+                                goto tx_drop;
+                        if (card->options.performance_stats)
+                                card->perf_stats.tx_lin++;
+                }
         }
 
         if ((large_send == QETH_LARGE_SEND_TSO) &&
             (cast_type == RTN_UNSPEC)) {
                 hdr = (struct qeth_hdr *)skb_push(new_skb,
                                                 sizeof(struct qeth_hdr_tso));
+                if (qeth_l3_tso_check(new_skb))
+                        QETH_DBF_MESSAGE(2, "tso skb misaligned\n");
                 memset(hdr, 0, sizeof(struct qeth_hdr_tso));
                 qeth_l3_fill_header(card, hdr, new_skb, ipv, cast_type);
                 qeth_tso_fill_header(card, hdr, new_skb);
@@ -2931,20 +2980,15 @@ static int qeth_l3_ethtool_set_rx_csum(struct net_device *dev, u32 data)
 static int qeth_l3_ethtool_set_tso(struct net_device *dev, u32 data)
 {
         struct qeth_card *card = dev->ml_priv;
+        int rc = 0;
 
         if (data) {
-                if (card->options.large_send == QETH_LARGE_SEND_NO) {
-                        if (card->info.type == QETH_CARD_TYPE_IQD)
-                                return -EPERM;
-                        else
-                                card->options.large_send = QETH_LARGE_SEND_TSO;
-                        dev->features |= NETIF_F_TSO;
-                }
+                rc = qeth_l3_set_large_send(card, QETH_LARGE_SEND_TSO);
         } else {
                 dev->features &= ~NETIF_F_TSO;
                 card->options.large_send = QETH_LARGE_SEND_NO;
         }
-        return 0;
+        return rc;
 }
 
 static const struct ethtool_ops qeth_l3_ethtool_ops = {
@@ -3060,6 +3104,7 @@ static int qeth_l3_setup_netdev(struct qeth_card *card)
                                 NETIF_F_HW_VLAN_RX |
                                 NETIF_F_HW_VLAN_FILTER;
         card->dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
+        card->dev->gso_max_size = 15 * PAGE_SIZE;
 
         SET_NETDEV_DEV(card->dev, &card->gdev->dev);
         return register_netdev(card->dev);
@@ -3189,7 +3234,7 @@ static int __qeth_l3_set_online(struct ccwgroup_device *gdev, int recovery_mode)
                 goto out_remove;
         } else
                 card->lan_online = 1;
-        qeth_set_large_send(card, card->options.large_send);
+        qeth_l3_set_large_send(card, card->options.large_send);
 
         rc = qeth_l3_setadapter_parms(card);
         if (rc)