3 files changed, 143 insertions, 11 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index fa5671307b90..b4eae18390cc 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -405,6 +405,9 @@ struct net_device
         struct list_head        qdisc_list;
         unsigned long           tx_queue_len;   /* Max frames per queue allowed */
 
+        /* Partially transmitted GSO packet. */
+        struct sk_buff          *gso_skb;
+
         /* ingress path synchronizer */
         spinlock_t              ingress_lock;
         struct Qdisc            *qdisc_ingress;
@@ -539,6 +542,7 @@ struct packet_type {
                                          struct net_device *,
                                          struct packet_type *,
                                          struct net_device *);
+        struct sk_buff          *(*gso_segment)(struct sk_buff *skb, int sg);
         void                    *af_packet_priv;
         struct list_head        list;
 };
@@ -689,7 +693,8 @@ extern int		dev_change_name(struct net_device *, char *);
 extern int              dev_set_mtu(struct net_device *, int);
 extern int              dev_set_mac_address(struct net_device *,
                                             struct sockaddr *);
-extern void             dev_queue_xmit_nit(struct sk_buff *skb, struct net_device *dev);
+extern int              dev_hard_start_xmit(struct sk_buff *skb,
+                                            struct net_device *dev);
 
 extern void             dev_init(void);
 
@@ -963,6 +968,7 @@ extern int		netdev_max_backlog;
 extern int              weight_p;
 extern int              netdev_set_master(struct net_device *dev, struct net_device *master);
 extern int skb_checksum_help(struct sk_buff *skb, int inward);
+extern struct sk_buff *skb_gso_segment(struct sk_buff *skb, int sg);
 #ifdef CONFIG_BUG
 extern void netdev_rx_csum_fault(struct net_device *dev);
 #else
diff --git a/net/core/dev.c b/net/core/dev.c
index 29e3888102bc..d293e0f90a0c 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -116,6 +116,7 @@
 #include <asm/current.h>
 #include <linux/audit.h>
 #include <linux/dmaengine.h>
+#include <linux/err.h>
 
 /*
  *      The list of packet types we will receive (as opposed to discard)
@@ -1048,7 +1049,7 @@ static inline void net_timestamp(struct sk_buff *skb)
  *      taps currently in use.
  */
 
-void dev_queue_xmit_nit(struct sk_buff *skb, struct net_device *dev)
+static void dev_queue_xmit_nit(struct sk_buff *skb, struct net_device *dev)
 {
         struct packet_type *ptype;
 
@@ -1186,6 +1187,40 @@ out:
         return ret;
 }
 
+/**
+ *      skb_gso_segment - Perform segmentation on skb.
+ *      @skb: buffer to segment
+ *      @sg: whether scatter-gather is supported on the target.
+ *
+ *      This function segments the given skb and returns a list of segments.
+ */
+struct sk_buff *skb_gso_segment(struct sk_buff *skb, int sg)
+{
+        struct sk_buff *segs = ERR_PTR(-EPROTONOSUPPORT);
+        struct packet_type *ptype;
+        int type = skb->protocol;
+
+        BUG_ON(skb_shinfo(skb)->frag_list);
+        BUG_ON(skb->ip_summed != CHECKSUM_HW);
+
+        skb->mac.raw = skb->data;
+        skb->mac_len = skb->nh.raw - skb->data;
+        __skb_pull(skb, skb->mac_len);
+
+        rcu_read_lock();
+        list_for_each_entry_rcu(ptype, &ptype_base[ntohs(type) & 15], list) {
+                if (ptype->type == type && !ptype->dev && ptype->gso_segment) {
+                        segs = ptype->gso_segment(skb, sg);
+                        break;
+                }
+        }
+        rcu_read_unlock();
+
+        return segs;
+}
+
+EXPORT_SYMBOL(skb_gso_segment);
+
 /* Take action when hardware reception checksum errors are detected. */
 #ifdef CONFIG_BUG
 void netdev_rx_csum_fault(struct net_device *dev)
@@ -1222,6 +1257,86 @@ static inline int illegal_highdma(struct net_device *dev, struct sk_buff *skb)
 #define illegal_highdma(dev, skb)       (0)
 #endif
 
+struct dev_gso_cb {
+        void (*destructor)(struct sk_buff *skb);
+};
+
+#define DEV_GSO_CB(skb) ((struct dev_gso_cb *)(skb)->cb)
+
+static void dev_gso_skb_destructor(struct sk_buff *skb)
+{
+        struct dev_gso_cb *cb;
+
+        do {
+                struct sk_buff *nskb = skb->next;
+
+                skb->next = nskb->next;
+                nskb->next = NULL;
+                kfree_skb(nskb);
+        } while (skb->next);
+
+        cb = DEV_GSO_CB(skb);
+        if (cb->destructor)
+                cb->destructor(skb);
+}
+
+/**
+ *      dev_gso_segment - Perform emulated hardware segmentation on skb.
+ *      @skb: buffer to segment
+ *
+ *      This function segments the given skb and stores the list of segments
+ *      in skb->next.
+ */
+static int dev_gso_segment(struct sk_buff *skb)
+{
+        struct net_device *dev = skb->dev;
+        struct sk_buff *segs;
+
+        segs = skb_gso_segment(skb, dev->features & NETIF_F_SG &&
+                                    !illegal_highdma(dev, skb));
+        if (unlikely(IS_ERR(segs)))
+                return PTR_ERR(segs);
+
+        skb->next = segs;
+        DEV_GSO_CB(skb)->destructor = skb->destructor;
+        skb->destructor = dev_gso_skb_destructor;
+
+        return 0;
+}
+
+int dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+        if (likely(!skb->next)) {
+                if (netdev_nit)
+                        dev_queue_xmit_nit(skb, dev);
+
+                if (!netif_needs_gso(dev, skb))
+                        return dev->hard_start_xmit(skb, dev);
+
+                if (unlikely(dev_gso_segment(skb)))
+                        goto out_kfree_skb;
+        }
+
+        do {
+                struct sk_buff *nskb = skb->next;
+                int rc;
+
+                skb->next = nskb->next;
+                nskb->next = NULL;
+                rc = dev->hard_start_xmit(nskb, dev);
+                if (unlikely(rc)) {
+                        skb->next = nskb;
+                        return rc;
+                }
+        } while (skb->next);
+        
+        skb->destructor = DEV_GSO_CB(skb)->destructor;
+
+out_kfree_skb:
+        kfree_skb(skb);
+        return 0;
+}
+
 #define HARD_TX_LOCK(dev, cpu) {                        \
         if ((dev->features & NETIF_F_LLTX) == 0) {      \
                 netif_tx_lock(dev);                     \
@@ -1266,6 +1381,10 @@ int dev_queue_xmit(struct sk_buff *skb)
         struct Qdisc *q;
         int rc = -ENOMEM;
 
+        /* GSO will handle the following emulations directly. */
+        if (netif_needs_gso(dev, skb))
+                goto gso;
+
         if (skb_shinfo(skb)->frag_list &&
             !(dev->features & NETIF_F_FRAGLIST) &&
             __skb_linearize(skb))
@@ -1290,6 +1409,7 @@ int dev_queue_xmit(struct sk_buff *skb)
                 if (skb_checksum_help(skb, 0))
                         goto out_kfree_skb;
 
+gso:
         spin_lock_prefetch(&dev->queue_lock);
 
         /* Disable soft irqs for various locks below. Also 
@@ -1346,11 +1466,8 @@ int dev_queue_xmit(struct sk_buff *skb)
                         HARD_TX_LOCK(dev, cpu);
 
                         if (!netif_queue_stopped(dev)) {
-                                if (netdev_nit)
-                                        dev_queue_xmit_nit(skb, dev);
-
                                 rc = 0;
-                                if (!dev->hard_start_xmit(skb, dev)) {
+                                if (!dev_hard_start_xmit(skb, dev)) {
                                         HARD_TX_UNLOCK(dev);
                                         goto out;
                                 }
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 7aad0121232c..74d4a1dceeec 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -96,8 +96,11 @@ static inline int qdisc_restart(struct net_device *dev)
         struct sk_buff *skb;
 
         /* Dequeue packet */
-        if ((skb = q->dequeue(q)) != NULL) {
+        if (((skb = dev->gso_skb)) || ((skb = q->dequeue(q)))) {
                 unsigned nolock = (dev->features & NETIF_F_LLTX);
+
+                dev->gso_skb = NULL;
+
                 /*
                  * When the driver has LLTX set it does its own locking
                  * in start_xmit. No need to add additional overhead by
@@ -134,10 +137,8 @@ static inline int qdisc_restart(struct net_device *dev)
 
                         if (!netif_queue_stopped(dev)) {
                                 int ret;
-                                if (netdev_nit)
-                                        dev_queue_xmit_nit(skb, dev);
 
-                                ret = dev->hard_start_xmit(skb, dev);
+                                ret = dev_hard_start_xmit(skb, dev);
                                 if (ret == NETDEV_TX_OK) { 
                                         if (!nolock) {
                                                 netif_tx_unlock(dev);
@@ -171,7 +172,10 @@ static inline int qdisc_restart(struct net_device *dev)
                  */
 
 requeue:
-                q->ops->requeue(skb, q);
+                if (skb->next)
+                        dev->gso_skb = skb;
+                else
+                        q->ops->requeue(skb, q);
                 netif_schedule(dev);
                 return 1;
         }
@@ -593,6 +597,11 @@ void dev_deactivate(struct net_device *dev)
         /* Wait for outstanding qdisc_run calls. */
         while (test_bit(__LINK_STATE_QDISC_RUNNING, &dev->state))
                 yield();
+
+        if (dev->gso_skb) {
+                kfree_skb(dev->gso_skb);
+                dev->gso_skb = NULL;
+        }
 }
 
 void dev_init_scheduler(struct net_device *dev)