[NET]: Clean up skb_linearize
[safe/jmp/linux-2.6] / net / core / dev.c
index 4fba549..91361bc 100644 (file)
 #include <net/iw_handler.h>
 #include <asm/current.h>
 #include <linux/audit.h>
+#include <linux/dmaengine.h>
 
 /*
  *     The list of packet types we will receive (as opposed to discard)
@@ -148,6 +149,12 @@ static DEFINE_SPINLOCK(ptype_lock);
 static struct list_head ptype_base[16];        /* 16 way hashed list */
 static struct list_head ptype_all;             /* Taps */
 
+#ifdef CONFIG_NET_DMA
+static struct dma_client *net_dma_client;
+static unsigned int net_dma_count;
+static spinlock_t net_dma_event_lock;
+#endif
+
 /*
  * The @dev_base list is protected by @dev_base_lock and the rtnl
  * semaphore.
@@ -1215,75 +1222,15 @@ static inline int illegal_highdma(struct net_device *dev, struct sk_buff *skb)
 #define illegal_highdma(dev, skb)      (0)
 #endif
 
-/* Keep head the same: replace data */
-int __skb_linearize(struct sk_buff *skb, gfp_t gfp_mask)
-{
-       unsigned int size;
-       u8 *data;
-       long offset;
-       struct skb_shared_info *ninfo;
-       int headerlen = skb->data - skb->head;
-       int expand = (skb->tail + skb->data_len) - skb->end;
-
-       if (skb_shared(skb))
-               BUG();
-
-       if (expand <= 0)
-               expand = 0;
-
-       size = skb->end - skb->head + expand;
-       size = SKB_DATA_ALIGN(size);
-       data = kmalloc(size + sizeof(struct skb_shared_info), gfp_mask);
-       if (!data)
-               return -ENOMEM;
-
-       /* Copy entire thing */
-       if (skb_copy_bits(skb, -headerlen, data, headerlen + skb->len))
-               BUG();
-
-       /* Set up shinfo */
-       ninfo = (struct skb_shared_info*)(data + size);
-       atomic_set(&ninfo->dataref, 1);
-       ninfo->tso_size = skb_shinfo(skb)->tso_size;
-       ninfo->tso_segs = skb_shinfo(skb)->tso_segs;
-       ninfo->nr_frags = 0;
-       ninfo->frag_list = NULL;
-
-       /* Offset between the two in bytes */
-       offset = data - skb->head;
-
-       /* Free old data. */
-       skb_release_data(skb);
-
-       skb->head = data;
-       skb->end  = data + size;
-
-       /* Set up new pointers */
-       skb->h.raw   += offset;
-       skb->nh.raw  += offset;
-       skb->mac.raw += offset;
-       skb->tail    += offset;
-       skb->data    += offset;
-
-       /* We are no longer a clone, even if we were. */
-       skb->cloned    = 0;
-
-       skb->tail     += skb->data_len;
-       skb->data_len  = 0;
-       return 0;
-}
-
 #define HARD_TX_LOCK(dev, cpu) {                       \
        if ((dev->features & NETIF_F_LLTX) == 0) {      \
-               spin_lock(&dev->xmit_lock);             \
-               dev->xmit_lock_owner = cpu;             \
+               netif_tx_lock(dev);                     \
        }                                               \
 }
 
 #define HARD_TX_UNLOCK(dev) {                          \
        if ((dev->features & NETIF_F_LLTX) == 0) {      \
-               dev->xmit_lock_owner = -1;              \
-               spin_unlock(&dev->xmit_lock);           \
+               netif_tx_unlock(dev);                   \
        }                                               \
 }
 
@@ -1321,7 +1268,7 @@ int dev_queue_xmit(struct sk_buff *skb)
 
        if (skb_shinfo(skb)->frag_list &&
            !(dev->features & NETIF_F_FRAGLIST) &&
-           __skb_linearize(skb, GFP_ATOMIC))
+           __skb_linearize(skb))
                goto out_kfree_skb;
 
        /* Fragmented skb is linearized if device does not support SG,
@@ -1330,7 +1277,7 @@ int dev_queue_xmit(struct sk_buff *skb)
         */
        if (skb_shinfo(skb)->nr_frags &&
            (!(dev->features & NETIF_F_SG) || illegal_highdma(dev, skb)) &&
-           __skb_linearize(skb, GFP_ATOMIC))
+           __skb_linearize(skb))
                goto out_kfree_skb;
 
        /* If packet is not checksummed and device does not support
@@ -1382,8 +1329,8 @@ int dev_queue_xmit(struct sk_buff *skb)
        /* The device has no queue. Common case for software devices:
           loopback, all the sorts of tunnels...
 
-          Really, it is unlikely that xmit_lock protection is necessary here.
-          (f.e. loopback and IP tunnels are clean ignoring statistics
+          Really, it is unlikely that netif_tx_lock protection is necessary
+          here.  (f.e. loopback and IP tunnels are clean ignoring statistics
           counters.)
           However, it is possible, that they rely on protection
           made by us here.
@@ -1846,6 +1793,19 @@ static void net_rx_action(struct softirq_action *h)
                }
        }
 out:
+#ifdef CONFIG_NET_DMA
+       /*
+        * There may not be any more sk_buffs coming right now, so push
+        * any pending DMA copies to hardware
+        */
+       if (net_dma_client) {
+               struct dma_chan *chan;
+               rcu_read_lock();
+               list_for_each_entry_rcu(chan, &net_dma_client->channels, client_node)
+                       dma_async_memcpy_issue_pending(chan);
+               rcu_read_unlock();
+       }
+#endif
        local_irq_enable();
        return;
 
@@ -2785,7 +2745,7 @@ int register_netdevice(struct net_device *dev)
        BUG_ON(dev->reg_state != NETREG_UNINITIALIZED);
 
        spin_lock_init(&dev->queue_lock);
-       spin_lock_init(&dev->xmit_lock);
+       spin_lock_init(&dev->_xmit_lock);
        dev->xmit_lock_owner = -1;
 #ifdef CONFIG_NET_CLS_ACT
        spin_lock_init(&dev->ingress_lock);
@@ -3300,6 +3260,88 @@ static int dev_cpu_callback(struct notifier_block *nfb,
 }
 #endif /* CONFIG_HOTPLUG_CPU */
 
+#ifdef CONFIG_NET_DMA
+/**
+ * net_dma_rebalance -
+ * This is called when the number of channels allocated to the net_dma_client
+ * changes.  The net_dma_client tries to have one DMA channel per CPU.
+ */
+static void net_dma_rebalance(void)
+{
+       unsigned int cpu, i, n;
+       struct dma_chan *chan;
+
+       lock_cpu_hotplug();
+
+       if (net_dma_count == 0) {
+               for_each_online_cpu(cpu)
+                       rcu_assign_pointer(per_cpu(softnet_data.net_dma, cpu), NULL);
+               unlock_cpu_hotplug();
+               return;
+       }
+
+       i = 0;
+       cpu = first_cpu(cpu_online_map);
+
+       rcu_read_lock();
+       list_for_each_entry(chan, &net_dma_client->channels, client_node) {
+               n = ((num_online_cpus() / net_dma_count)
+                  + (i < (num_online_cpus() % net_dma_count) ? 1 : 0));
+
+               while(n) {
+                       per_cpu(softnet_data.net_dma, cpu) = chan;
+                       cpu = next_cpu(cpu, cpu_online_map);
+                       n--;
+               }
+               i++;
+       }
+       rcu_read_unlock();
+
+       unlock_cpu_hotplug();
+}
+
+/**
+ * netdev_dma_event - event callback for the net_dma_client
+ * @client: should always be net_dma_client
+ * @chan:
+ * @event:
+ */
+static void netdev_dma_event(struct dma_client *client, struct dma_chan *chan,
+       enum dma_event event)
+{
+       spin_lock(&net_dma_event_lock);
+       switch (event) {
+       case DMA_RESOURCE_ADDED:
+               net_dma_count++;
+               net_dma_rebalance();
+               break;
+       case DMA_RESOURCE_REMOVED:
+               net_dma_count--;
+               net_dma_rebalance();
+               break;
+       default:
+               break;
+       }
+       spin_unlock(&net_dma_event_lock);
+}
+
+/**
+ * netdev_dma_regiser - register the networking subsystem as a DMA client
+ */
+static int __init netdev_dma_register(void)
+{
+       spin_lock_init(&net_dma_event_lock);
+       net_dma_client = dma_async_client_register(netdev_dma_event);
+       if (net_dma_client == NULL)
+               return -ENOMEM;
+
+       dma_async_client_chan_request(net_dma_client, num_online_cpus());
+       return 0;
+}
+
+#else
+static int __init netdev_dma_register(void) { return -ENODEV; }
+#endif /* CONFIG_NET_DMA */
 
 /*
  *     Initialize the DEV module. At boot time this walks the device list and
@@ -3353,6 +3395,8 @@ static int __init net_dev_init(void)
                atomic_set(&queue->backlog_dev.refcnt, 1);
        }
 
+       netdev_dma_register();
+
        dev_boot_phase = 0;
 
        open_softirq(NET_TX_SOFTIRQ, net_tx_action, NULL);
@@ -3371,7 +3415,6 @@ subsys_initcall(net_dev_init);
 EXPORT_SYMBOL(__dev_get_by_index);
 EXPORT_SYMBOL(__dev_get_by_name);
 EXPORT_SYMBOL(__dev_remove_pack);
-EXPORT_SYMBOL(__skb_linearize);
 EXPORT_SYMBOL(dev_valid_name);
 EXPORT_SYMBOL(dev_add_pack);
 EXPORT_SYMBOL(dev_alloc_name);