net: Add ops->ndo_xmit_flush()

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

1 files changed, 35 insertions, 0 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index eb73444e1bd0..220c50984688 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -782,6 +782,19 @@ typedef u16 (*select_queue_fallback_t)(struct net_device *dev,
  *        (can also return NETDEV_TX_LOCKED iff NETIF_F_LLTX)
  *      Required can not be NULL.
  *
+ * void (*ndo_xmit_flush)(struct net_device *dev, u16 queue);
+ *      A driver implements this function when it wishes to support
+ *      deferred TX queue flushing.  The idea is that the expensive
+ *      operation to trigger TX queue processing can be done after
+ *      N calls to ndo_start_xmit rather than being done every single
+ *      time.  In this regime ndo_start_xmit will be called one or more
+ *      times, and then a final ndo_xmit_flush call will be made to
+ *      have the driver tell the device about the new pending TX queue
+ *      entries.  The kernel keeps track of which queues need flushing
+ *      by monitoring skb->queue_mapping of the packets it submits to
+ *      ndo_start_xmit.  This is the queue value that will be passed
+ *      to ndo_xmit_flush.
+ *
  * u16 (*ndo_select_queue)(struct net_device *dev, struct sk_buff *skb,
  *                         void *accel_priv, select_queue_fallback_t fallback);
  *      Called to decide which queue to when device supports multiple
@@ -1005,6 +1018,7 @@ struct net_device_ops {
         int                     (*ndo_stop)(struct net_device *dev);
         netdev_tx_t             (*ndo_start_xmit) (struct sk_buff *skb,
                                                    struct net_device *dev);
+        void                    (*ndo_xmit_flush)(struct net_device *dev, u16 queue);
         u16                     (*ndo_select_queue)(struct net_device *dev,
                                                     struct sk_buff *skb,
                                                     void *accel_priv,
@@ -3430,6 +3444,27 @@ int __init dev_proc_init(void);
 #define dev_proc_init() 0
 #endif
 
+static inline netdev_tx_t __netdev_start_xmit(const struct net_device_ops *ops,
+                                              struct sk_buff *skb, struct net_device *dev)
+{
+        netdev_tx_t ret;
+        u16 q;
+
+        q = skb->queue_mapping;
+        ret = ops->ndo_start_xmit(skb, dev);
+        if (dev_xmit_complete(ret) && ops->ndo_xmit_flush)
+                ops->ndo_xmit_flush(dev, q);
+
+        return ret;
+}
+
+static inline netdev_tx_t netdev_start_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+        const struct net_device_ops *ops = dev->netdev_ops;
+
+        return __netdev_start_xmit(ops, skb, dev);
+}
+
 int netdev_class_create_file_ns(struct class_attribute *class_attr,
                                 const void *ns);
 void netdev_class_remove_file_ns(struct class_attribute *class_attr,