xen-netback: split event channels support for Xen backend driver

Netback and netfront only use one event channel to do TX / RX notification,
which may cause unnecessary wake-up of processing routines. This patch adds a
new feature called feature-split-event-channels to netback, enabling it to
handle TX and RX events separately.

Netback will use tx_irq to notify guest for TX completion, rx_irq for RX
notification.

If frontend doesn't support this feature, tx_irq equals to rx_irq.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 10 insertions, 3 deletions

diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 6102a6c59f4e..8a4d77ee9c5b 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -57,8 +57,12 @@ struct xenvif {
 
         u8               fe_dev_addr[6];
 
-        /* Physical parameters of the comms window. */
-        unsigned int     irq;
+        /* When feature-split-event-channels = 0, tx_irq = rx_irq. */
+        unsigned int tx_irq;
+        unsigned int rx_irq;
+        /* Only used when feature-split-event-channels = 1 */
+        char tx_irq_name[IFNAMSIZ+4]; /* DEVNAME-tx */
+        char rx_irq_name[IFNAMSIZ+4]; /* DEVNAME-rx */
 
         /* List of frontends to notify after a batch of frames sent. */
         struct list_head notify_list;
@@ -113,7 +117,8 @@ struct xenvif *xenvif_alloc(struct device *parent,
                             unsigned int handle);
 
 int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
-                   unsigned long rx_ring_ref, unsigned int evtchn);
+                   unsigned long rx_ring_ref, unsigned int tx_evtchn,
+                   unsigned int rx_evtchn);
 void xenvif_disconnect(struct xenvif *vif);
 
 void xenvif_get(struct xenvif *vif);
@@ -158,4 +163,6 @@ void xenvif_carrier_off(struct xenvif *vif);
 /* Returns number of ring slots required to send an skb to the frontend */
 unsigned int xen_netbk_count_skb_slots(struct xenvif *vif, struct sk_buff *skb);
 
+extern bool separate_tx_rx_irq;
+
 #endif /* __XEN_NETBACK__COMMON_H__ */