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synced 2024-08-21 08:19:28 +00:00
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>
This commit is contained in:
parent
8892475386
commit
e1f00a69ec
4 changed files with 124 additions and 29 deletions
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@ -57,8 +57,12 @@ struct xenvif {
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u8 fe_dev_addr[6];
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/* Physical parameters of the comms window. */
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unsigned int irq;
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/* When feature-split-event-channels = 0, tx_irq = rx_irq. */
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unsigned int tx_irq;
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unsigned int rx_irq;
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/* Only used when feature-split-event-channels = 1 */
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char tx_irq_name[IFNAMSIZ+4]; /* DEVNAME-tx */
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char rx_irq_name[IFNAMSIZ+4]; /* DEVNAME-rx */
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/* List of frontends to notify after a batch of frames sent. */
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struct list_head notify_list;
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@ -113,7 +117,8 @@ struct xenvif *xenvif_alloc(struct device *parent,
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unsigned int handle);
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int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
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unsigned long rx_ring_ref, unsigned int evtchn);
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unsigned long rx_ring_ref, unsigned int tx_evtchn,
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unsigned int rx_evtchn);
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void xenvif_disconnect(struct xenvif *vif);
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void xenvif_get(struct xenvif *vif);
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@ -158,4 +163,6 @@ void xenvif_carrier_off(struct xenvif *vif);
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/* Returns number of ring slots required to send an skb to the frontend */
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unsigned int xen_netbk_count_skb_slots(struct xenvif *vif, struct sk_buff *skb);
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extern bool separate_tx_rx_irq;
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#endif /* __XEN_NETBACK__COMMON_H__ */
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@ -60,21 +60,39 @@ static int xenvif_rx_schedulable(struct xenvif *vif)
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return xenvif_schedulable(vif) && !xen_netbk_rx_ring_full(vif);
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}
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static irqreturn_t xenvif_interrupt(int irq, void *dev_id)
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static irqreturn_t xenvif_tx_interrupt(int irq, void *dev_id)
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{
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struct xenvif *vif = dev_id;
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if (vif->netbk == NULL)
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return IRQ_NONE;
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return IRQ_HANDLED;
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xen_netbk_schedule_xenvif(vif);
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return IRQ_HANDLED;
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}
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static irqreturn_t xenvif_rx_interrupt(int irq, void *dev_id)
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{
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struct xenvif *vif = dev_id;
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if (vif->netbk == NULL)
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return IRQ_HANDLED;
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if (xenvif_rx_schedulable(vif))
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netif_wake_queue(vif->dev);
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return IRQ_HANDLED;
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}
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static irqreturn_t xenvif_interrupt(int irq, void *dev_id)
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{
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xenvif_tx_interrupt(irq, dev_id);
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xenvif_rx_interrupt(irq, dev_id);
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return IRQ_HANDLED;
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}
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static int xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev)
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{
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struct xenvif *vif = netdev_priv(dev);
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@ -125,13 +143,17 @@ static struct net_device_stats *xenvif_get_stats(struct net_device *dev)
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static void xenvif_up(struct xenvif *vif)
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{
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xen_netbk_add_xenvif(vif);
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enable_irq(vif->irq);
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enable_irq(vif->tx_irq);
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if (vif->tx_irq != vif->rx_irq)
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enable_irq(vif->rx_irq);
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xen_netbk_check_rx_xenvif(vif);
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}
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static void xenvif_down(struct xenvif *vif)
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{
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disable_irq(vif->irq);
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disable_irq(vif->tx_irq);
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if (vif->tx_irq != vif->rx_irq)
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disable_irq(vif->rx_irq);
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del_timer_sync(&vif->credit_timeout);
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xen_netbk_deschedule_xenvif(vif);
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xen_netbk_remove_xenvif(vif);
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@ -308,12 +330,13 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
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}
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int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
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unsigned long rx_ring_ref, unsigned int evtchn)
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unsigned long rx_ring_ref, unsigned int tx_evtchn,
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unsigned int rx_evtchn)
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{
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int err = -ENOMEM;
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/* Already connected through? */
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if (vif->irq)
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if (vif->tx_irq)
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return 0;
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__module_get(THIS_MODULE);
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@ -322,13 +345,37 @@ int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
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if (err < 0)
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goto err;
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err = bind_interdomain_evtchn_to_irqhandler(
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vif->domid, evtchn, xenvif_interrupt, 0,
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vif->dev->name, vif);
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if (err < 0)
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goto err_unmap;
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vif->irq = err;
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disable_irq(vif->irq);
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if (tx_evtchn == rx_evtchn) {
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/* feature-split-event-channels == 0 */
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err = bind_interdomain_evtchn_to_irqhandler(
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vif->domid, tx_evtchn, xenvif_interrupt, 0,
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vif->dev->name, vif);
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if (err < 0)
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goto err_unmap;
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vif->tx_irq = vif->rx_irq = err;
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disable_irq(vif->tx_irq);
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} else {
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/* feature-split-event-channels == 1 */
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snprintf(vif->tx_irq_name, sizeof(vif->tx_irq_name),
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"%s-tx", vif->dev->name);
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err = bind_interdomain_evtchn_to_irqhandler(
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vif->domid, tx_evtchn, xenvif_tx_interrupt, 0,
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vif->tx_irq_name, vif);
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if (err < 0)
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goto err_unmap;
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vif->tx_irq = err;
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disable_irq(vif->tx_irq);
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snprintf(vif->rx_irq_name, sizeof(vif->rx_irq_name),
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"%s-rx", vif->dev->name);
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err = bind_interdomain_evtchn_to_irqhandler(
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vif->domid, rx_evtchn, xenvif_rx_interrupt, 0,
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vif->rx_irq_name, vif);
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if (err < 0)
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goto err_tx_unbind;
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vif->rx_irq = err;
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disable_irq(vif->rx_irq);
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}
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xenvif_get(vif);
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@ -342,6 +389,9 @@ int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
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rtnl_unlock();
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return 0;
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err_tx_unbind:
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unbind_from_irqhandler(vif->tx_irq, vif);
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vif->tx_irq = 0;
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err_unmap:
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xen_netbk_unmap_frontend_rings(vif);
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err:
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@ -375,8 +425,13 @@ void xenvif_disconnect(struct xenvif *vif)
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atomic_dec(&vif->refcnt);
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wait_event(vif->waiting_to_free, atomic_read(&vif->refcnt) == 0);
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if (vif->irq) {
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unbind_from_irqhandler(vif->irq, vif);
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if (vif->tx_irq) {
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if (vif->tx_irq == vif->rx_irq)
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unbind_from_irqhandler(vif->tx_irq, vif);
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else {
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unbind_from_irqhandler(vif->tx_irq, vif);
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unbind_from_irqhandler(vif->rx_irq, vif);
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}
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/* vif->irq is valid, we had a module_get in
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* xenvif_connect.
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*/
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@ -47,6 +47,13 @@
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#include <asm/xen/hypercall.h>
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#include <asm/xen/page.h>
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/* Provide an option to disable split event channels at load time as
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* event channels are limited resource. Split event channels are
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* enabled by default.
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*/
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bool separate_tx_rx_irq = 1;
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module_param(separate_tx_rx_irq, bool, 0644);
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/*
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* This is the maximum slots a skb can have. If a guest sends a skb
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* which exceeds this limit it is considered malicious.
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@ -662,7 +669,7 @@ static void xen_netbk_rx_action(struct xen_netbk *netbk)
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{
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struct xenvif *vif = NULL, *tmp;
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s8 status;
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u16 irq, flags;
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u16 flags;
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struct xen_netif_rx_response *resp;
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struct sk_buff_head rxq;
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struct sk_buff *skb;
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@ -771,7 +778,6 @@ static void xen_netbk_rx_action(struct xen_netbk *netbk)
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sco->meta_slots_used);
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RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->rx, ret);
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irq = vif->irq;
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if (ret && list_empty(&vif->notify_list))
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list_add_tail(&vif->notify_list, ¬ify);
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@ -783,7 +789,7 @@ static void xen_netbk_rx_action(struct xen_netbk *netbk)
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}
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list_for_each_entry_safe(vif, tmp, ¬ify, notify_list) {
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notify_remote_via_irq(vif->irq);
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notify_remote_via_irq(vif->rx_irq);
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list_del_init(&vif->notify_list);
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}
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@ -1762,7 +1768,7 @@ static void make_tx_response(struct xenvif *vif,
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vif->tx.rsp_prod_pvt = ++i;
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RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->tx, notify);
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if (notify)
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notify_remote_via_irq(vif->irq);
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notify_remote_via_irq(vif->tx_irq);
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}
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static struct xen_netif_rx_response *make_rx_response(struct xenvif *vif,
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@ -122,6 +122,16 @@ static int netback_probe(struct xenbus_device *dev,
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goto fail;
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}
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/*
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* Split event channels support, this is optional so it is not
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* put inside the above loop.
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*/
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err = xenbus_printf(XBT_NIL, dev->nodename,
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"feature-split-event-channels",
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"%u", separate_tx_rx_irq);
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if (err)
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pr_debug("Error writing feature-split-event-channels");
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err = xenbus_switch_state(dev, XenbusStateInitWait);
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if (err)
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goto fail;
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@ -393,21 +403,36 @@ static int connect_rings(struct backend_info *be)
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struct xenvif *vif = be->vif;
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struct xenbus_device *dev = be->dev;
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unsigned long tx_ring_ref, rx_ring_ref;
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unsigned int evtchn, rx_copy;
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unsigned int tx_evtchn, rx_evtchn, rx_copy;
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int err;
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int val;
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err = xenbus_gather(XBT_NIL, dev->otherend,
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"tx-ring-ref", "%lu", &tx_ring_ref,
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"rx-ring-ref", "%lu", &rx_ring_ref,
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"event-channel", "%u", &evtchn, NULL);
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"rx-ring-ref", "%lu", &rx_ring_ref, NULL);
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if (err) {
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xenbus_dev_fatal(dev, err,
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"reading %s/ring-ref and event-channel",
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"reading %s/ring-ref",
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dev->otherend);
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return err;
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}
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/* Try split event channels first, then single event channel. */
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err = xenbus_gather(XBT_NIL, dev->otherend,
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"event-channel-tx", "%u", &tx_evtchn,
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"event-channel-rx", "%u", &rx_evtchn, NULL);
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if (err < 0) {
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err = xenbus_scanf(XBT_NIL, dev->otherend,
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"event-channel", "%u", &tx_evtchn);
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if (err < 0) {
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xenbus_dev_fatal(dev, err,
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"reading %s/event-channel(-tx/rx)",
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dev->otherend);
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return err;
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}
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rx_evtchn = tx_evtchn;
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}
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err = xenbus_scanf(XBT_NIL, dev->otherend, "request-rx-copy", "%u",
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&rx_copy);
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if (err == -ENOENT) {
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vif->csum = !val;
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/* Map the shared frame, irq etc. */
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err = xenvif_connect(vif, tx_ring_ref, rx_ring_ref, evtchn);
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err = xenvif_connect(vif, tx_ring_ref, rx_ring_ref,
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tx_evtchn, rx_evtchn);
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if (err) {
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xenbus_dev_fatal(dev, err,
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"mapping shared-frames %lu/%lu port %u",
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tx_ring_ref, rx_ring_ref, evtchn);
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"mapping shared-frames %lu/%lu port tx %u rx %u",
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tx_ring_ref, rx_ring_ref,
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tx_evtchn, rx_evtchn);
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return err;
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}
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return 0;
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