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path: root/drivers/net/xen-netback/netback.c
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Diffstat (limited to 'drivers/net/xen-netback/netback.c')
-rw-r--r--drivers/net/xen-netback/netback.c97
1 files changed, 83 insertions, 14 deletions
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 6c4cc0f44da5..aa2093325be1 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -1869,8 +1869,7 @@ void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx)
static inline int rx_work_todo(struct xenvif_queue *queue)
{
return (!skb_queue_empty(&queue->rx_queue) &&
- xenvif_rx_ring_slots_available(queue, queue->rx_last_skb_slots)) ||
- queue->rx_queue_purge;
+ xenvif_rx_ring_slots_available(queue, queue->rx_last_skb_slots));
}
static inline int tx_work_todo(struct xenvif_queue *queue)
@@ -1935,6 +1934,75 @@ static void xenvif_start_queue(struct xenvif_queue *queue)
xenvif_wake_queue(queue);
}
+/* Only called from the queue's thread, it handles the situation when the guest
+ * doesn't post enough requests on the receiving ring.
+ * First xenvif_start_xmit disables QDisc and start a timer, and then either the
+ * timer fires, or the guest send an interrupt after posting new request. If it
+ * is the timer, the carrier is turned off here.
+ * */
+static void xenvif_rx_purge_event(struct xenvif_queue *queue)
+{
+ /* Either the last unsuccesful skb or at least 1 slot should fit */
+ int needed = queue->rx_last_skb_slots ?
+ queue->rx_last_skb_slots : 1;
+
+ /* It is assumed that if the guest post new slots after this, the RX
+ * interrupt will set the QUEUE_STATUS_RX_PURGE_EVENT bit and wake up
+ * the thread again
+ */
+ set_bit(QUEUE_STATUS_RX_STALLED, &queue->status);
+ if (!xenvif_rx_ring_slots_available(queue, needed)) {
+ rtnl_lock();
+ if (netif_carrier_ok(queue->vif->dev)) {
+ /* Timer fired and there are still no slots. Turn off
+ * everything except the interrupts
+ */
+ netif_carrier_off(queue->vif->dev);
+ skb_queue_purge(&queue->rx_queue);
+ queue->rx_last_skb_slots = 0;
+ if (net_ratelimit())
+ netdev_err(queue->vif->dev, "Carrier off due to lack of guest response on queue %d\n", queue->id);
+ } else {
+ /* Probably an another queue already turned the carrier
+ * off, make sure nothing is stucked in the internal
+ * queue of this queue
+ */
+ skb_queue_purge(&queue->rx_queue);
+ queue->rx_last_skb_slots = 0;
+ }
+ rtnl_unlock();
+ } else if (!netif_carrier_ok(queue->vif->dev)) {
+ unsigned int num_queues = queue->vif->num_queues;
+ unsigned int i;
+ /* The carrier was down, but an interrupt kicked
+ * the thread again after new requests were
+ * posted
+ */
+ clear_bit(QUEUE_STATUS_RX_STALLED,
+ &queue->status);
+ rtnl_lock();
+ netif_carrier_on(queue->vif->dev);
+ netif_tx_wake_all_queues(queue->vif->dev);
+ rtnl_unlock();
+
+ for (i = 0; i < num_queues; i++) {
+ struct xenvif_queue *temp = &queue->vif->queues[i];
+
+ xenvif_napi_schedule_or_enable_events(temp);
+ }
+ if (net_ratelimit())
+ netdev_err(queue->vif->dev, "Carrier on again\n");
+ } else {
+ /* Queuing were stopped, but the guest posted
+ * new requests and sent an interrupt
+ */
+ clear_bit(QUEUE_STATUS_RX_STALLED,
+ &queue->status);
+ del_timer_sync(&queue->rx_stalled);
+ xenvif_start_queue(queue);
+ }
+}
+
int xenvif_kthread_guest_rx(void *data)
{
struct xenvif_queue *queue = data;
@@ -1944,8 +2012,12 @@ int xenvif_kthread_guest_rx(void *data)
wait_event_interruptible(queue->wq,
rx_work_todo(queue) ||
queue->vif->disabled ||
+ test_bit(QUEUE_STATUS_RX_PURGE_EVENT, &queue->status) ||
kthread_should_stop());
+ if (kthread_should_stop())
+ break;
+
/* This frontend is found to be rogue, disable it in
* kthread context. Currently this is only set when
* netback finds out frontend sends malformed packet,
@@ -1955,24 +2027,21 @@ int xenvif_kthread_guest_rx(void *data)
*/
if (unlikely(queue->vif->disabled && queue->id == 0))
xenvif_carrier_off(queue->vif);
-
- if (kthread_should_stop())
- break;
-
- if (queue->rx_queue_purge) {
+ else if (unlikely(test_and_clear_bit(QUEUE_STATUS_RX_PURGE_EVENT,
+ &queue->status))) {
+ xenvif_rx_purge_event(queue);
+ } else if (!netif_carrier_ok(queue->vif->dev)) {
+ /* Another queue stalled and turned the carrier off, so
+ * purge the internal queue of queues which were not
+ * blocked
+ */
skb_queue_purge(&queue->rx_queue);
- queue->rx_queue_purge = false;
+ queue->rx_last_skb_slots = 0;
}
if (!skb_queue_empty(&queue->rx_queue))
xenvif_rx_action(queue);
- if (skb_queue_empty(&queue->rx_queue) &&
- xenvif_queue_stopped(queue)) {
- del_timer_sync(&queue->wake_queue);
- xenvif_start_queue(queue);
- }
-
cond_resched();
}