diff options
Diffstat (limited to 'drivers/net/xen-netback/netback.c')
-rw-r--r-- | drivers/net/xen-netback/netback.c | 110 |
1 files changed, 95 insertions, 15 deletions
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index c65b636..aa20933 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, @@ -1953,26 +2025,23 @@ int xenvif_kthread_guest_rx(void *data) * context so we defer it here, if this thread is * associated with queue 0. */ - if (unlikely(queue->vif->disabled && netif_carrier_ok(queue->vif->dev) && queue->id == 0)) + 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(); } @@ -2027,6 +2096,13 @@ static int __init netback_init(void) rx_drain_timeout_jiffies = msecs_to_jiffies(rx_drain_timeout_msecs); +#ifdef CONFIG_DEBUG_FS + xen_netback_dbg_root = debugfs_create_dir("xen-netback", NULL); + if (IS_ERR_OR_NULL(xen_netback_dbg_root)) + pr_warn("Init of debugfs returned %ld!\n", + PTR_ERR(xen_netback_dbg_root)); +#endif /* CONFIG_DEBUG_FS */ + return 0; failed_init: @@ -2037,6 +2113,10 @@ module_init(netback_init); static void __exit netback_fini(void) { +#ifdef CONFIG_DEBUG_FS + if (!IS_ERR_OR_NULL(xen_netback_dbg_root)) + debugfs_remove_recursive(xen_netback_dbg_root); +#endif /* CONFIG_DEBUG_FS */ xenvif_xenbus_fini(); } module_exit(netback_fini); |