diff options
Diffstat (limited to 'drivers/net/xen-netback/rx.c')
-rw-r--r-- | drivers/net/xen-netback/rx.c | 83 |
1 files changed, 58 insertions, 25 deletions
diff --git a/drivers/net/xen-netback/rx.c b/drivers/net/xen-netback/rx.c index b1cf7c6f407a..29c7645f5780 100644 --- a/drivers/net/xen-netback/rx.c +++ b/drivers/net/xen-netback/rx.c @@ -33,22 +33,37 @@ #include <xen/xen.h> #include <xen/events.h> +/* + * Update the needed ring page slots for the first SKB queued. + * Note that any call sequence outside the RX thread calling this function + * needs to wake up the RX thread via a call of xenvif_kick_thread() + * afterwards in order to avoid a race with putting the thread to sleep. + */ +static void xenvif_update_needed_slots(struct xenvif_queue *queue, + const struct sk_buff *skb) +{ + unsigned int needed = 0; + + if (skb) { + needed = DIV_ROUND_UP(skb->len, XEN_PAGE_SIZE); + if (skb_is_gso(skb)) + needed++; + if (skb->sw_hash) + needed++; + } + + WRITE_ONCE(queue->rx_slots_needed, needed); +} + static bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue) { RING_IDX prod, cons; - struct sk_buff *skb; - int needed; + unsigned int needed; - skb = skb_peek(&queue->rx_queue); - if (!skb) + needed = READ_ONCE(queue->rx_slots_needed); + if (!needed) return false; - needed = DIV_ROUND_UP(skb->len, XEN_PAGE_SIZE); - if (skb_is_gso(skb)) - needed++; - if (skb->sw_hash) - needed++; - do { prod = queue->rx.sring->req_prod; cons = queue->rx.req_cons; @@ -73,13 +88,19 @@ void xenvif_rx_queue_tail(struct xenvif_queue *queue, struct sk_buff *skb) spin_lock_irqsave(&queue->rx_queue.lock, flags); - __skb_queue_tail(&queue->rx_queue, skb); - - queue->rx_queue_len += skb->len; - if (queue->rx_queue_len > queue->rx_queue_max) { + if (queue->rx_queue_len >= queue->rx_queue_max) { struct net_device *dev = queue->vif->dev; netif_tx_stop_queue(netdev_get_tx_queue(dev, queue->id)); + kfree_skb(skb); + queue->vif->dev->stats.rx_dropped++; + } else { + if (skb_queue_empty(&queue->rx_queue)) + xenvif_update_needed_slots(queue, skb); + + __skb_queue_tail(&queue->rx_queue, skb); + + queue->rx_queue_len += skb->len; } spin_unlock_irqrestore(&queue->rx_queue.lock, flags); @@ -93,6 +114,8 @@ static struct sk_buff *xenvif_rx_dequeue(struct xenvif_queue *queue) skb = __skb_dequeue(&queue->rx_queue); if (skb) { + xenvif_update_needed_slots(queue, skb_peek(&queue->rx_queue)); + queue->rx_queue_len -= skb->len; if (queue->rx_queue_len < queue->rx_queue_max) { struct netdev_queue *txq; @@ -127,6 +150,7 @@ static void xenvif_rx_queue_drop_expired(struct xenvif_queue *queue) break; xenvif_rx_dequeue(queue); kfree_skb(skb); + queue->vif->dev->stats.rx_dropped++; } } @@ -467,36 +491,40 @@ void xenvif_rx_action(struct xenvif_queue *queue) xenvif_rx_copy_flush(queue); } -static bool xenvif_rx_queue_stalled(struct xenvif_queue *queue) +static RING_IDX xenvif_rx_queue_slots(const struct xenvif_queue *queue) { RING_IDX prod, cons; prod = queue->rx.sring->req_prod; cons = queue->rx.req_cons; + return prod - cons; +} + +static bool xenvif_rx_queue_stalled(const struct xenvif_queue *queue) +{ + unsigned int needed = READ_ONCE(queue->rx_slots_needed); + return !queue->stalled && - prod - cons < 1 && + xenvif_rx_queue_slots(queue) < needed && time_after(jiffies, queue->last_rx_time + queue->vif->stall_timeout); } static bool xenvif_rx_queue_ready(struct xenvif_queue *queue) { - RING_IDX prod, cons; + unsigned int needed = READ_ONCE(queue->rx_slots_needed); - prod = queue->rx.sring->req_prod; - cons = queue->rx.req_cons; - - return queue->stalled && prod - cons >= 1; + return queue->stalled && xenvif_rx_queue_slots(queue) >= needed; } -static bool xenvif_have_rx_work(struct xenvif_queue *queue) +bool xenvif_have_rx_work(struct xenvif_queue *queue, bool test_kthread) { return xenvif_rx_ring_slots_available(queue) || (queue->vif->stall_timeout && (xenvif_rx_queue_stalled(queue) || xenvif_rx_queue_ready(queue))) || - kthread_should_stop() || + (test_kthread && kthread_should_stop()) || queue->vif->disabled; } @@ -527,15 +555,20 @@ static void xenvif_wait_for_rx_work(struct xenvif_queue *queue) { DEFINE_WAIT(wait); - if (xenvif_have_rx_work(queue)) + if (xenvif_have_rx_work(queue, true)) return; for (;;) { long ret; prepare_to_wait(&queue->wq, &wait, TASK_INTERRUPTIBLE); - if (xenvif_have_rx_work(queue)) + if (xenvif_have_rx_work(queue, true)) break; + if (atomic_fetch_andnot(NETBK_RX_EOI | NETBK_COMMON_EOI, + &queue->eoi_pending) & + (NETBK_RX_EOI | NETBK_COMMON_EOI)) + xen_irq_lateeoi(queue->rx_irq, 0); + ret = schedule_timeout(xenvif_rx_queue_timeout(queue)); if (!ret) break; |