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path: root/drivers/net/xen-netback/rx.c
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Diffstat (limited to 'drivers/net/xen-netback/rx.c')
-rw-r--r--drivers/net/xen-netback/rx.c77
1 files changed, 49 insertions, 28 deletions
diff --git a/drivers/net/xen-netback/rx.c b/drivers/net/xen-netback/rx.c
index accc991d153f..dbac4c03d21a 100644
--- a/drivers/net/xen-netback/rx.c
+++ b/drivers/net/xen-netback/rx.c
@@ -33,28 +33,36 @@
#include <xen/xen.h>
#include <xen/events.h>
-static bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue)
+/*
+ * 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)
{
- RING_IDX prod, cons;
- struct sk_buff *skb;
- int needed;
- unsigned long flags;
-
- spin_lock_irqsave(&queue->rx_queue.lock, flags);
+ unsigned int needed = 0;
- skb = skb_peek(&queue->rx_queue);
- if (!skb) {
- spin_unlock_irqrestore(&queue->rx_queue.lock, flags);
- return false;
+ if (skb) {
+ needed = DIV_ROUND_UP(skb->len, XEN_PAGE_SIZE);
+ if (skb_is_gso(skb))
+ needed++;
+ if (skb->sw_hash)
+ needed++;
}
- 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);
+}
- spin_unlock_irqrestore(&queue->rx_queue.lock, flags);
+static bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue)
+{
+ RING_IDX prod, cons;
+ unsigned int needed;
+
+ needed = READ_ONCE(queue->rx_slots_needed);
+ if (!needed)
+ return false;
do {
prod = queue->rx.sring->req_prod;
@@ -80,13 +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);
@@ -100,6 +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;
@@ -134,6 +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++;
}
}
@@ -487,27 +504,31 @@ 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;
-
- prod = queue->rx.sring->req_prod;
- cons = queue->rx.req_cons;
+ unsigned int needed = READ_ONCE(queue->rx_slots_needed);
- return queue->stalled && prod - cons >= 1;
+ return queue->stalled && xenvif_rx_queue_slots(queue) >= needed;
}
bool xenvif_have_rx_work(struct xenvif_queue *queue, bool test_kthread)