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path: root/drivers/net/ntb_netdev.c
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Diffstat (limited to 'drivers/net/ntb_netdev.c')
-rw-r--r--drivers/net/ntb_netdev.c77
1 files changed, 77 insertions, 0 deletions
diff --git a/drivers/net/ntb_netdev.c b/drivers/net/ntb_netdev.c
index d8757bf9ad75..a9acf7156855 100644
--- a/drivers/net/ntb_netdev.c
+++ b/drivers/net/ntb_netdev.c
@@ -61,11 +61,21 @@ MODULE_VERSION(NTB_NETDEV_VER);
MODULE_LICENSE("Dual BSD/GPL");
MODULE_AUTHOR("Intel Corporation");
+/* Time in usecs for tx resource reaper */
+static unsigned int tx_time = 1;
+
+/* Number of descriptors to free before resuming tx */
+static unsigned int tx_start = 10;
+
+/* Number of descriptors still available before stop upper layer tx */
+static unsigned int tx_stop = 5;
+
struct ntb_netdev {
struct list_head list;
struct pci_dev *pdev;
struct net_device *ndev;
struct ntb_transport_qp *qp;
+ struct timer_list tx_timer;
};
#define NTB_TX_TIMEOUT_MS 1000
@@ -136,11 +146,42 @@ enqueue_again:
}
}
+static int __ntb_netdev_maybe_stop_tx(struct net_device *netdev,
+ struct ntb_transport_qp *qp, int size)
+{
+ struct ntb_netdev *dev = netdev_priv(netdev);
+
+ netif_stop_queue(netdev);
+ /* Make sure to see the latest value of ntb_transport_tx_free_entry()
+ * since the queue was last started.
+ */
+ smp_mb();
+
+ if (likely(ntb_transport_tx_free_entry(qp) < size)) {
+ mod_timer(&dev->tx_timer, jiffies + usecs_to_jiffies(tx_time));
+ return -EBUSY;
+ }
+
+ netif_start_queue(netdev);
+ return 0;
+}
+
+static int ntb_netdev_maybe_stop_tx(struct net_device *ndev,
+ struct ntb_transport_qp *qp, int size)
+{
+ if (netif_queue_stopped(ndev) ||
+ (ntb_transport_tx_free_entry(qp) >= size))
+ return 0;
+
+ return __ntb_netdev_maybe_stop_tx(ndev, qp, size);
+}
+
static void ntb_netdev_tx_handler(struct ntb_transport_qp *qp, void *qp_data,
void *data, int len)
{
struct net_device *ndev = qp_data;
struct sk_buff *skb;
+ struct ntb_netdev *dev = netdev_priv(ndev);
skb = data;
if (!skb || !ndev)
@@ -155,6 +196,15 @@ static void ntb_netdev_tx_handler(struct ntb_transport_qp *qp, void *qp_data,
}
dev_kfree_skb(skb);
+
+ if (ntb_transport_tx_free_entry(dev->qp) >= tx_start) {
+ /* Make sure anybody stopping the queue after this sees the new
+ * value of ntb_transport_tx_free_entry()
+ */
+ smp_mb();
+ if (netif_queue_stopped(ndev))
+ netif_wake_queue(ndev);
+ }
}
static netdev_tx_t ntb_netdev_start_xmit(struct sk_buff *skb,
@@ -163,10 +213,15 @@ static netdev_tx_t ntb_netdev_start_xmit(struct sk_buff *skb,
struct ntb_netdev *dev = netdev_priv(ndev);
int rc;
+ ntb_netdev_maybe_stop_tx(ndev, dev->qp, tx_stop);
+
rc = ntb_transport_tx_enqueue(dev->qp, skb, skb->data, skb->len);
if (rc)
goto err;
+ /* check for next submit */
+ ntb_netdev_maybe_stop_tx(ndev, dev->qp, tx_stop);
+
return NETDEV_TX_OK;
err:
@@ -175,6 +230,23 @@ err:
return NETDEV_TX_BUSY;
}
+static void ntb_netdev_tx_timer(unsigned long data)
+{
+ struct net_device *ndev = (struct net_device *)data;
+ struct ntb_netdev *dev = netdev_priv(ndev);
+
+ if (ntb_transport_tx_free_entry(dev->qp) < tx_stop) {
+ mod_timer(&dev->tx_timer, jiffies + msecs_to_jiffies(tx_time));
+ } else {
+ /* Make sure anybody stopping the queue after this sees the new
+ * value of ntb_transport_tx_free_entry()
+ */
+ smp_mb();
+ if (netif_queue_stopped(ndev))
+ netif_wake_queue(ndev);
+ }
+}
+
static int ntb_netdev_open(struct net_device *ndev)
{
struct ntb_netdev *dev = netdev_priv(ndev);
@@ -197,8 +269,11 @@ static int ntb_netdev_open(struct net_device *ndev)
}
}
+ setup_timer(&dev->tx_timer, ntb_netdev_tx_timer, (unsigned long)ndev);
+
netif_carrier_off(ndev);
ntb_transport_link_up(dev->qp);
+ netif_start_queue(ndev);
return 0;
@@ -219,6 +294,8 @@ static int ntb_netdev_close(struct net_device *ndev)
while ((skb = ntb_transport_rx_remove(dev->qp, &len)))
dev_kfree_skb(skb);
+ del_timer_sync(&dev->tx_timer);
+
return 0;
}