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xen-netback: make feature-rx-notify mandatory 

Frontends that do not provide feature-rx-notify may stall because
netback depends on the notification from frontend to wake the guest Rx
thread (even if can_queue is false).

This could be fixed but feature-rx-notify was introduced in 2006 and I
am not aware of any frontends that do not implement this.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David Vrabel 2014-10-22 14:08:53 +01:00 committed by David S. Miller
parent 5345c1d417
commit bc96f648df
3 changed files with 5 additions and 25 deletions
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5
drivers/net/xen-netback/common.h
View File

@ -228,9 +228,6 @@ struct xenvif {
u8 ip_csum:1;
u8 ipv6_csum:1;
/* Internal feature information. */
u8 can_queue:1; /* can queue packets for receiver? */
/* Is this interface disabled? True when backend discovers
* frontend is rogue.
*/
@ -272,8 +269,6 @@ void xenvif_xenbus_fini(void);
int xenvif_schedulable(struct xenvif *vif);
int xenvif_must_stop_queue(struct xenvif_queue *queue);
int xenvif_queue_stopped(struct xenvif_queue *queue);
void xenvif_wake_queue(struct xenvif_queue *queue);

12
drivers/net/xen-netback/interface.c
View File

@ -60,16 +60,6 @@ void xenvif_skb_zerocopy_complete(struct xenvif_queue *queue)
atomic_dec(&queue->inflight_packets);
}
static inline void xenvif_stop_queue(struct xenvif_queue *queue)
{
struct net_device *dev = queue->vif->dev;
if (!queue->vif->can_queue)
return;
netif_tx_stop_queue(netdev_get_tx_queue(dev, queue->id));
}
int xenvif_schedulable(struct xenvif *vif)
{
return netif_running(vif->dev) &&
@ -209,7 +199,7 @@ static int xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev)
if (!xenvif_rx_ring_slots_available(queue, min_slots_needed)) {
queue->rx_stalled.function = xenvif_rx_stalled;
queue->rx_stalled.data = (unsigned long)queue;
xenvif_stop_queue(queue);
netif_tx_stop_queue(netdev_get_tx_queue(dev, queue->id));
mod_timer(&queue->rx_stalled,
jiffies + rx_drain_timeout_jiffies);
}

13
drivers/net/xen-netback/xenbus.c
View File

@ -873,15 +873,10 @@ static int read_xenbus_vif_flags(struct backend_info *be)
if (!rx_copy)
return -EOPNOTSUPP;
if (vif->dev->tx_queue_len != 0) {
if (xenbus_scanf(XBT_NIL, dev->otherend,
"feature-rx-notify", "%d", &val) < 0)
val = 0;
if (val)
vif->can_queue = 1;
else
/* Must be non-zero for pfifo_fast to work. */
vif->dev->tx_queue_len = 1;
if (xenbus_scanf(XBT_NIL, dev->otherend,
"feature-rx-notify", "%d", &val) < 0 || val == 0) {
xenbus_dev_fatal(dev, -EINVAL, "feature-rx-notify is mandatory");
return -EINVAL;
}
if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-sg",