sunvnet: Schedule maybe_tx_wakeup() as a tasklet from ldc_rx path
At the tail of vnet_event(), if we hit the maybe_tx_wakeup()
condition, we try to take the netif_tx_lock() in the
recv-interrupt-context and can deadlock with dev_watchdog().
vnet_event() should schedule maybe_tx_wakeup() as a tasklet
to avoid this deadlock
Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/sun/sunvnet.c b/drivers/net/ethernet/sun/sunvnet.c
index a587179..23c89ab 100644
--- a/drivers/net/ethernet/sun/sunvnet.c
+++ b/drivers/net/ethernet/sun/sunvnet.c
@@ -488,8 +488,9 @@
return 0;
}
-static void maybe_tx_wakeup(struct vnet *vp)
+static void maybe_tx_wakeup(unsigned long param)
{
+ struct vnet *vp = (struct vnet *)param;
struct net_device *dev = vp->dev;
netif_tx_lock(dev);
@@ -586,8 +587,13 @@
break;
}
spin_unlock(&vio->lock);
+ /* Kick off a tasklet to wake the queue. We cannot call
+ * maybe_tx_wakeup directly here because we could deadlock on
+ * netif_tx_lock() with dev_watchdog()
+ */
if (unlikely(tx_wakeup && err != -ECONNRESET))
- maybe_tx_wakeup(port->vp);
+ tasklet_schedule(&port->vp->vnet_tx_wakeup);
+
local_irq_restore(flags);
}
@@ -1070,6 +1076,7 @@
vp = netdev_priv(dev);
spin_lock_init(&vp->lock);
+ tasklet_init(&vp->vnet_tx_wakeup, maybe_tx_wakeup, (unsigned long)vp);
vp->dev = dev;
INIT_LIST_HEAD(&vp->port_list);
@@ -1129,6 +1136,7 @@
vp = list_first_entry(&vnet_list, struct vnet, list);
list_del(&vp->list);
dev = vp->dev;
+ tasklet_kill(&vp->vnet_tx_wakeup);
/* vio_unregister_driver() should have cleaned up port_list */
BUG_ON(!list_empty(&vp->port_list));
unregister_netdev(dev);