xen-netback: clear vif->task on disconnect
xenvif_start_xmit() relies on checking vif->task for NULL to determine
whether the vif is ready to accept packets. The task thread is stopped in
xenvif_disconnect() but task is not set to NULL. Thus, on a re-connect the
check will give a false positive.
Also since commit ea732dff5cfa10789007bf4a5b935388a0bb2a8f (Handle backend
state transitions in a more robust way) it should not be possible for
xenvif_connect() to be called if the vif is already connected so change the
check of vif->tx_irq to a BUG_ON() and also add a BUG_ON(vif->task).
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index 2329ccc..870f1fa 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -368,11 +368,11 @@
unsigned long rx_ring_ref, unsigned int tx_evtchn,
unsigned int rx_evtchn)
{
+ struct task_struct *task;
int err = -ENOMEM;
- /* Already connected through? */
- if (vif->tx_irq)
- return 0;
+ BUG_ON(vif->tx_irq);
+ BUG_ON(vif->task);
err = xenvif_map_frontend_rings(vif, tx_ring_ref, rx_ring_ref);
if (err < 0)
@@ -411,14 +411,16 @@
}
init_waitqueue_head(&vif->wq);
- vif->task = kthread_create(xenvif_kthread,
- (void *)vif, "%s", vif->dev->name);
- if (IS_ERR(vif->task)) {
+ task = kthread_create(xenvif_kthread,
+ (void *)vif, "%s", vif->dev->name);
+ if (IS_ERR(task)) {
pr_warn("Could not allocate kthread for %s\n", vif->dev->name);
- err = PTR_ERR(vif->task);
+ err = PTR_ERR(task);
goto err_rx_unbind;
}
+ vif->task = task;
+
rtnl_lock();
if (!vif->can_sg && vif->dev->mtu > ETH_DATA_LEN)
dev_set_mtu(vif->dev, ETH_DATA_LEN);
@@ -461,8 +463,10 @@
if (netif_carrier_ok(vif->dev))
xenvif_carrier_off(vif);
- if (vif->task)
+ if (vif->task) {
kthread_stop(vif->task);
+ vif->task = NULL;
+ }
if (vif->tx_irq) {
if (vif->tx_irq == vif->rx_irq)