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authorPaul Durrant <Paul.Durrant@citrix.com>2013-12-03 14:06:25 +0000
committerDavid S. Miller <davem@davemloft.net>2013-12-03 11:49:30 -0500
commit67fa36609fe0a0a4b4c99120e5093599556e4c5b (patch)
tree4c607aeaa3de8da2b7b3de8d2457195c643281cb
parent7ce5a27f2ef8ed4f8f892f46391f933c0e2ac0f1 (diff)
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>
-rw-r--r--drivers/net/xen-netback/interface.c20
1 files changed, 12 insertions, 8 deletions
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index 2329cccf1fa..870f1fa5837 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -368,11 +368,11 @@ int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
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 @@ int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
}
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 @@ void xenvif_disconnect(struct xenvif *vif)
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)