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net: vrf: Switch dst dev to loopback on device delete

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Attempting to delete a VRF device with a socket bound to it can stall:

  unregister_netdevice: waiting for red to become free. Usage count = 1

The unregister is waiting for the dst to be released and with it
references to the vrf device. Similar to dst_ifdown switch the dst
dev to loopback on delete for all of the dst's for the vrf device
and release the references to the vrf device.

Fixes: 193125dbd8 ("net: Introduce VRF device driver")
Fixes: 35402e3136 ("net: Add IPv6 support to VRF device")
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David Ahern 2016-06-14 11:37:21 -07:00 committed by David S. Miller
parent 042ce72230
commit 810e530bfa
1 changed files with 42 additions and 13 deletions
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55
drivers/net/vrf.c
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@ -378,23 +378,37 @@ static int vrf_output6(struct net *net, struct sock *sk, struct sk_buff *skb)
}
/* holding rtnl */
static void vrf_rt6_release(struct net_vrf *vrf)
static void vrf_rt6_release(struct net_device *dev, struct net_vrf *vrf)
{
struct rt6_info *rt6 = rtnl_dereference(vrf->rt6);
struct rt6_info *rt6_local = rtnl_dereference(vrf->rt6_local);
struct net *net = dev_net(dev);
struct dst_entry *dst;
RCU_INIT_POINTER(vrf->rt6, NULL);
RCU_INIT_POINTER(vrf->rt6_local, NULL);
synchronize_rcu();
if (rt6)
dst_release(&rt6->dst);
/* move dev in dst's to loopback so this VRF device can be deleted
* - based on dst_ifdown
*/
if (rt6) {
dst = &rt6->dst;
dev_put(dst->dev);
dst->dev = net->loopback_dev;
dev_hold(dst->dev);
dst_release(dst);
}
if (rt6_local) {
if (rt6_local->rt6i_idev)
in6_dev_put(rt6_local->rt6i_idev);
dst_release(&rt6_local->dst);
dst = &rt6_local->dst;
dev_put(dst->dev);
dst->dev = net->loopback_dev;
dev_hold(dst->dev);
dst_release(dst);
}
}
@ -449,7 +463,7 @@ out:
return rc;
}
#else
static void vrf_rt6_release(struct net_vrf *vrf)
static void vrf_rt6_release(struct net_device *dev, struct net_vrf *vrf)
{
}
@ -518,20 +532,35 @@ static int vrf_output(struct net *net, struct sock *sk, struct sk_buff *skb)
}
/* holding rtnl */
static void vrf_rtable_release(struct net_vrf *vrf)
static void vrf_rtable_release(struct net_device *dev, struct net_vrf *vrf)
{
struct rtable *rth = rtnl_dereference(vrf->rth);
struct rtable *rth_local = rtnl_dereference(vrf->rth_local);
struct net *net = dev_net(dev);
struct dst_entry *dst;
RCU_INIT_POINTER(vrf->rth, NULL);
RCU_INIT_POINTER(vrf->rth_local, NULL);
synchronize_rcu();
if (rth)
dst_release(&rth->dst);
/* move dev in dst's to loopback so this VRF device can be deleted
* - based on dst_ifdown
*/
if (rth) {
dst = &rth->dst;
dev_put(dst->dev);
dst->dev = net->loopback_dev;
dev_hold(dst->dev);
dst_release(dst);
}
if (rth_local)
dst_release(&rth_local->dst);
if (rth_local) {
dst = &rth_local->dst;
dev_put(dst->dev);
dst->dev = net->loopback_dev;
dev_hold(dst->dev);
dst_release(dst);
}
}
static int vrf_rtable_create(struct net_device *dev)
@ -633,8 +662,8 @@ static void vrf_dev_uninit(struct net_device *dev)
struct net_device *port_dev;
struct list_head *iter;
vrf_rtable_release(vrf);
vrf_rt6_release(vrf);
vrf_rtable_release(dev, vrf);
vrf_rt6_release(dev, vrf);
netdev_for_each_lower_dev(dev, port_dev, iter)
vrf_del_slave(dev, port_dev);
@ -669,7 +698,7 @@ static int vrf_dev_init(struct net_device *dev)
return 0;
out_rth:
vrf_rtable_release(vrf);
vrf_rtable_release(dev, vrf);
out_stats:
free_percpu(dev->dstats);
dev->dstats = NULL;