path: root/net
diff options
authorEric W. Biederman <ebiederm@maxwell.aristanetworks.com>2008-11-07 22:54:20 -0800
committerDavid S. Miller <davem@davemloft.net>2008-11-07 22:54:20 -0800
commit505d4f73dda9e20d59da05008f1f5eb432613e71 (patch)
treea30032d6474ce1d8dea1853c1907f4c3bdd8a19c /net
parent5d6d480908300a0c0b3be8b58567dfcef62c83a5 (diff)
net: Guaranetee the proper ordering of the loopback device. v2
I was recently hunting a bug that occurred in network namespace cleanup. In looking at the code it became apparrent that we have and will continue to have cases where if we have anything going on in a network namespace there will be assumptions that the loopback device is present. Things like sending igmp unsubscribe messages when we bring down network devices invokes the routing code which assumes that at least the loopback driver is present. Therefore to avoid magic initcall ordering hackery that is hard to follow and hard to get right insert a call to register the loopback device directly from net_dev_init(). This guarantes that the loopback device is the first device registered and the last network device to go away. But do it carefully so we register the loopback device after we clear dev_boot_phase. Signed-off-by: Eric W. Biederman <ebiederm@maxwell.aristanetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
1 files changed, 17 insertions, 5 deletions
diff --git a/net/core/dev.c b/net/core/dev.c
index 2306d56fbb5..31568b2068a 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4909,9 +4909,6 @@ static int __init net_dev_init(void)
if (register_pernet_subsys(&netdev_net_ops))
goto out;
- if (register_pernet_device(&default_device_ops))
- goto out;
* Initialise the packet receive queues.
@@ -4928,10 +4925,25 @@ static int __init net_dev_init(void)
queue->backlog.weight = weight_p;
- netdev_dma_register();
dev_boot_phase = 0;
+ /* The loopback device is special if any other network devices
+ * is present in a network namespace the loopback device must
+ * be present. Since we now dynamically allocate and free the
+ * loopback device ensure this invariant is maintained by
+ * keeping the loopback device as the first device on the
+ * list of network devices. Ensuring the loopback devices
+ * is the first device that appears and the last network device
+ * that disappears.
+ */
+ if (register_pernet_device(&loopback_net_ops))
+ goto out;
+ if (register_pernet_device(&default_device_ops))
+ goto out;
+ netdev_dma_register();
open_softirq(NET_TX_SOFTIRQ, net_tx_action);
open_softirq(NET_RX_SOFTIRQ, net_rx_action);