Commit fc1dd369 authored by Kirill Tkhai's avatar Kirill Tkhai Committed by David S. Miller

net: Remove net_rwsem from {, un}register_netdevice_notifier()

These functions take net_rwsem, while wireless_nlevent_flush()
also takes it. But down_read() can't be taken recursive,
because of rw_semaphore design, which prevents it to be occupied
by only readers forever.

Since we take pernet_ops_rwsem in {,un}register_netdevice_notifier(),
net list can't change, so these down_read()/up_read() can be removed.

Fixes: f0b07bb1 "net: Introduce net_rwsem to protect net_namespace_list"
Signed-off-by: default avatarKirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c679f6a2
...@@ -1633,7 +1633,6 @@ int register_netdevice_notifier(struct notifier_block *nb) ...@@ -1633,7 +1633,6 @@ int register_netdevice_notifier(struct notifier_block *nb)
goto unlock; goto unlock;
if (dev_boot_phase) if (dev_boot_phase)
goto unlock; goto unlock;
down_read(&net_rwsem);
for_each_net(net) { for_each_net(net) {
for_each_netdev(net, dev) { for_each_netdev(net, dev) {
err = call_netdevice_notifier(nb, NETDEV_REGISTER, dev); err = call_netdevice_notifier(nb, NETDEV_REGISTER, dev);
...@@ -1647,7 +1646,6 @@ int register_netdevice_notifier(struct notifier_block *nb) ...@@ -1647,7 +1646,6 @@ int register_netdevice_notifier(struct notifier_block *nb)
call_netdevice_notifier(nb, NETDEV_UP, dev); call_netdevice_notifier(nb, NETDEV_UP, dev);
} }
} }
up_read(&net_rwsem);
unlock: unlock:
rtnl_unlock(); rtnl_unlock();
...@@ -1671,7 +1669,6 @@ int register_netdevice_notifier(struct notifier_block *nb) ...@@ -1671,7 +1669,6 @@ int register_netdevice_notifier(struct notifier_block *nb)
} }
outroll: outroll:
up_read(&net_rwsem);
raw_notifier_chain_unregister(&netdev_chain, nb); raw_notifier_chain_unregister(&netdev_chain, nb);
goto unlock; goto unlock;
} }
...@@ -1704,7 +1701,6 @@ int unregister_netdevice_notifier(struct notifier_block *nb) ...@@ -1704,7 +1701,6 @@ int unregister_netdevice_notifier(struct notifier_block *nb)
if (err) if (err)
goto unlock; goto unlock;
down_read(&net_rwsem);
for_each_net(net) { for_each_net(net) {
for_each_netdev(net, dev) { for_each_netdev(net, dev) {
if (dev->flags & IFF_UP) { if (dev->flags & IFF_UP) {
...@@ -1715,7 +1711,6 @@ int unregister_netdevice_notifier(struct notifier_block *nb) ...@@ -1715,7 +1711,6 @@ int unregister_netdevice_notifier(struct notifier_block *nb)
call_netdevice_notifier(nb, NETDEV_UNREGISTER, dev); call_netdevice_notifier(nb, NETDEV_UNREGISTER, dev);
} }
} }
up_read(&net_rwsem);
unlock: unlock:
rtnl_unlock(); rtnl_unlock();
up_write(&pernet_ops_rwsem); up_write(&pernet_ops_rwsem);
......
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