[PATCH RESEND net-next 1/2] net: Remove net_rwsem from {, un}register_netdevice_notifier()
flat view
STALE3129d
From: Kirill Tkhai <hidden>
Date: 2018-03-30 16:38:41
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
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: f0b07bb151b0 "net: Introduce net_rwsem to protect net_namespace_list"
Signed-off-by: Kirill Tkhai <redacted>
---
net/core/dev.c | 5 -----
1 file changed, 5 deletions(-)
diff --git a/net/core/dev.c b/net/core/dev.c
index 07da7add4845..8edb58829124 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c@@ -1633,7 +1633,6 @@ int register_netdevice_notifier(struct notifier_block *nb) goto unlock; if (dev_boot_phase) goto unlock; - down_read(&net_rwsem); for_each_net(net) { for_each_netdev(net, dev) { err = call_netdevice_notifier(nb, NETDEV_REGISTER, dev);
@@ -1647,7 +1646,6 @@ int register_netdevice_notifier(struct notifier_block *nb) call_netdevice_notifier(nb, NETDEV_UP, dev); } } - up_read(&net_rwsem); unlock: rtnl_unlock();
@@ -1671,7 +1669,6 @@ int register_netdevice_notifier(struct notifier_block *nb) } outroll: - up_read(&net_rwsem); raw_notifier_chain_unregister(&netdev_chain, nb); goto unlock; }
@@ -1704,7 +1701,6 @@ int unregister_netdevice_notifier(struct notifier_block *nb) if (err) goto unlock; - down_read(&net_rwsem); for_each_net(net) { for_each_netdev(net, dev) { if (dev->flags & IFF_UP) {
@@ -1715,7 +1711,6 @@ int unregister_netdevice_notifier(struct notifier_block *nb) call_netdevice_notifier(nb, NETDEV_UNREGISTER, dev); } } - up_read(&net_rwsem); unlock: rtnl_unlock(); up_write(&pernet_ops_rwsem);