From: Jiri Pirko <j...@mellanox.com>
Often the code for example in drivers is interested in getting notifier
call only from certain network namespace. In addition to the existing
global netdevice notifier chain introduce per-netns chains and allow
users to register to that. Eventually this would eliminate unnecessary
overhead in case there are many netdevices in many network namespaces.
Signed-off-by: Jiri Pirko <j...@mellanox.com>
---
include/linux/netdevice.h | 3 ++
include/net/net_namespace.h | 3 ++
net/core/dev.c | 87 +++++++++++++++++++++++++++++++++++++
3 files changed, 93 insertions(+)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 4f390eec106b..184f54f1b9e1 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2494,6 +2494,9 @@ const char *netdev_cmd_to_name(enum netdev_cmd cmd);
int register_netdevice_notifier(struct notifier_block *nb);
int unregister_netdevice_notifier(struct notifier_block *nb);
+int register_netdevice_notifier_net(struct net *net, struct notifier_block
*nb);
+int unregister_netdevice_notifier_net(struct net *net,
+ struct notifier_block *nb);
struct netdev_notifier_info {
struct net_device *dev;
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index c5a98e03591d..5ac2bb16d4b3 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -36,6 +36,7 @@
#include <linux/ns_common.h>
#include <linux/idr.h>
#include <linux/skbuff.h>
+#include <linux/notifier.h>
struct user_namespace;
struct proc_dir_entry;
@@ -96,6 +97,8 @@ struct net {
struct list_head dev_base_head;
struct hlist_head *dev_name_head;
struct hlist_head *dev_index_head;
+ struct raw_notifier_head netdev_chain;
+
unsigned int dev_base_seq; /* protected by rtnl_mutex */
int ifindex;
unsigned int dev_unreg_count;
diff --git a/net/core/dev.c b/net/core/dev.c
index 6a87d0e71201..3302cefd3041 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1766,6 +1766,80 @@ int unregister_netdevice_notifier(struct notifier_block
*nb)
}
EXPORT_SYMBOL(unregister_netdevice_notifier);
+/**
+ * register_netdevice_notifier_net - register a per-netns network notifier
block
+ * @net: network namespace
+ * @nb: notifier
+ *
+ * Register a notifier to be called when network device events occur.
+ * The notifier passed is linked into the kernel structures and must
+ * not be reused until it has been unregistered. A negative errno code
+ * is returned on a failure.
+ *
+ * When registered all registration and up events are replayed
+ * to the new notifier to allow device to have a race free
+ * view of the network device list.
+ */
+
+int register_netdevice_notifier_net(struct net *net, struct notifier_block *nb)
+{
+ int err;
+
+ rtnl_lock();
+ err = raw_notifier_chain_register(&net->netdev_chain, nb);
+ if (err)
+ goto unlock;
+ if (dev_boot_phase)
+ goto unlock;
+
+ err = call_netdevice_register_net_notifiers(nb, net);
+ if (err)
+ goto chain_unregister;
+
+unlock:
+ rtnl_unlock();
+ return err;
+
+chain_unregister:
+ raw_notifier_chain_unregister(&netdev_chain, nb);
+ goto unlock;
+}
+EXPORT_SYMBOL(register_netdevice_notifier_net);
+
+/**
+ * unregister_netdevice_notifier_net - unregister a per-netns
+ * network notifier block
+ * @net: network namespace
+ * @nb: notifier
+ *
+ * Unregister a notifier previously registered by
+ * register_netdevice_notifier(). The notifier is unlinked into the
+ * kernel structures and may then be reused. A negative errno code
+ * is returned on a failure.
+ *
+ * After unregistering unregister and down device events are synthesized
+ * for all devices on the device list to the removed notifier to remove
+ * the need for special case cleanup code.
+ */
+
+int unregister_netdevice_notifier_net(struct net *net,
+ struct notifier_block *nb)
+{
+ int err;
+
+ rtnl_lock();
+ err = raw_notifier_chain_unregister(&net->netdev_chain, nb);
+ if (err)
+ goto unlock;
+
+ call_netdevice_unregister_net_notifiers(nb, net);
+
+unlock:
+ rtnl_unlock();
+ return err;
+}
+EXPORT_SYMBOL(unregister_netdevice_notifier_net);
+
/**
* call_netdevice_notifiers_info - call all network notifier blocks
* @val: value passed unmodified to notifier function
@@ -1778,7 +1852,18 @@ EXPORT_SYMBOL(unregister_netdevice_notifier);
static int call_netdevice_notifiers_info(unsigned long val,
struct netdev_notifier_info *info)
{
+ struct net *net = dev_net(info->dev);
+ int ret;
+
ASSERT_RTNL();
+
+ /* Run per-netns notifier block chain first, then run the global one.
+ * Hopefully, one day, the global one is going to be removed after
+ * all notifier block registrators get converted to be per-netns.
+ */
+ ret = raw_notifier_call_chain(&net->netdev_chain, val, info);
+ if (ret & NOTIFY_STOP_MASK)
+ return ret;
return raw_notifier_call_chain(&netdev_chain, val, info);
}
@@ -9668,6 +9753,8 @@ static int __net_init netdev_init(struct net *net)
if (net->dev_index_head == NULL)
goto err_idx;
+ RAW_INIT_NOTIFIER_HEAD(&net->netdev_chain);
+
return 0;
err_idx:
--
2.21.0
