Merge branch 'per-netns-notifier'

Jiri Pirko says:

====================
net: introduce per-netns netdevice notifiers and use them in mlxsw

Some drivers, like mlxsw, are not interested in notifications coming in
for netdevices from other network namespaces. So introduce per-netns
notifiers and allow to reduce overhead by listening only for
notifications from the same netns.

This is also a preparation for upcoming patchset "devlink: allow devlink
instances to change network namespace". This resolves deadlock during
reload mlxsw into initial netns made possible by
328fbe747a ("net: Close race between {un, }register_netdevice_notifier() and setup_net()/cleanup_net()").
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2019-10-02 11:48:44 -04:00
commit df428e4049
4 changed files with 165 additions and 32 deletions

View File

@ -4864,7 +4864,8 @@ static int mlxsw_sp_init(struct mlxsw_core *mlxsw_core,
* respin.
*/
mlxsw_sp->netdevice_nb.notifier_call = mlxsw_sp_netdevice_event;
err = register_netdevice_notifier(&mlxsw_sp->netdevice_nb);
err = register_netdevice_notifier_net(&init_net,
&mlxsw_sp->netdevice_nb);
if (err) {
dev_err(mlxsw_sp->bus_info->dev, "Failed to register netdev notifier\n");
goto err_netdev_notifier;
@ -4887,7 +4888,8 @@ static int mlxsw_sp_init(struct mlxsw_core *mlxsw_core,
err_ports_create:
mlxsw_sp_dpipe_fini(mlxsw_sp);
err_dpipe_init:
unregister_netdevice_notifier(&mlxsw_sp->netdevice_nb);
unregister_netdevice_notifier_net(&init_net,
&mlxsw_sp->netdevice_nb);
err_netdev_notifier:
if (mlxsw_sp->clock)
mlxsw_sp->ptp_ops->fini(mlxsw_sp->ptp_state);
@ -4973,7 +4975,8 @@ static void mlxsw_sp_fini(struct mlxsw_core *mlxsw_core)
mlxsw_sp_ports_remove(mlxsw_sp);
mlxsw_sp_dpipe_fini(mlxsw_sp);
unregister_netdevice_notifier(&mlxsw_sp->netdevice_nb);
unregister_netdevice_notifier_net(&init_net,
&mlxsw_sp->netdevice_nb);
if (mlxsw_sp->clock) {
mlxsw_sp->ptp_ops->fini(mlxsw_sp->ptp_state);
mlxsw_sp->ptp_ops->clock_fini(mlxsw_sp->clock);

View File

@ -2504,6 +2504,9 @@ 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;
@ -2574,6 +2577,9 @@ extern rwlock_t dev_base_lock; /* Device list lock */
list_for_each_entry_safe(d, n, &(net)->dev_base_head, dev_list)
#define for_each_netdev_continue(net, d) \
list_for_each_entry_continue(d, &(net)->dev_base_head, dev_list)
#define for_each_netdev_continue_reverse(net, d) \
list_for_each_entry_continue_reverse(d, &(net)->dev_base_head, \
dev_list)
#define for_each_netdev_continue_rcu(net, d) \
list_for_each_entry_continue_rcu(d, &(net)->dev_base_head, dev_list)
#define for_each_netdev_in_bond_rcu(bond, slave) \

View File

@ -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;
@ -317,7 +320,8 @@ static inline struct net *read_pnet(const possible_net_t *pnet)
/* Protected by net_rwsem */
#define for_each_net(VAR) \
list_for_each_entry(VAR, &net_namespace_list, list)
#define for_each_net_continue_reverse(VAR) \
list_for_each_entry_continue_reverse(VAR, &net_namespace_list, list)
#define for_each_net_rcu(VAR) \
list_for_each_entry_rcu(VAR, &net_namespace_list, list)

View File

@ -1725,6 +1725,62 @@ static int call_netdevice_notifier(struct notifier_block *nb, unsigned long val,
return nb->notifier_call(nb, val, &info);
}
static int call_netdevice_register_notifiers(struct notifier_block *nb,
struct net_device *dev)
{
int err;
err = call_netdevice_notifier(nb, NETDEV_REGISTER, dev);
err = notifier_to_errno(err);
if (err)
return err;
if (!(dev->flags & IFF_UP))
return 0;
call_netdevice_notifier(nb, NETDEV_UP, dev);
return 0;
}
static void call_netdevice_unregister_notifiers(struct notifier_block *nb,
struct net_device *dev)
{
if (dev->flags & IFF_UP) {
call_netdevice_notifier(nb, NETDEV_GOING_DOWN,
dev);
call_netdevice_notifier(nb, NETDEV_DOWN, dev);
}
call_netdevice_notifier(nb, NETDEV_UNREGISTER, dev);
}
static int call_netdevice_register_net_notifiers(struct notifier_block *nb,
struct net *net)
{
struct net_device *dev;
int err;
for_each_netdev(net, dev) {
err = call_netdevice_register_notifiers(nb, dev);
if (err)
goto rollback;
}
return 0;
rollback:
for_each_netdev_continue_reverse(net, dev)
call_netdevice_unregister_notifiers(nb, dev);
return err;
}
static void call_netdevice_unregister_net_notifiers(struct notifier_block *nb,
struct net *net)
{
struct net_device *dev;
for_each_netdev(net, dev)
call_netdevice_unregister_notifiers(nb, dev);
}
static int dev_boot_phase = 1;
/**
@ -1743,8 +1799,6 @@ static int dev_boot_phase = 1;
int register_netdevice_notifier(struct notifier_block *nb)
{
struct net_device *dev;
struct net_device *last;
struct net *net;
int err;
@ -1757,17 +1811,9 @@ int register_netdevice_notifier(struct notifier_block *nb)
if (dev_boot_phase)
goto unlock;
for_each_net(net) {
for_each_netdev(net, dev) {
err = call_netdevice_notifier(nb, NETDEV_REGISTER, dev);
err = notifier_to_errno(err);
err = call_netdevice_register_net_notifiers(nb, net);
if (err)
goto rollback;
if (!(dev->flags & IFF_UP))
continue;
call_netdevice_notifier(nb, NETDEV_UP, dev);
}
}
unlock:
@ -1776,22 +1822,9 @@ unlock:
return err;
rollback:
last = dev;
for_each_net(net) {
for_each_netdev(net, dev) {
if (dev == last)
goto outroll;
for_each_net_continue_reverse(net)
call_netdevice_unregister_net_notifiers(nb, net);
if (dev->flags & IFF_UP) {
call_netdevice_notifier(nb, NETDEV_GOING_DOWN,
dev);
call_netdevice_notifier(nb, NETDEV_DOWN, dev);
}
call_netdevice_notifier(nb, NETDEV_UNREGISTER, dev);
}
}
outroll:
raw_notifier_chain_unregister(&netdev_chain, nb);
goto unlock;
}
@ -1841,6 +1874,80 @@ unlock:
}
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
@ -1853,7 +1960,18 @@ 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);
}
@ -9752,6 +9870,8 @@ 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: