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net: add lower_dev_list to net_device and make a full mesh
This patch adds lower_dev_list list_head to net_device, which is the same as upper_dev_list, only for lower devices, and begins to use it in the same way as the upper list. It also changes the way the whole adjacent device lists work - now they contain *all* of upper/lower devices, not only the first level. The first level devices are distinguished by the bool neighbour field in netdev_adjacent, also added by this patch. There are cases when a device can be added several times to the adjacent list, the simplest would be: /---- eth0.10 ---\ eth0- --- bond0 \---- eth0.20 ---/ where both bond0 and eth0 'see' each other in the adjacent lists two times. To avoid duplication of netdev_adjacent structures ref_nr is being kept as the number of times the device was added to the list. The 'full view' is achieved by adding, on link creation, all of the upper_dev's upper_dev_list devices as upper devices to all of the lower_dev's lower_dev_list devices (and to the lower_dev itself), and vice versa. On unlink they are removed using the same logic. I've tested it with thousands vlans/bonds/bridges, everything works ok and no observable lags even on a huge number of interfaces. Memory footprint for 128 devices interconnected with each other via both upper and lower (which is impossible, but for the comparison) lists would be: 128*128*2*sizeof(netdev_adjacent) = 1.5MB but in the real world we usualy have at most several devices with slaves and a lot of vlans, so the footprint will be much lower. CC: "David S. Miller" <davem@davemloft.net> CC: Eric Dumazet <edumazet@google.com> CC: Jiri Pirko <jiri@resnulli.us> CC: Alexander Duyck <alexander.h.duyck@intel.com> CC: Cong Wang <amwang@redhat.com> Signed-off-by: Veaceslav Falico <vfalico@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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parent
aa9d85605f
commit
5d261913ca
2 changed files with 259 additions and 27 deletions
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@ -1125,6 +1125,7 @@ struct net_device {
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struct list_head napi_list;
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struct list_head unreg_list;
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struct list_head upper_dev_list; /* List of upper devices */
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struct list_head lower_dev_list;
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/* currently active device features */
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285
net/core/dev.c
285
net/core/dev.c
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@ -4369,7 +4369,16 @@ static void net_rx_action(struct softirq_action *h)
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struct netdev_adjacent {
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struct net_device *dev;
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/* upper master flag, there can only be one master device per list */
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bool master;
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/* indicates that this dev is our first-level lower/upper device */
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bool neighbour;
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/* counter for the number of times this device was added to us */
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u16 ref_nr;
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struct list_head list;
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struct rcu_head rcu;
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struct list_head search_list;
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@ -4408,18 +4417,34 @@ static bool __netdev_search_upper_dev(struct net_device *dev,
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return ret;
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}
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static struct netdev_adjacent *__netdev_find_upper(struct net_device *dev,
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struct net_device *upper_dev)
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static struct netdev_adjacent *__netdev_find_adj(struct net_device *dev,
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struct net_device *adj_dev,
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bool upper)
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{
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struct netdev_adjacent *upper;
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struct netdev_adjacent *adj;
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struct list_head *dev_list;
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list_for_each_entry(upper, &dev->upper_dev_list, list) {
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if (upper->dev == upper_dev)
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return upper;
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dev_list = upper ? &dev->upper_dev_list : &dev->lower_dev_list;
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list_for_each_entry(adj, dev_list, list) {
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if (adj->dev == adj_dev)
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return adj;
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}
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return NULL;
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}
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static inline struct netdev_adjacent *__netdev_find_upper(struct net_device *dev,
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struct net_device *udev)
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{
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return __netdev_find_adj(dev, udev, true);
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}
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static inline struct netdev_adjacent *__netdev_find_lower(struct net_device *dev,
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struct net_device *ldev)
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{
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return __netdev_find_adj(dev, ldev, false);
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}
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/**
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* netdev_has_upper_dev - Check if device is linked to an upper device
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* @dev: device
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@ -4496,10 +4521,149 @@ struct net_device *netdev_master_upper_dev_get_rcu(struct net_device *dev)
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}
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EXPORT_SYMBOL(netdev_master_upper_dev_get_rcu);
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static int __netdev_adjacent_dev_insert(struct net_device *dev,
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struct net_device *adj_dev,
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bool neighbour, bool master,
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bool upper)
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{
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struct netdev_adjacent *adj;
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adj = __netdev_find_adj(dev, adj_dev, upper);
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if (adj) {
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BUG_ON(neighbour);
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adj->ref_nr++;
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return 0;
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}
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adj = kmalloc(sizeof(*adj), GFP_KERNEL);
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if (!adj)
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return -ENOMEM;
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adj->dev = adj_dev;
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adj->master = master;
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adj->neighbour = neighbour;
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adj->ref_nr = 1;
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INIT_LIST_HEAD(&adj->search_list);
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dev_hold(adj_dev);
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pr_debug("dev_hold for %s, because of %s link added from %s to %s\n",
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adj_dev->name, upper ? "upper" : "lower", dev->name,
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adj_dev->name);
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if (!upper) {
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list_add_tail_rcu(&adj->list, &dev->lower_dev_list);
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return 0;
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}
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/* Ensure that master upper link is always the first item in list. */
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if (master)
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list_add_rcu(&adj->list, &dev->upper_dev_list);
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else
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list_add_tail_rcu(&adj->list, &dev->upper_dev_list);
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return 0;
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}
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static inline int __netdev_upper_dev_insert(struct net_device *dev,
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struct net_device *udev,
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bool master, bool neighbour)
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{
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return __netdev_adjacent_dev_insert(dev, udev, neighbour, master,
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true);
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}
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static inline int __netdev_lower_dev_insert(struct net_device *dev,
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struct net_device *ldev,
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bool neighbour)
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{
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return __netdev_adjacent_dev_insert(dev, ldev, neighbour, false,
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false);
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}
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void __netdev_adjacent_dev_remove(struct net_device *dev,
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struct net_device *adj_dev, bool upper)
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{
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struct netdev_adjacent *adj;
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if (upper)
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adj = __netdev_find_upper(dev, adj_dev);
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else
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adj = __netdev_find_lower(dev, adj_dev);
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if (!adj)
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BUG();
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if (adj->ref_nr > 1) {
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adj->ref_nr--;
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return;
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}
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list_del_rcu(&adj->list);
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pr_debug("dev_put for %s, because of %s link removed from %s to %s\n",
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adj_dev->name, upper ? "upper" : "lower", dev->name,
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adj_dev->name);
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dev_put(adj_dev);
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kfree_rcu(adj, rcu);
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}
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static inline void __netdev_upper_dev_remove(struct net_device *dev,
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struct net_device *udev)
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{
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return __netdev_adjacent_dev_remove(dev, udev, true);
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}
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static inline void __netdev_lower_dev_remove(struct net_device *dev,
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struct net_device *ldev)
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{
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return __netdev_adjacent_dev_remove(dev, ldev, false);
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}
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int __netdev_adjacent_dev_insert_link(struct net_device *dev,
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struct net_device *upper_dev,
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bool master, bool neighbour)
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{
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int ret;
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ret = __netdev_upper_dev_insert(dev, upper_dev, master, neighbour);
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if (ret)
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return ret;
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ret = __netdev_lower_dev_insert(upper_dev, dev, neighbour);
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if (ret) {
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__netdev_upper_dev_remove(dev, upper_dev);
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return ret;
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}
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return 0;
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}
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static inline int __netdev_adjacent_dev_link(struct net_device *dev,
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struct net_device *udev)
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{
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return __netdev_adjacent_dev_insert_link(dev, udev, false, false);
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}
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static inline int __netdev_adjacent_dev_link_neighbour(struct net_device *dev,
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struct net_device *udev,
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bool master)
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{
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return __netdev_adjacent_dev_insert_link(dev, udev, master, true);
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}
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void __netdev_adjacent_dev_unlink(struct net_device *dev,
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struct net_device *upper_dev)
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{
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__netdev_upper_dev_remove(dev, upper_dev);
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__netdev_lower_dev_remove(upper_dev, dev);
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}
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static int __netdev_upper_dev_link(struct net_device *dev,
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struct net_device *upper_dev, bool master)
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{
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struct netdev_adjacent *upper;
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struct netdev_adjacent *i, *j, *to_i, *to_j;
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int ret = 0;
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ASSERT_RTNL();
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@ -4516,22 +4680,76 @@ static int __netdev_upper_dev_link(struct net_device *dev,
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if (master && netdev_master_upper_dev_get(dev))
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return -EBUSY;
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upper = kmalloc(sizeof(*upper), GFP_KERNEL);
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if (!upper)
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return -ENOMEM;
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ret = __netdev_adjacent_dev_link_neighbour(dev, upper_dev, master);
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if (ret)
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return ret;
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upper->dev = upper_dev;
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upper->master = master;
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INIT_LIST_HEAD(&upper->search_list);
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/* Now that we linked these devs, make all the upper_dev's
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* upper_dev_list visible to every dev's lower_dev_list and vice
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* versa, and don't forget the devices itself. All of these
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* links are non-neighbours.
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*/
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list_for_each_entry(i, &upper_dev->upper_dev_list, list) {
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list_for_each_entry(j, &dev->lower_dev_list, list) {
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ret = __netdev_adjacent_dev_link(i->dev, j->dev);
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if (ret)
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goto rollback_mesh;
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}
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}
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/* add dev to every upper_dev's upper device */
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list_for_each_entry(i, &upper_dev->upper_dev_list, list) {
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ret = __netdev_adjacent_dev_link(dev, i->dev);
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if (ret)
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goto rollback_upper_mesh;
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}
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/* add upper_dev to every dev's lower device */
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list_for_each_entry(i, &dev->lower_dev_list, list) {
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ret = __netdev_adjacent_dev_link(i->dev, upper_dev);
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if (ret)
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goto rollback_lower_mesh;
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}
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/* Ensure that master upper link is always the first item in list. */
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if (master)
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list_add_rcu(&upper->list, &dev->upper_dev_list);
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else
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list_add_tail_rcu(&upper->list, &dev->upper_dev_list);
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dev_hold(upper_dev);
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call_netdevice_notifiers(NETDEV_CHANGEUPPER, dev);
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return 0;
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rollback_lower_mesh:
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to_i = i;
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list_for_each_entry(i, &dev->lower_dev_list, list) {
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if (i == to_i)
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break;
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__netdev_adjacent_dev_unlink(i->dev, upper_dev);
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}
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i = NULL;
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rollback_upper_mesh:
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to_i = i;
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list_for_each_entry(i, &upper_dev->upper_dev_list, list) {
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if (i == to_i)
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break;
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__netdev_adjacent_dev_unlink(dev, i->dev);
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}
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i = j = NULL;
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rollback_mesh:
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to_i = i;
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to_j = j;
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list_for_each_entry(i, &dev->lower_dev_list, list) {
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list_for_each_entry(j, &upper_dev->upper_dev_list, list) {
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if (i == to_i && j == to_j)
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break;
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__netdev_adjacent_dev_unlink(i->dev, j->dev);
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}
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if (i == to_i)
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break;
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}
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__netdev_adjacent_dev_unlink(dev, upper_dev);
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return ret;
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}
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/**
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@ -4580,16 +4798,28 @@ EXPORT_SYMBOL(netdev_master_upper_dev_link);
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void netdev_upper_dev_unlink(struct net_device *dev,
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struct net_device *upper_dev)
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{
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struct netdev_adjacent *upper;
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struct netdev_adjacent *i, *j;
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ASSERT_RTNL();
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upper = __netdev_find_upper(dev, upper_dev);
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if (!upper)
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return;
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list_del_rcu(&upper->list);
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dev_put(upper_dev);
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kfree_rcu(upper, rcu);
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__netdev_adjacent_dev_unlink(dev, upper_dev);
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/* Here is the tricky part. We must remove all dev's lower
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* devices from all upper_dev's upper devices and vice
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* versa, to maintain the graph relationship.
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*/
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list_for_each_entry(i, &dev->lower_dev_list, list)
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list_for_each_entry(j, &upper_dev->upper_dev_list, list)
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__netdev_adjacent_dev_unlink(i->dev, j->dev);
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/* remove also the devices itself from lower/upper device
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* list
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*/
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list_for_each_entry(i, &dev->lower_dev_list, list)
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__netdev_adjacent_dev_unlink(i->dev, upper_dev);
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list_for_each_entry(i, &upper_dev->upper_dev_list, list)
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__netdev_adjacent_dev_unlink(dev, i->dev);
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call_netdevice_notifiers(NETDEV_CHANGEUPPER, dev);
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}
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EXPORT_SYMBOL(netdev_upper_dev_unlink);
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@ -5850,6 +6080,7 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
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INIT_LIST_HEAD(&dev->unreg_list);
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INIT_LIST_HEAD(&dev->link_watch_list);
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INIT_LIST_HEAD(&dev->upper_dev_list);
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INIT_LIST_HEAD(&dev->lower_dev_list);
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dev->priv_flags = IFF_XMIT_DST_RELEASE;
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setup(dev);
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