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authorVeaceslav Falico <vfalico@redhat.com>2013-08-28 23:25:05 +0200
committerDavid S. Miller <davem@davemloft.net>2013-08-29 16:19:42 -0400
commit5d261913ca3daf6c2d21d38924235667b3d07c40 (patch)
treef15af2dea3316393cea047c637f434aa04db7726 /net/core/dev.c
parentaa9d85605f5ab070b64842b3eba797cf81698ae1 (diff)
downloadlinux-linaro-stable-5d261913ca3daf6c2d21d38924235667b3d07c40.tar.gz
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>
Diffstat (limited to 'net/core/dev.c')
-rw-r--r--net/core/dev.c285
1 files changed, 258 insertions, 27 deletions
diff --git a/net/core/dev.c b/net/core/dev.c
index 5072e2c1a072..2aa914eee057 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4369,7 +4369,16 @@ softnet_break:
struct netdev_adjacent {
struct net_device *dev;
+
+ /* upper master flag, there can only be one master device per list */
bool master;
+
+ /* indicates that this dev is our first-level lower/upper device */
+ bool neighbour;
+
+ /* counter for the number of times this device was added to us */
+ u16 ref_nr;
+
struct list_head list;
struct rcu_head rcu;
struct list_head search_list;
@@ -4408,18 +4417,34 @@ static bool __netdev_search_upper_dev(struct net_device *dev,
return ret;
}
-static struct netdev_adjacent *__netdev_find_upper(struct net_device *dev,
- struct net_device *upper_dev)
+static struct netdev_adjacent *__netdev_find_adj(struct net_device *dev,
+ struct net_device *adj_dev,
+ bool upper)
{
- struct netdev_adjacent *upper;
+ struct netdev_adjacent *adj;
+ struct list_head *dev_list;
- list_for_each_entry(upper, &dev->upper_dev_list, list) {
- if (upper->dev == upper_dev)
- return upper;
+ dev_list = upper ? &dev->upper_dev_list : &dev->lower_dev_list;
+
+ list_for_each_entry(adj, dev_list, list) {
+ if (adj->dev == adj_dev)
+ return adj;
}
return NULL;
}
+static inline struct netdev_adjacent *__netdev_find_upper(struct net_device *dev,
+ struct net_device *udev)
+{
+ return __netdev_find_adj(dev, udev, true);
+}
+
+static inline struct netdev_adjacent *__netdev_find_lower(struct net_device *dev,
+ struct net_device *ldev)
+{
+ return __netdev_find_adj(dev, ldev, false);
+}
+
/**
* netdev_has_upper_dev - Check if device is linked to an upper device
* @dev: device
@@ -4496,10 +4521,149 @@ struct net_device *netdev_master_upper_dev_get_rcu(struct net_device *dev)
}
EXPORT_SYMBOL(netdev_master_upper_dev_get_rcu);
+static int __netdev_adjacent_dev_insert(struct net_device *dev,
+ struct net_device *adj_dev,
+ bool neighbour, bool master,
+ bool upper)
+{
+ struct netdev_adjacent *adj;
+
+ adj = __netdev_find_adj(dev, adj_dev, upper);
+
+ if (adj) {
+ BUG_ON(neighbour);
+ adj->ref_nr++;
+ return 0;
+ }
+
+ adj = kmalloc(sizeof(*adj), GFP_KERNEL);
+ if (!adj)
+ return -ENOMEM;
+
+ adj->dev = adj_dev;
+ adj->master = master;
+ adj->neighbour = neighbour;
+ adj->ref_nr = 1;
+ INIT_LIST_HEAD(&adj->search_list);
+
+ dev_hold(adj_dev);
+ pr_debug("dev_hold for %s, because of %s link added from %s to %s\n",
+ adj_dev->name, upper ? "upper" : "lower", dev->name,
+ adj_dev->name);
+
+ if (!upper) {
+ list_add_tail_rcu(&adj->list, &dev->lower_dev_list);
+ return 0;
+ }
+
+ /* Ensure that master upper link is always the first item in list. */
+ if (master)
+ list_add_rcu(&adj->list, &dev->upper_dev_list);
+ else
+ list_add_tail_rcu(&adj->list, &dev->upper_dev_list);
+
+ return 0;
+}
+
+static inline int __netdev_upper_dev_insert(struct net_device *dev,
+ struct net_device *udev,
+ bool master, bool neighbour)
+{
+ return __netdev_adjacent_dev_insert(dev, udev, neighbour, master,
+ true);
+}
+
+static inline int __netdev_lower_dev_insert(struct net_device *dev,
+ struct net_device *ldev,
+ bool neighbour)
+{
+ return __netdev_adjacent_dev_insert(dev, ldev, neighbour, false,
+ false);
+}
+
+void __netdev_adjacent_dev_remove(struct net_device *dev,
+ struct net_device *adj_dev, bool upper)
+{
+ struct netdev_adjacent *adj;
+
+ if (upper)
+ adj = __netdev_find_upper(dev, adj_dev);
+ else
+ adj = __netdev_find_lower(dev, adj_dev);
+
+ if (!adj)
+ BUG();
+
+ if (adj->ref_nr > 1) {
+ adj->ref_nr--;
+ return;
+ }
+
+ list_del_rcu(&adj->list);
+ pr_debug("dev_put for %s, because of %s link removed from %s to %s\n",
+ adj_dev->name, upper ? "upper" : "lower", dev->name,
+ adj_dev->name);
+ dev_put(adj_dev);
+ kfree_rcu(adj, rcu);
+}
+
+static inline void __netdev_upper_dev_remove(struct net_device *dev,
+ struct net_device *udev)
+{
+ return __netdev_adjacent_dev_remove(dev, udev, true);
+}
+
+static inline void __netdev_lower_dev_remove(struct net_device *dev,
+ struct net_device *ldev)
+{
+ return __netdev_adjacent_dev_remove(dev, ldev, false);
+}
+
+int __netdev_adjacent_dev_insert_link(struct net_device *dev,
+ struct net_device *upper_dev,
+ bool master, bool neighbour)
+{
+ int ret;
+
+ ret = __netdev_upper_dev_insert(dev, upper_dev, master, neighbour);
+ if (ret)
+ return ret;
+
+ ret = __netdev_lower_dev_insert(upper_dev, dev, neighbour);
+ if (ret) {
+ __netdev_upper_dev_remove(dev, upper_dev);
+ return ret;
+ }
+
+ return 0;
+}
+
+static inline int __netdev_adjacent_dev_link(struct net_device *dev,
+ struct net_device *udev)
+{
+ return __netdev_adjacent_dev_insert_link(dev, udev, false, false);
+}
+
+static inline int __netdev_adjacent_dev_link_neighbour(struct net_device *dev,
+ struct net_device *udev,
+ bool master)
+{
+ return __netdev_adjacent_dev_insert_link(dev, udev, master, true);
+}
+
+void __netdev_adjacent_dev_unlink(struct net_device *dev,
+ struct net_device *upper_dev)
+{
+ __netdev_upper_dev_remove(dev, upper_dev);
+ __netdev_lower_dev_remove(upper_dev, dev);
+}
+
+
static int __netdev_upper_dev_link(struct net_device *dev,
struct net_device *upper_dev, bool master)
{
- struct netdev_adjacent *upper;
+ struct netdev_adjacent *i, *j, *to_i, *to_j;
+ int ret = 0;
ASSERT_RTNL();
@@ -4516,22 +4680,76 @@ static int __netdev_upper_dev_link(struct net_device *dev,
if (master && netdev_master_upper_dev_get(dev))
return -EBUSY;
- upper = kmalloc(sizeof(*upper), GFP_KERNEL);
- if (!upper)
- return -ENOMEM;
+ ret = __netdev_adjacent_dev_link_neighbour(dev, upper_dev, master);
+ if (ret)
+ return ret;
- upper->dev = upper_dev;
- upper->master = master;
- INIT_LIST_HEAD(&upper->search_list);
+ /* Now that we linked these devs, make all the upper_dev's
+ * upper_dev_list visible to every dev's lower_dev_list and vice
+ * versa, and don't forget the devices itself. All of these
+ * links are non-neighbours.
+ */
+ list_for_each_entry(i, &upper_dev->upper_dev_list, list) {
+ list_for_each_entry(j, &dev->lower_dev_list, list) {
+ ret = __netdev_adjacent_dev_link(i->dev, j->dev);
+ if (ret)
+ goto rollback_mesh;
+ }
+ }
+
+ /* add dev to every upper_dev's upper device */
+ list_for_each_entry(i, &upper_dev->upper_dev_list, list) {
+ ret = __netdev_adjacent_dev_link(dev, i->dev);
+ if (ret)
+ goto rollback_upper_mesh;
+ }
+
+ /* add upper_dev to every dev's lower device */
+ list_for_each_entry(i, &dev->lower_dev_list, list) {
+ ret = __netdev_adjacent_dev_link(i->dev, upper_dev);
+ if (ret)
+ goto rollback_lower_mesh;
+ }
- /* Ensure that master upper link is always the first item in list. */
- if (master)
- list_add_rcu(&upper->list, &dev->upper_dev_list);
- else
- list_add_tail_rcu(&upper->list, &dev->upper_dev_list);
- dev_hold(upper_dev);
call_netdevice_notifiers(NETDEV_CHANGEUPPER, dev);
return 0;
+
+rollback_lower_mesh:
+ to_i = i;
+ list_for_each_entry(i, &dev->lower_dev_list, list) {
+ if (i == to_i)
+ break;
+ __netdev_adjacent_dev_unlink(i->dev, upper_dev);
+ }
+
+ i = NULL;
+
+rollback_upper_mesh:
+ to_i = i;
+ list_for_each_entry(i, &upper_dev->upper_dev_list, list) {
+ if (i == to_i)
+ break;
+ __netdev_adjacent_dev_unlink(dev, i->dev);
+ }
+
+ i = j = NULL;
+
+rollback_mesh:
+ to_i = i;
+ to_j = j;
+ list_for_each_entry(i, &dev->lower_dev_list, list) {
+ list_for_each_entry(j, &upper_dev->upper_dev_list, list) {
+ if (i == to_i && j == to_j)
+ break;
+ __netdev_adjacent_dev_unlink(i->dev, j->dev);
+ }
+ if (i == to_i)
+ break;
+ }
+
+ __netdev_adjacent_dev_unlink(dev, upper_dev);
+
+ return ret;
}
/**
@@ -4580,16 +4798,28 @@ EXPORT_SYMBOL(netdev_master_upper_dev_link);
void netdev_upper_dev_unlink(struct net_device *dev,
struct net_device *upper_dev)
{
- struct netdev_adjacent *upper;
-
+ struct netdev_adjacent *i, *j;
ASSERT_RTNL();
- upper = __netdev_find_upper(dev, upper_dev);
- if (!upper)
- return;
- list_del_rcu(&upper->list);
- dev_put(upper_dev);
- kfree_rcu(upper, rcu);
+ __netdev_adjacent_dev_unlink(dev, upper_dev);
+
+ /* Here is the tricky part. We must remove all dev's lower
+ * devices from all upper_dev's upper devices and vice
+ * versa, to maintain the graph relationship.
+ */
+ list_for_each_entry(i, &dev->lower_dev_list, list)
+ list_for_each_entry(j, &upper_dev->upper_dev_list, list)
+ __netdev_adjacent_dev_unlink(i->dev, j->dev);
+
+ /* remove also the devices itself from lower/upper device
+ * list
+ */
+ list_for_each_entry(i, &dev->lower_dev_list, list)
+ __netdev_adjacent_dev_unlink(i->dev, upper_dev);
+
+ list_for_each_entry(i, &upper_dev->upper_dev_list, list)
+ __netdev_adjacent_dev_unlink(dev, i->dev);
+
call_netdevice_notifiers(NETDEV_CHANGEUPPER, dev);
}
EXPORT_SYMBOL(netdev_upper_dev_unlink);
@@ -5850,6 +6080,7 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
INIT_LIST_HEAD(&dev->unreg_list);
INIT_LIST_HEAD(&dev->link_watch_list);
INIT_LIST_HEAD(&dev->upper_dev_list);
+ INIT_LIST_HEAD(&dev->lower_dev_list);
dev->priv_flags = IFF_XMIT_DST_RELEASE;
setup(dev);