2 files changed, 219 insertions, 21 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index c93df7cf187b..6c6490e15cd4 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -4324,6 +4324,16 @@ int netdev_master_upper_dev_link(struct net_device *dev,
                                  struct netlink_ext_ack *extack);
 void netdev_upper_dev_unlink(struct net_device *dev,
                              struct net_device *upper_dev);
+int netdev_adjacent_change_prepare(struct net_device *old_dev,
+                                   struct net_device *new_dev,
+                                   struct net_device *dev,
+                                   struct netlink_ext_ack *extack);
+void netdev_adjacent_change_commit(struct net_device *old_dev,
+                                   struct net_device *new_dev,
+                                   struct net_device *dev);
+void netdev_adjacent_change_abort(struct net_device *old_dev,
+                                  struct net_device *new_dev,
+                                  struct net_device *dev);
 void netdev_adjacent_rename_links(struct net_device *dev, char *oldname);
 void *netdev_lower_dev_get_private(struct net_device *dev,
                                    struct net_device *lower_dev);
diff --git a/net/core/dev.c b/net/core/dev.c
index 5722a81b6edd..092c094038b6 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6408,6 +6408,9 @@ struct netdev_adjacent {
         /* upper master flag, there can only be one master device per list */
         bool master;
 
+        /* lookup ignore flag */
+        bool ignore;
+
         /* counter for the number of times this device was added to us */
         u16 ref_nr;
 
@@ -6430,7 +6433,7 @@ static struct netdev_adjacent *__netdev_find_adj(struct net_device *adj_dev,
         return NULL;
 }
 
-static int __netdev_has_upper_dev(struct net_device *upper_dev, void *data)
+static int ____netdev_has_upper_dev(struct net_device *upper_dev, void *data)
 {
         struct net_device *dev = data;
 
@@ -6451,7 +6454,7 @@ bool netdev_has_upper_dev(struct net_device *dev,
 {
         ASSERT_RTNL();
 
-        return netdev_walk_all_upper_dev_rcu(dev, __netdev_has_upper_dev,
+        return netdev_walk_all_upper_dev_rcu(dev, ____netdev_has_upper_dev,
                                              upper_dev);
 }
 EXPORT_SYMBOL(netdev_has_upper_dev);
@@ -6469,7 +6472,7 @@ EXPORT_SYMBOL(netdev_has_upper_dev);
 bool netdev_has_upper_dev_all_rcu(struct net_device *dev,
                                   struct net_device *upper_dev)
 {
-        return !!netdev_walk_all_upper_dev_rcu(dev, __netdev_has_upper_dev,
+        return !!netdev_walk_all_upper_dev_rcu(dev, ____netdev_has_upper_dev,
                                                upper_dev);
 }
 EXPORT_SYMBOL(netdev_has_upper_dev_all_rcu);
@@ -6513,6 +6516,22 @@ struct net_device *netdev_master_upper_dev_get(struct net_device *dev)
 }
 EXPORT_SYMBOL(netdev_master_upper_dev_get);
 
+static struct net_device *__netdev_master_upper_dev_get(struct net_device *dev)
+{
+        struct netdev_adjacent *upper;
+
+        ASSERT_RTNL();
+
+        if (list_empty(&dev->adj_list.upper))
+                return NULL;
+
+        upper = list_first_entry(&dev->adj_list.upper,
+                                 struct netdev_adjacent, list);
+        if (likely(upper->master) && !upper->ignore)
+                return upper->dev;
+        return NULL;
+}
+
 /**
  * netdev_has_any_lower_dev - Check if device is linked to some device
  * @dev: device
@@ -6563,8 +6582,9 @@ struct net_device *netdev_upper_get_next_dev_rcu(struct net_device *dev,
 }
 EXPORT_SYMBOL(netdev_upper_get_next_dev_rcu);
 
-static struct net_device *netdev_next_upper_dev(struct net_device *dev,
-                                                struct list_head **iter)
+static struct net_device *__netdev_next_upper_dev(struct net_device *dev,
+                                                  struct list_head **iter,
+                                                  bool *ignore)
 {
         struct netdev_adjacent *upper;
 
@@ -6574,6 +6594,7 @@ static struct net_device *netdev_next_upper_dev(struct net_device *dev,
                 return NULL;
 
         *iter = &upper->list;
+        *ignore = upper->ignore;
 
         return upper->dev;
 }
@@ -6595,14 +6616,15 @@ static struct net_device *netdev_next_upper_dev_rcu(struct net_device *dev,
         return upper->dev;
 }
 
-static int netdev_walk_all_upper_dev(struct net_device *dev,
-                                     int (*fn)(struct net_device *dev,
-                                               void *data),
-                                     void *data)
+static int __netdev_walk_all_upper_dev(struct net_device *dev,
+                                       int (*fn)(struct net_device *dev,
+                                                 void *data),
+                                       void *data)
 {
         struct net_device *udev, *next, *now, *dev_stack[MAX_NEST_DEV + 1];
         struct list_head *niter, *iter, *iter_stack[MAX_NEST_DEV + 1];
         int ret, cur = 0;
+        bool ignore;
 
         now = dev;
         iter = &dev->adj_list.upper;
@@ -6616,9 +6638,11 @@ static int netdev_walk_all_upper_dev(struct net_device *dev,
 
                 next = NULL;
                 while (1) {
-                        udev = netdev_next_upper_dev(now, &iter);
+                        udev = __netdev_next_upper_dev(now, &iter, &ignore);
                         if (!udev)
                                 break;
+                        if (ignore)
+                                continue;
 
                         next = udev;
                         niter = &udev->adj_list.upper;
@@ -6688,6 +6712,15 @@ int netdev_walk_all_upper_dev_rcu(struct net_device *dev,
 }
 EXPORT_SYMBOL_GPL(netdev_walk_all_upper_dev_rcu);
 
+static bool __netdev_has_upper_dev(struct net_device *dev,
+                                   struct net_device *upper_dev)
+{
+        ASSERT_RTNL();
+
+        return __netdev_walk_all_upper_dev(dev, ____netdev_has_upper_dev,
+                                           upper_dev);
+}
+
 /**
  * netdev_lower_get_next_private - Get the next ->private from the
  *                                 lower neighbour list
@@ -6784,6 +6817,23 @@ static struct net_device *netdev_next_lower_dev(struct net_device *dev,
         return lower->dev;
 }
 
+static struct net_device *__netdev_next_lower_dev(struct net_device *dev,
+                                                  struct list_head **iter,
+                                                  bool *ignore)
+{
+        struct netdev_adjacent *lower;
+
+        lower = list_entry((*iter)->next, struct netdev_adjacent, list);
+
+        if (&lower->list == &dev->adj_list.lower)
+                return NULL;
+
+        *iter = &lower->list;
+        *ignore = lower->ignore;
+
+        return lower->dev;
+}
+
 int netdev_walk_all_lower_dev(struct net_device *dev,
                               int (*fn)(struct net_device *dev,
                                         void *data),
@@ -6831,6 +6881,55 @@ int netdev_walk_all_lower_dev(struct net_device *dev,
 }
 EXPORT_SYMBOL_GPL(netdev_walk_all_lower_dev);
 
+static int __netdev_walk_all_lower_dev(struct net_device *dev,
+                                       int (*fn)(struct net_device *dev,
+                                                 void *data),
+                                       void *data)
+{
+        struct net_device *ldev, *next, *now, *dev_stack[MAX_NEST_DEV + 1];
+        struct list_head *niter, *iter, *iter_stack[MAX_NEST_DEV + 1];
+        int ret, cur = 0;
+        bool ignore;
+
+        now = dev;
+        iter = &dev->adj_list.lower;
+
+        while (1) {
+                if (now != dev) {
+                        ret = fn(now, data);
+                        if (ret)
+                                return ret;
+                }
+
+                next = NULL;
+                while (1) {
+                        ldev = __netdev_next_lower_dev(now, &iter, &ignore);
+                        if (!ldev)
+                                break;
+                        if (ignore)
+                                continue;
+
+                        next = ldev;
+                        niter = &ldev->adj_list.lower;
+                        dev_stack[cur] = now;
+                        iter_stack[cur++] = iter;
+                        break;
+                }
+
+                if (!next) {
+                        if (!cur)
+                                return 0;
+                        next = dev_stack[--cur];
+                        niter = iter_stack[cur];
+                }
+
+                now = next;
+                iter = niter;
+        }
+
+        return 0;
+}
+
 static struct net_device *netdev_next_lower_dev_rcu(struct net_device *dev,
                                                     struct list_head **iter)
 {
@@ -6850,11 +6949,14 @@ static u8 __netdev_upper_depth(struct net_device *dev)
         struct net_device *udev;
         struct list_head *iter;
         u8 max_depth = 0;
+        bool ignore;
 
         for (iter = &dev->adj_list.upper,
-             udev = netdev_next_upper_dev(dev, &iter);
+             udev = __netdev_next_upper_dev(dev, &iter, &ignore);
              udev;
-             udev = netdev_next_upper_dev(dev, &iter)) {
+             udev = __netdev_next_upper_dev(dev, &iter, &ignore)) {
+                if (ignore)
+                        continue;
                 if (max_depth < udev->upper_level)
                         max_depth = udev->upper_level;
         }
@@ -6867,11 +6969,14 @@ static u8 __netdev_lower_depth(struct net_device *dev)
         struct net_device *ldev;
         struct list_head *iter;
         u8 max_depth = 0;
+        bool ignore;
 
         for (iter = &dev->adj_list.lower,
-             ldev = netdev_next_lower_dev(dev, &iter);
+             ldev = __netdev_next_lower_dev(dev, &iter, &ignore);
              ldev;
-             ldev = netdev_next_lower_dev(dev, &iter)) {
+             ldev = __netdev_next_lower_dev(dev, &iter, &ignore)) {
+                if (ignore)
+                        continue;
                 if (max_depth < ldev->lower_level)
                         max_depth = ldev->lower_level;
         }
@@ -7035,6 +7140,7 @@ static int __netdev_adjacent_dev_insert(struct net_device *dev,
         adj->master = master;
         adj->ref_nr = 1;
         adj->private = private;
+        adj->ignore = false;
         dev_hold(adj_dev);
 
         pr_debug("Insert adjacency: dev %s adj_dev %s adj->ref_nr %d; dev_hold on %s\n",
@@ -7185,17 +7291,17 @@ static int __netdev_upper_dev_link(struct net_device *dev,
                 return -EBUSY;
 
         /* To prevent loops, check if dev is not upper device to upper_dev. */
-        if (netdev_has_upper_dev(upper_dev, dev))
+        if (__netdev_has_upper_dev(upper_dev, dev))
                 return -EBUSY;
 
         if ((dev->lower_level + upper_dev->upper_level) > MAX_NEST_DEV)
                 return -EMLINK;
 
         if (!master) {
-                if (netdev_has_upper_dev(dev, upper_dev))
+                if (__netdev_has_upper_dev(dev, upper_dev))
                         return -EEXIST;
         } else {
-                master_dev = netdev_master_upper_dev_get(dev);
+                master_dev = __netdev_master_upper_dev_get(dev);
                 if (master_dev)
                         return master_dev == upper_dev ? -EEXIST : -EBUSY;
         }
@@ -7218,10 +7324,11 @@ static int __netdev_upper_dev_link(struct net_device *dev,
                 goto rollback;
 
         __netdev_update_upper_level(dev, NULL);
-        netdev_walk_all_lower_dev(dev, __netdev_update_upper_level, NULL);
+        __netdev_walk_all_lower_dev(dev, __netdev_update_upper_level, NULL);
 
         __netdev_update_lower_level(upper_dev, NULL);
-        netdev_walk_all_upper_dev(upper_dev, __netdev_update_lower_level, NULL);
+        __netdev_walk_all_upper_dev(upper_dev, __netdev_update_lower_level,
+                                    NULL);
 
         return 0;
 
@@ -7307,13 +7414,94 @@ void netdev_upper_dev_unlink(struct net_device *dev,
                                       &changeupper_info.info);
 
         __netdev_update_upper_level(dev, NULL);
-        netdev_walk_all_lower_dev(dev, __netdev_update_upper_level, NULL);
+        __netdev_walk_all_lower_dev(dev, __netdev_update_upper_level, NULL);
 
         __netdev_update_lower_level(upper_dev, NULL);
-        netdev_walk_all_upper_dev(upper_dev, __netdev_update_lower_level, NULL);
+        __netdev_walk_all_upper_dev(upper_dev, __netdev_update_lower_level,
+                                    NULL);
 }
 EXPORT_SYMBOL(netdev_upper_dev_unlink);
 
+static void __netdev_adjacent_dev_set(struct net_device *upper_dev,
+                                      struct net_device *lower_dev,
+                                      bool val)
+{
+        struct netdev_adjacent *adj;
+
+        adj = __netdev_find_adj(lower_dev, &upper_dev->adj_list.lower);
+        if (adj)
+                adj->ignore = val;
+
+        adj = __netdev_find_adj(upper_dev, &lower_dev->adj_list.upper);
+        if (adj)
+                adj->ignore = val;
+}
+
+static void netdev_adjacent_dev_disable(struct net_device *upper_dev,
+                                        struct net_device *lower_dev)
+{
+        __netdev_adjacent_dev_set(upper_dev, lower_dev, true);
+}
+
+static void netdev_adjacent_dev_enable(struct net_device *upper_dev,
+                                       struct net_device *lower_dev)
+{
+        __netdev_adjacent_dev_set(upper_dev, lower_dev, false);
+}
+
+int netdev_adjacent_change_prepare(struct net_device *old_dev,
+                                   struct net_device *new_dev,
+                                   struct net_device *dev,
+                                   struct netlink_ext_ack *extack)
+{
+        int err;
+
+        if (!new_dev)
+                return 0;
+
+        if (old_dev && new_dev != old_dev)
+                netdev_adjacent_dev_disable(dev, old_dev);
+
+        err = netdev_upper_dev_link(new_dev, dev, extack);
+        if (err) {
+                if (old_dev && new_dev != old_dev)
+                        netdev_adjacent_dev_enable(dev, old_dev);
+                return err;
+        }
+
+        return 0;
+}
+EXPORT_SYMBOL(netdev_adjacent_change_prepare);
+
+void netdev_adjacent_change_commit(struct net_device *old_dev,
+                                   struct net_device *new_dev,
+                                   struct net_device *dev)
+{
+        if (!new_dev || !old_dev)
+                return;
+
+        if (new_dev == old_dev)
+                return;
+
+        netdev_adjacent_dev_enable(dev, old_dev);
+        netdev_upper_dev_unlink(old_dev, dev);
+}
+EXPORT_SYMBOL(netdev_adjacent_change_commit);
+
+void netdev_adjacent_change_abort(struct net_device *old_dev,
+                                  struct net_device *new_dev,
+                                  struct net_device *dev)
+{
+        if (!new_dev)
+                return;
+
+        if (old_dev && new_dev != old_dev)
+                netdev_adjacent_dev_enable(dev, old_dev);
+
+        netdev_upper_dev_unlink(new_dev, dev);
+}
+EXPORT_SYMBOL(netdev_adjacent_change_abort);
+
 /**
  * netdev_bonding_info_change - Dispatch event about slave change
  * @dev: device