net: transition netdev reg state earlier in run_todo

In prep for unregistering netdevs out of order move the netdev
state validation and change outside of the loop.

While at it modernize this code and use WARN() instead of
pr_err() + dump_stack().

Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Xin Long <lucien.xin@gmail.com>
Link: https://lore.kernel.org/r/20220215225310.3679266-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/core/dev.c b/net/core/dev.c
index 909fb381591084a91f7be2da981d813abb5f4b53..2749776e2dd2b82fc8383add7c61d8c5d66b8c04 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -9906,6 +9906,7 @@ static void netdev_wait_allrefs(struct net_device *dev)
  */
 void netdev_run_todo(void)
 {
+       struct net_device *dev, *tmp;
        struct list_head list;
 #ifdef CONFIG_LOCKDEP
        struct list_head unlink_list;
@@ -9926,24 +9927,23 @@ void netdev_run_todo(void)
 
        __rtnl_unlock();
 
-
        /* Wait for rcu callbacks to finish before next phase */
        if (!list_empty(&list))
                rcu_barrier();
 
-       while (!list_empty(&list)) {
-               struct net_device *dev
-                       = list_first_entry(&list, struct net_device, todo_list);
-               list_del(&dev->todo_list);
-
+       list_for_each_entry_safe(dev, tmp, &list, todo_list) {
                if (unlikely(dev->reg_state != NETREG_UNREGISTERING)) {
-                       pr_err("network todo '%s' but state %d\n",
-                              dev->name, dev->reg_state);
-                       dump_stack();
+                       netdev_WARN(dev, "run_todo but not unregistering\n");
+                       list_del(&dev->todo_list);
                        continue;
                }
 
                dev->reg_state = NETREG_UNREGISTERED;
+       }
+
+       while (!list_empty(&list)) {
+               dev = list_first_entry(&list, struct net_device, todo_list);
+               list_del(&dev->todo_list);
 
                netdev_wait_allrefs(dev);