Revert "Revert "can: dev: Move device back to init netns on owning netns delete""

This reverts commit 4ca012d8ea as the kabi
can be updated at this point in time.

Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I5f2d693199b3bf04eb00c0380c4b426c1749f62e

drivers/net/can/dev/dev.c

@@ -1255,6 +1255,7 @@ static void can_dellink(struct net_device *dev, struct list_head *head)
 
 static struct rtnl_link_ops can_link_ops __read_mostly = {
 	.kind		= "can",
+	.netns_refund	= true,
 	.maxtype	= IFLA_CAN_MAX,
 	.policy		= can_policy,
 	.setup		= can_setup,

include/net/rtnetlink.h

@@ -33,6 +33,7 @@ static inline int rtnl_msg_family(const struct nlmsghdr *nlh)
  *
  *	@list: Used internally
  *	@kind: Identifier
+ *	@netns_refund: Physical device, move to init_net on netns exit
  *	@maxtype: Highest device specific netlink attribute number
  *	@policy: Netlink policy for device specific attribute validation
  *	@validate: Optional validation function for netlink/changelink parameters
@@ -64,6 +65,7 @@ struct rtnl_link_ops {
 	size_t			priv_size;
 	void			(*setup)(struct net_device *dev);
 
+	bool			netns_refund;
 	unsigned int		maxtype;
 	const struct nla_policy	*policy;
 	int			(*validate)(struct nlattr *tb[],

net/core/dev.c

@@ -11106,7 +11106,7 @@ static void __net_exit default_device_exit(struct net *net)
 			continue;
 
 		/* Leave virtual devices for the generic cleanup */
-		if (dev->rtnl_link_ops)
+		if (dev->rtnl_link_ops && !dev->rtnl_link_ops->netns_refund)
 			continue;
 
 		/* Push remaining network devices to init_net */