This is a prep commit to convert ipmr_net_exit_batch() to
->exit_rtnl().

Let's move unregister_netdevice_many() in ipmr_free_table()
to its callers.

Now ipmr_rules_exit() can do batching all tables per netns.

Note that later we will remove RTNL and unregister_netdevice_many()
in ipmr_rules_init().

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
---
 net/ipv4/ipmr.c | 25 +++++++++++++++++--------
 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index f8bbb88f5784..3fb50307fc2f 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -102,7 +102,8 @@ static DEFINE_SPINLOCK(mfc_unres_lock);
 static struct kmem_cache *mrt_cachep __ro_after_init;
 
 static struct mr_table *ipmr_new_table(struct net *net, u32 id);
-static void ipmr_free_table(struct mr_table *mrt);
+static void ipmr_free_table(struct mr_table *mrt,
+			    struct list_head *dev_kill_list);
 
 static void ip_mr_forward(struct net *net, struct mr_table *mrt,
 			  struct net_device *dev, struct sk_buff *skb,
@@ -251,6 +252,7 @@ static const struct fib_rules_ops __net_initconst ipmr_rules_ops_template = {
 static int __net_init ipmr_rules_init(struct net *net)
 {
 	struct fib_rules_ops *ops;
+	LIST_HEAD(dev_kill_list);
 	struct mr_table *mrt;
 	int err;
 
@@ -275,7 +277,8 @@ static int __net_init ipmr_rules_init(struct net *net)
 
 err2:
 	rtnl_lock();
-	ipmr_free_table(mrt);
+	ipmr_free_table(mrt, &dev_kill_list);
+	unregister_netdevice_many(&dev_kill_list);
 	rtnl_unlock();
 err1:
 	fib_rules_unregister(ops);
@@ -285,12 +288,15 @@ static int __net_init ipmr_rules_init(struct net *net)
 static void __net_exit ipmr_rules_exit(struct net *net)
 {
 	struct mr_table *mrt, *next;
+	LIST_HEAD(dev_kill_list);
 
 	ASSERT_RTNL();
 	list_for_each_entry_safe(mrt, next, &net->ipv4.mr_tables, list) {
 		list_del(&mrt->list);
-		ipmr_free_table(mrt);
+		ipmr_free_table(mrt, &dev_kill_list);
 	}
+
+	unregister_netdevice_many(&dev_kill_list);
 	fib_rules_unregister(net->ipv4.mr_rules_ops);
 }
 
@@ -349,8 +355,13 @@ static int __net_init ipmr_rules_init(struct net *net)
 
 static void __net_exit ipmr_rules_exit(struct net *net)
 {
+	LIST_HEAD(dev_kill_list);
+
 	ASSERT_RTNL();
-	ipmr_free_table(net->ipv4.mrt);
+
+	ipmr_free_table(net->ipv4.mrt, &dev_kill_list);
+	unregister_netdevice_many(&dev_kill_list);
+
 	net->ipv4.mrt = NULL;
 }
 
@@ -425,18 +436,16 @@ static struct mr_table *ipmr_new_table(struct net *net, u32 id)
 			      ipmr_expire_process, ipmr_new_table_set);
 }
 
-static void ipmr_free_table(struct mr_table *mrt)
+static void ipmr_free_table(struct mr_table *mrt, struct list_head *dev_kill_list)
 {
 	struct net *net = read_pnet(&mrt->net);
-	LIST_HEAD(dev_kill_list);
 
 	WARN_ON_ONCE(!mr_can_free_table(net));
 
 	timer_shutdown_sync(&mrt->ipmr_expire_timer);
 	mroute_clean_tables(mrt, MRT_FLUSH_VIFS | MRT_FLUSH_VIFS_STATIC |
 			    MRT_FLUSH_MFC | MRT_FLUSH_MFC_STATIC,
-			    &dev_kill_list);
-	unregister_netdevice_many(&dev_kill_list);
+			    dev_kill_list);
 	rhltable_destroy(&mrt->mfc_hash);
 	kfree(mrt);
 }
-- 
2.53.0.414.gf7e9f6c205-goog