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

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

As a bonus, mrtsock_destruct() can do batching for all tables.

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
---
 net/ipv4/ipmr.c | 34 ++++++++++++++++++++++++----------
 1 file changed, 24 insertions(+), 10 deletions(-)

diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 3af6b3d33cc8..f8bbb88f5784 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -112,7 +112,8 @@ static int ipmr_cache_report(const struct mr_table *mrt,
 static void mroute_netlink_event(struct mr_table *mrt, struct mfc_cache *mfc,
 				 int cmd);
 static void igmpmsg_netlink_event(const struct mr_table *mrt, struct sk_buff *pkt);
-static void mroute_clean_tables(struct mr_table *mrt, int flags);
+static void mroute_clean_tables(struct mr_table *mrt, int flags,
+				struct list_head *dev_kill_list);
 static void ipmr_expire_process(struct timer_list *t);
 
 #ifdef CONFIG_IP_MROUTE_MULTIPLE_TABLES
@@ -427,12 +428,15 @@ static struct mr_table *ipmr_new_table(struct net *net, u32 id)
 static void ipmr_free_table(struct mr_table *mrt)
 {
 	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);
+			    MRT_FLUSH_MFC | MRT_FLUSH_MFC_STATIC,
+			    &dev_kill_list);
+	unregister_netdevice_many(&dev_kill_list);
 	rhltable_destroy(&mrt->mfc_hash);
 	kfree(mrt);
 }
@@ -1293,12 +1297,12 @@ static int ipmr_mfc_add(struct net *net, struct mr_table *mrt,
 }
 
 /* Close the multicast socket, and clear the vif tables etc */
-static void mroute_clean_tables(struct mr_table *mrt, int flags)
+static void mroute_clean_tables(struct mr_table *mrt, int flags,
+				struct list_head *dev_kill_list)
 {
 	struct net *net = read_pnet(&mrt->net);
-	struct mr_mfc *c, *tmp;
 	struct mfc_cache *cache;
-	LIST_HEAD(list);
+	struct mr_mfc *c, *tmp;
 	int i;
 
 	/* Shut down all active vif entries */
@@ -1308,9 +1312,8 @@ static void mroute_clean_tables(struct mr_table *mrt, int flags)
 			     !(flags & MRT_FLUSH_VIFS_STATIC)) ||
 			    (!(mrt->vif_table[i].flags & VIFF_STATIC) && !(flags & MRT_FLUSH_VIFS)))
 				continue;
-			vif_delete(mrt, i, 0, &list);
+			vif_delete(mrt, i, 0, dev_kill_list);
 		}
-		unregister_netdevice_many(&list);
 	}
 
 	/* Wipe the cache */
@@ -1349,9 +1352,11 @@ static void mroute_clean_tables(struct mr_table *mrt, int flags)
 static void mrtsock_destruct(struct sock *sk)
 {
 	struct net *net = sock_net(sk);
+	LIST_HEAD(dev_kill_list);
 	struct mr_table *mrt;
 
 	rtnl_lock();
+
 	ipmr_for_each_table(mrt, net) {
 		if (sk == rtnl_dereference(mrt->mroute_sk)) {
 			IPV4_DEVCONF_ALL(net, MC_FORWARDING)--;
@@ -1360,9 +1365,13 @@ static void mrtsock_destruct(struct sock *sk)
 						    NETCONFA_IFINDEX_ALL,
 						    net->ipv4.devconf_all);
 			RCU_INIT_POINTER(mrt->mroute_sk, NULL);
-			mroute_clean_tables(mrt, MRT_FLUSH_VIFS | MRT_FLUSH_MFC);
+			mroute_clean_tables(mrt, MRT_FLUSH_VIFS | MRT_FLUSH_MFC,
+					    &dev_kill_list);
 		}
 	}
+
+	unregister_netdevice_many(&dev_kill_list);
+
 	rtnl_unlock();
 }
 
@@ -1485,7 +1494,9 @@ int ip_mroute_setsockopt(struct sock *sk, int optname, sockptr_t optval,
 					   sk == rtnl_dereference(mrt->mroute_sk),
 					   parent);
 		break;
-	case MRT_FLUSH:
+	case MRT_FLUSH: {
+		LIST_HEAD(dev_kill_list);
+
 		if (optlen != sizeof(val)) {
 			ret = -EINVAL;
 			break;
@@ -1494,8 +1505,11 @@ int ip_mroute_setsockopt(struct sock *sk, int optname, sockptr_t optval,
 			ret = -EFAULT;
 			break;
 		}
-		mroute_clean_tables(mrt, val);
+
+		mroute_clean_tables(mrt, val, &dev_kill_list);
+		unregister_netdevice_many(&dev_kill_list);
 		break;
+	}
 	/* Control PIM assert. */
 	case MRT_ASSERT:
 		if (optlen != sizeof(val)) {
-- 
2.53.0.414.gf7e9f6c205-goog