[PATCH net-next 2/6] net: dsa: hold instance lock on close-on-shutdown paths

[Stanislav Fomichev <sdf.kernel@gmail.com>]

netif_close_many will soon assert ops lock (for locked DOWN/GOING_DOWN).
Update dsa_switch_shutdown to manually grab and release the ops lock.

Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
---
 net/dsa/dsa.c  | 20 +++++++++++++++++---
 net/dsa/user.c | 19 +++++++++++++++++--
 2 files changed, 34 insertions(+), 5 deletions(-)

diff --git a/net/dsa/dsa.c b/net/dsa/dsa.c
index 9cb732f6b1e3..da53a666d4b8 100644
--- a/net/dsa/dsa.c
+++ b/net/dsa/dsa.c
@@ -18,6 +18,7 @@
 #include <linux/of.h>
 #include <linux/of_net.h>
 #include <net/dsa_stubs.h>
+#include <net/netdev_lock.h>
 #include <net/sch_generic.h>
 
 #include "conduit.h"
@@ -1620,10 +1621,23 @@ void dsa_switch_shutdown(struct dsa_switch *ds)
 
 	rtnl_lock();
 
-	dsa_switch_for_each_cpu_port(dp, ds)
-		list_add(&dp->conduit->close_list, &close_list);
+	dsa_switch_for_each_cpu_port(dp, ds) {
+		if (!(dp->conduit->flags & IFF_UP))
+			continue;
+		list_add_tail(&dp->conduit->close_list, &close_list);
+		netdev_lock_ops(dp->conduit);
+	}
+
+	netif_close_many(&close_list, false);
 
-	netif_close_many(&close_list, true);
+	while (!list_empty(&close_list)) {
+		struct net_device *conduit;
+
+		conduit = list_first_entry(&close_list, struct net_device,
+					   close_list);
+		netdev_unlock_ops(conduit);
+		list_del_init(&conduit->close_list);
+	}
 
 	dsa_switch_for_each_user_port(dp, ds) {
 		conduit = dsa_port_to_conduit(dp);
diff --git a/net/dsa/user.c b/net/dsa/user.c
index 8704c1a3a5b7..8ea47444d6d5 100644
--- a/net/dsa/user.c
+++ b/net/dsa/user.c
@@ -13,6 +13,7 @@
 #include <linux/of_net.h>
 #include <linux/of_mdio.h>
 #include <linux/mdio.h>
+#include <net/netdev_lock.h>
 #include <net/rtnetlink.h>
 #include <net/pkt_cls.h>
 #include <net/selftests.h>
@@ -3600,10 +3601,24 @@ static int dsa_user_netdevice_event(struct notifier_block *nb,
 			if (dp->cpu_dp != cpu_dp)
 				continue;
 
-			list_add(&dp->user->close_list, &close_list);
+			if (!(dp->user->flags & IFF_UP))
+				continue;
+
+			list_add_tail(&dp->user->close_list, &close_list);
+			netdev_lock_ops(dp->user);
 		}
 
-		netif_close_many(&close_list, true);
+		netif_close_many(&close_list, false);
+
+		while (!list_empty(&close_list)) {
+			struct net_device *user_dev;
+
+			user_dev = list_first_entry(&close_list,
+						    struct net_device,
+						    close_list);
+			netdev_unlock_ops(user_dev);
+			list_del_init(&user_dev->close_list);
+		}
 
 		return NOTIFY_OK;
 	}
-- 
2.53.0-Meta