[openwrt/openwrt] kernel: backport switchdev fix for bridge in bridge configurations

[LEDE Commits]

hauke pushed a commit to openwrt/openwrt.git, branch openwrt-21.02:
https://git.openwrt.org/c37a9e506c6e53c80fe37a8eb7ac435eb966fa76

commit c37a9e506c6e53c80fe37a8eb7ac435eb966fa76
Author: Fabian Bläse <fabian at blaese.de>
AuthorDate: Sun Aug 29 21:21:35 2021 +0200

    kernel: backport switchdev fix for bridge in bridge configurations
    
    This patch fixes the forwarding behavior of bridge in bridge
    configurations with DSA.
    
    Without it, the configuration of the upper bridge might overwrite
    settings of the lower bridge. For example, a vlan-aware bridge
    with DSA interfaces in it might be offloaded to the DSA hardware. If the
    bridge interface itself gets slave of a different bridge without vlan
    filtering, the vlan filtering setting of the lower bridge is overwritten
    by the upper bridge, which results in an incorrect hardware
    configuration.
    
    This was backported from kernel 5.7.
    
    Ref: https://lore.kernel.org/netdev/20191222192235.GK25745@shell.armlinux.org.uk/
    Fixes: FS#3996
    Signed-off-by: Fabian Bläse <fabian at blaese.de>
    (cherry picked from commit c50ece58c41647880cc74c927d98b465cdfbdad8)
---
 ...ev-do-not-propagate-bridge-updates-across.patch | 60 ++++++++++++++++++++++
 1 file changed, 60 insertions(+)

diff --git a/target/linux/generic/backport-5.4/790-v5.7-net-switchdev-do-not-propagate-bridge-updates-across.patch b/target/linux/generic/backport-5.4/790-v5.7-net-switchdev-do-not-propagate-bridge-updates-across.patch
new file mode 100644
index 0000000000..bc8014b772
--- /dev/null
+++ b/target/linux/generic/backport-5.4/790-v5.7-net-switchdev-do-not-propagate-bridge-updates-across.patch
@@ -0,0 +1,60 @@
+From 07c6f9805f12f1bb538ef165a092b300350384aa Mon Sep 17 00:00:00 2001
+From: Russell King <rmk+kernel at armlinux.org.uk>
+Date: Wed, 26 Feb 2020 17:14:21 +0000
+Subject: [PATCH] net: switchdev: do not propagate bridge updates across
+ bridges
+
+When configuring a tree of independent bridges, propagating changes
+from the upper bridge across a bridge master to the lower bridge
+ports brings surprises.
+
+For example, a lower bridge may have vlan filtering enabled.  It
+may have a vlan interface attached to the bridge master, which may
+then be incorporated into another bridge.  As soon as the lower
+bridge vlan interface is attached to the upper bridge, the lower
+bridge has vlan filtering disabled.
+
+This occurs because switchdev recursively applies its changes to
+all lower devices no matter what.
+
+Reviewed-by: Ido Schimmel <idosch at mellanox.com>
+Tested-by: Ido Schimmel <idosch at mellanox.com>
+Signed-off-by: Russell King <rmk+kernel at armlinux.org.uk>
+Reviewed-by: Florian Fainelli <f.fainelli at gmail.com>
+Signed-off-by: David S. Miller <davem at davemloft.net>
+---
+ net/switchdev/switchdev.c | 9 +++++++++
+ 1 file changed, 9 insertions(+)
+
+--- a/net/switchdev/switchdev.c
++++ b/net/switchdev/switchdev.c
+@@ -476,6 +476,9 @@ static int __switchdev_handle_port_obj_a
+ 	 * necessary to go through this helper.
+ 	 */
+ 	netdev_for_each_lower_dev(dev, lower_dev, iter) {
++		if (netif_is_bridge_master(lower_dev))
++			continue;
++
+ 		err = __switchdev_handle_port_obj_add(lower_dev, port_obj_info,
+ 						      check_cb, add_cb);
+ 		if (err && err != -EOPNOTSUPP)
+@@ -528,6 +531,9 @@ static int __switchdev_handle_port_obj_d
+ 	 * necessary to go through this helper.
+ 	 */
+ 	netdev_for_each_lower_dev(dev, lower_dev, iter) {
++		if (netif_is_bridge_master(lower_dev))
++			continue;
++
+ 		err = __switchdev_handle_port_obj_del(lower_dev, port_obj_info,
+ 						      check_cb, del_cb);
+ 		if (err && err != -EOPNOTSUPP)
+@@ -579,6 +585,9 @@ static int __switchdev_handle_port_attr_
+ 	 * necessary to go through this helper.
+ 	 */
+ 	netdev_for_each_lower_dev(dev, lower_dev, iter) {
++		if (netif_is_bridge_master(lower_dev))
++			continue;
++
+ 		err = __switchdev_handle_port_attr_set(lower_dev, port_attr_info,
+ 						       check_cb, set_cb);
+ 		if (err && err != -EOPNOTSUPP)