kernel: Backport patch to automatically bring up DSA master when opening user port

Without this patch we have to manually bring up the CPU interface in
failsafe mode.

This was backported from kernel 5.12.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Tested-by: Rafał Miłecki <rafal@milecki.pl>

6 files changed, 97 insertions, 12 deletions

diff --git a/target/linux/generic/backport-5.4/765-v5.12-net-dsa-automatically-bring-up-DSA-master-when-openi.patch b/target/linux/generic/backport-5.4/765-v5.12-net-dsa-automatically-bring-up-DSA-master-when-openi.patch
new file mode 100644
index 0000000000..7ec26899f9
--- /dev/null
+++ b/target/linux/generic/backport-5.4/765-v5.12-net-dsa-automatically-bring-up-DSA-master-when-openi.patch
@@ -0,0 +1,85 @@
+From 9d5ef190e5615a7b63af89f88c4106a5bc127974 Mon Sep 17 00:00:00 2001
+From: Vladimir Oltean <vladimir.oltean@nxp.com>
+Date: Fri, 5 Feb 2021 15:37:10 +0200
+Subject: [PATCH] net: dsa: automatically bring up DSA master when opening user
+ port
+
+DSA wants the master interface to be open before the user port is due to
+historical reasons. The promiscuity of interfaces that are down used to
+have issues, as referenced Lennert Buytenhek in commit df02c6ff2e39
+("dsa: fix master interface allmulti/promisc handling").
+
+The bugfix mentioned there, commit b6c40d68ff64 ("net: only invoke
+dev->change_rx_flags when device is UP"), was basically a "don't do
+that" approach to working around the promiscuity while down issue.
+
+Further work done by Vlad Yasevich in commit d2615bf45069 ("net: core:
+Always propagate flag changes to interfaces") has resolved the
+underlying issue, and it is strictly up to the DSA and 8021q drivers
+now, it is no longer mandated by the networking core that the master
+interface must be up when changing its promiscuity.
+
+From DSA's point of view, deciding to error out in dsa_slave_open
+because the master isn't up is
+(a) a bad user experience and
+(b) knocking at an open door.
+Even if there still was an issue with promiscuity while down, DSA could
+still just open the master and avoid it.
+
+Doing it this way has the additional benefit that user space can now
+remove DSA-specific workarounds, like systemd-networkd with BindCarrier:
+https://github.com/systemd/systemd/issues/7478
+
+And we can finally remove one of the 2 bullets in the "Common pitfalls
+using DSA setups" chapter.
+
+Tested with two cascaded DSA switches:
+
+$ ip link set sw0p2 up
+fsl_enetc 0000:00:00.2 eno2: configuring for fixed/internal link mode
+fsl_enetc 0000:00:00.2 eno2: Link is Up - 1Gbps/Full - flow control rx/tx
+mscc_felix 0000:00:00.5 swp0: configuring for fixed/sgmii link mode
+mscc_felix 0000:00:00.5 swp0: Link is Up - 1Gbps/Full - flow control off
+8021q: adding VLAN 0 to HW filter on device swp0
+sja1105 spi2.0 sw0p2: configuring for phy/rgmii-id link mode
+IPv6: ADDRCONF(NETDEV_CHANGE): eno2: link becomes ready
+IPv6: ADDRCONF(NETDEV_CHANGE): swp0: link becomes ready
+
+Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
+Reviewed-by: Andrew Lunn <andrew@lunn.ch>
+Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
+Signed-off-by: Jakub Kicinski <kuba@kernel.org>
+---
+ Documentation/networking/dsa/dsa.rst | 4 ----
+ net/dsa/slave.c                      | 7 +++++--
+ 2 files changed, 5 insertions(+), 6 deletions(-)
+
+--- a/Documentation/networking/dsa/dsa.rst
++++ b/Documentation/networking/dsa/dsa.rst
+@@ -273,10 +273,6 @@ will not make us go through the switch t
+ the Ethernet switch on the other end, expecting a tag will typically drop this
+ frame.
+ 
+-Slave network devices check that the master network device is UP before allowing
+-you to administratively bring UP these slave network devices. A common
+-configuration mistake is forgetting to bring UP the master network device first.
+-
+ Interactions with other subsystems
+ ==================================
+ 
+--- a/net/dsa/slave.c
++++ b/net/dsa/slave.c
+@@ -70,8 +70,11 @@ static int dsa_slave_open(struct net_dev
+ 	struct dsa_port *dp = dsa_slave_to_port(dev);
+ 	int err;
+ 
+-	if (!(master->flags & IFF_UP))
+-		return -ENETDOWN;
++	err = dev_open(master, NULL);
++	if (err < 0) {
++		netdev_err(dev, "failed to open master %s\n", master->name);
++		goto out;
++	}
+ 
+ 	if (!ether_addr_equal(dev->dev_addr, master->dev_addr)) {
+ 		err = dev_uc_add(master, dev->dev_addr);
diff --git a/target/linux/generic/backport-5.4/771-v5.12-net-dsa-be-louder-when-a-non-legacy-FDB-operation-fa.patch b/target/linux/generic/backport-5.4/771-v5.12-net-dsa-be-louder-when-a-non-legacy-FDB-operation-fa.patch
index 297175855b..9ec1a226b5 100644
--- a/target/linux/generic/backport-5.4/771-v5.12-net-dsa-be-louder-when-a-non-legacy-FDB-operation-fa.patch
+++ b/target/linux/generic/backport-5.4/771-v5.12-net-dsa-be-louder-when-a-non-legacy-FDB-operation-fa.patch
@@ -25,7 +25,7 @@ Signed-off-by: Jakub Kicinski <kuba@kernel.org>
 
 --- a/net/dsa/slave.c
 +++ b/net/dsa/slave.c
-@@ -1592,7 +1592,9 @@ static void dsa_slave_switchdev_event_wo
+@@ -1595,7 +1595,9 @@ static void dsa_slave_switchdev_event_wo
  
  		err = dsa_port_fdb_add(dp, fdb_info->addr, fdb_info->vid);
  		if (err) {
@@ -36,7 +36,7 @@ Signed-off-by: Jakub Kicinski <kuba@kernel.org>
  			break;
  		}
  		fdb_info->offloaded = true;
-@@ -1607,9 +1609,11 @@ static void dsa_slave_switchdev_event_wo
+@@ -1610,9 +1612,11 @@ static void dsa_slave_switchdev_event_wo
  
  		err = dsa_port_fdb_del(dp, fdb_info->addr, fdb_info->vid);
  		if (err) {
diff --git a/target/linux/generic/backport-5.4/772-v5.12-net-dsa-don-t-use-switchdev_notifier_fdb_info-in-dsa.patch b/target/linux/generic/backport-5.4/772-v5.12-net-dsa-don-t-use-switchdev_notifier_fdb_info-in-dsa.patch
index e9b74053e0..bc29fbecc4 100644
--- a/target/linux/generic/backport-5.4/772-v5.12-net-dsa-don-t-use-switchdev_notifier_fdb_info-in-dsa.patch
+++ b/target/linux/generic/backport-5.4/772-v5.12-net-dsa-don-t-use-switchdev_notifier_fdb_info-in-dsa.patch
@@ -54,7 +54,7 @@ Signed-off-by: Jakub Kicinski <kuba@kernel.org>
  	struct sk_buff *	(*xmit)(struct sk_buff *skb,
 --- a/net/dsa/slave.c
 +++ b/net/dsa/slave.c
-@@ -1567,76 +1567,66 @@ static int dsa_slave_netdevice_event(str
+@@ -1570,76 +1570,66 @@ static int dsa_slave_netdevice_event(str
  	return NOTIFY_DONE;
  }
  
@@ -167,7 +167,7 @@ Signed-off-by: Jakub Kicinski <kuba@kernel.org>
  }
  
  /* Called under rcu_read_lock() */
-@@ -1644,7 +1634,9 @@ static int dsa_slave_switchdev_event(str
+@@ -1647,7 +1637,9 @@ static int dsa_slave_switchdev_event(str
  				     unsigned long event, void *ptr)
  {
  	struct net_device *dev = switchdev_notifier_info_to_dev(ptr);
@@ -177,7 +177,7 @@ Signed-off-by: Jakub Kicinski <kuba@kernel.org>
  	int err;
  
  	if (event == SWITCHDEV_PORT_ATTR_SET) {
-@@ -1657,20 +1649,32 @@ static int dsa_slave_switchdev_event(str
+@@ -1660,20 +1652,32 @@ static int dsa_slave_switchdev_event(str
  	if (!dsa_slave_dev_check(dev))
  		return NOTIFY_DONE;
  
@@ -213,7 +213,7 @@ Signed-off-by: Jakub Kicinski <kuba@kernel.org>
  		dev_hold(dev);
  		break;
  	default:
-@@ -1680,10 +1684,6 @@ static int dsa_slave_switchdev_event(str
+@@ -1683,10 +1687,6 @@ static int dsa_slave_switchdev_event(str
  
  	dsa_schedule_work(&switchdev_work->work);
  	return NOTIFY_OK;
diff --git a/target/linux/generic/backport-5.4/773-v5.12-net-dsa-move-switchdev-event-implementation-under-th.patch b/target/linux/generic/backport-5.4/773-v5.12-net-dsa-move-switchdev-event-implementation-under-th.patch
index b46cd7545e..50c7a08590 100644
--- a/target/linux/generic/backport-5.4/773-v5.12-net-dsa-move-switchdev-event-implementation-under-th.patch
+++ b/target/linux/generic/backport-5.4/773-v5.12-net-dsa-move-switchdev-event-implementation-under-th.patch
@@ -20,7 +20,7 @@ Signed-off-by: Jakub Kicinski <kuba@kernel.org>
 
 --- a/net/dsa/slave.c
 +++ b/net/dsa/slave.c
-@@ -1639,31 +1639,29 @@ static int dsa_slave_switchdev_event(str
+@@ -1642,31 +1642,29 @@ static int dsa_slave_switchdev_event(str
  	struct dsa_port *dp;
  	int err;
  
@@ -68,7 +68,7 @@ Signed-off-by: Jakub Kicinski <kuba@kernel.org>
  		fdb_info = ptr;
  
  		if (!fdb_info->added_by_user) {
-@@ -1676,13 +1674,12 @@ static int dsa_slave_switchdev_event(str
+@@ -1679,13 +1677,12 @@ static int dsa_slave_switchdev_event(str
  		switchdev_work->vid = fdb_info->vid;
  
  		dev_hold(dev);
diff --git a/target/linux/generic/backport-5.4/774-v5.12-net-dsa-exit-early-in-dsa_slave_switchdev_event-if-w.patch b/target/linux/generic/backport-5.4/774-v5.12-net-dsa-exit-early-in-dsa_slave_switchdev_event-if-w.patch
index d38c3901cf..dcb6bbdc49 100644
--- a/target/linux/generic/backport-5.4/774-v5.12-net-dsa-exit-early-in-dsa_slave_switchdev_event-if-w.patch
+++ b/target/linux/generic/backport-5.4/774-v5.12-net-dsa-exit-early-in-dsa_slave_switchdev_event-if-w.patch
@@ -30,7 +30,7 @@ Signed-off-by: Jakub Kicinski <kuba@kernel.org>
 
 --- a/net/dsa/slave.c
 +++ b/net/dsa/slave.c
-@@ -1652,6 +1652,9 @@ static int dsa_slave_switchdev_event(str
+@@ -1655,6 +1655,9 @@ static int dsa_slave_switchdev_event(str
  
  		dp = dsa_slave_to_port(dev);
  
diff --git a/target/linux/generic/backport-5.4/775-v5.12-net-dsa-listen-for-SWITCHDEV_-FDB-DEL-_ADD_TO_DEVICE.patch b/target/linux/generic/backport-5.4/775-v5.12-net-dsa-listen-for-SWITCHDEV_-FDB-DEL-_ADD_TO_DEVICE.patch
index 4aa85e5750..b49d11a776 100644
--- a/target/linux/generic/backport-5.4/775-v5.12-net-dsa-listen-for-SWITCHDEV_-FDB-DEL-_ADD_TO_DEVICE.patch
+++ b/target/linux/generic/backport-5.4/775-v5.12-net-dsa-listen-for-SWITCHDEV_-FDB-DEL-_ADD_TO_DEVICE.patch
@@ -172,7 +172,7 @@ Signed-off-by: DENG Qingfang <dqfext@gmail.com>
  	 */
 --- a/net/dsa/slave.c
 +++ b/net/dsa/slave.c
-@@ -1629,6 +1629,25 @@ static void dsa_slave_switchdev_event_wo
+@@ -1632,6 +1632,25 @@ static void dsa_slave_switchdev_event_wo
  		dev_put(dp->slave);
  }
  
@@ -198,7 +198,7 @@ Signed-off-by: DENG Qingfang <dqfext@gmail.com>
  /* Called under rcu_read_lock() */
  static int dsa_slave_switchdev_event(struct notifier_block *unused,
  				     unsigned long event, void *ptr)
-@@ -1647,10 +1666,37 @@ static int dsa_slave_switchdev_event(str
+@@ -1650,10 +1669,37 @@ static int dsa_slave_switchdev_event(str
  		return notifier_from_errno(err);
  	case SWITCHDEV_FDB_ADD_TO_DEVICE:
  	case SWITCHDEV_FDB_DEL_TO_DEVICE:
@@ -239,7 +239,7 @@ Signed-off-by: DENG Qingfang <dqfext@gmail.com>
  
  		if (!dp->ds->ops->port_fdb_add || !dp->ds->ops->port_fdb_del)
  			return NOTIFY_DONE;
-@@ -1665,18 +1711,13 @@ static int dsa_slave_switchdev_event(str
+@@ -1668,18 +1714,13 @@ static int dsa_slave_switchdev_event(str
  		switchdev_work->port = dp->index;
  		switchdev_work->event = event;