Merge branch 'Pass-extack-to-SWITCHDEV_PORT_OBJ_ADD'

Petr Machata says:

====================
Pass extack to SWITCHDEV_PORT_OBJ_ADD

Drivers may need to do validation as a result of port object addition.
An example is mlxsw, which needs to check the configuration of a VXLAN
device attached to an offloaded bridge. Without a mapped VLAN, the
invalidity of the device is not important, but as soon as a pvid,
untagged VLAN is configured for the device, it has to be validated and
offloaded. Should the validation fail, there's currently no way to
communicate details of the failure to the user, beyond an error number.

Because currently, extack is not available at all in that area of code,
this patch starts down at the RTNL level and progresses up towards the
driver(s).

In patch #1, ndo_bridge_setlink is updated to include extack, and
callbacks of all clients are updated as well (ignoring the argument).

In patch #2, the bridge driver is updated to propagate the extack
through to the switchdev border, br_switchdev_port_vlan_add().

Patches #3, #4 and #5 then gradually extend switchdev to pass the extack
argument through to the switchdev blocking notifier chain.

Patches #6 and #7 then update mlxsw to pass the extack argument from
VXLAN events resp. port events on to mlxsw_sp_bridge_8021q_vxlan_join().

Finally in patches #8 and #9, the code paths from the previous two
patches are verified to yield an error message.

v2:
- Patch #1:
    - In ndo_bridge_setlink(), keep the whole extack declaration on the
      same line.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 25 insertions, 13 deletions

diff --git a/net/switchdev/switchdev.c b/net/switchdev/switchdev.c
index fe23fac4dc4b..5df9d1138ac9 100644
--- a/net/switchdev/switchdev.c
+++ b/net/switchdev/switchdev.c
@@ -356,7 +356,8 @@ static size_t switchdev_obj_size(const struct switchdev_obj *obj)
 static int switchdev_port_obj_notify(enum switchdev_notifier_type nt,
 				     struct net_device *dev,
 				     const struct switchdev_obj *obj,
-				     struct switchdev_trans *trans)
+				     struct switchdev_trans *trans,
+				     struct netlink_ext_ack *extack)
 {
 	int rc;
 	int err;
@@ -367,7 +368,7 @@ static int switchdev_port_obj_notify(enum switchdev_notifier_type nt,
 		.handled = false,
 	};
 
-	rc = call_switchdev_blocking_notifiers(nt, dev, &obj_info.info);
+	rc = call_switchdev_blocking_notifiers(nt, dev, &obj_info.info, extack);
 	err = notifier_to_errno(rc);
 	if (err) {
 		WARN_ON(!obj_info.handled);
@@ -379,7 +380,8 @@ static int switchdev_port_obj_notify(enum switchdev_notifier_type nt,
 }
 
 static int switchdev_port_obj_add_now(struct net_device *dev,
-				      const struct switchdev_obj *obj)
+				      const struct switchdev_obj *obj,
+				      struct netlink_ext_ack *extack)
 {
 	struct switchdev_trans trans;
 	int err;
@@ -397,7 +399,7 @@ static int switchdev_port_obj_add_now(struct net_device *dev,
 
 	trans.ph_prepare = true;
 	err = switchdev_port_obj_notify(SWITCHDEV_PORT_OBJ_ADD,
-					dev, obj, &trans);
+					dev, obj, &trans, extack);
 	if (err) {
 		/* Prepare phase failed: abort the transaction.  Any
 		 * resources reserved in the prepare phase are
@@ -417,7 +419,7 @@ static int switchdev_port_obj_add_now(struct net_device *dev,
 
 	trans.ph_prepare = false;
 	err = switchdev_port_obj_notify(SWITCHDEV_PORT_OBJ_ADD,
-					dev, obj, &trans);
+					dev, obj, &trans, extack);
 	WARN(err, "%s: Commit of object (id=%d) failed.\n", dev->name, obj->id);
 	switchdev_trans_items_warn_destroy(dev, &trans);
 
@@ -430,7 +432,7 @@ static void switchdev_port_obj_add_deferred(struct net_device *dev,
 	const struct switchdev_obj *obj = data;
 	int err;
 
-	err = switchdev_port_obj_add_now(dev, obj);
+	err = switchdev_port_obj_add_now(dev, obj, NULL);
 	if (err && err != -EOPNOTSUPP)
 		netdev_err(dev, "failed (err=%d) to add object (id=%d)\n",
 			   err, obj->id);
@@ -460,12 +462,13 @@ static int switchdev_port_obj_add_defer(struct net_device *dev,
  *	in case SWITCHDEV_F_DEFER flag is not set.
  */
 int switchdev_port_obj_add(struct net_device *dev,
-			   const struct switchdev_obj *obj)
+			   const struct switchdev_obj *obj,
+			   struct netlink_ext_ack *extack)
 {
 	if (obj->flags & SWITCHDEV_F_DEFER)
 		return switchdev_port_obj_add_defer(dev, obj);
 	ASSERT_RTNL();
-	return switchdev_port_obj_add_now(dev, obj);
+	return switchdev_port_obj_add_now(dev, obj, extack);
 }
 EXPORT_SYMBOL_GPL(switchdev_port_obj_add);
 
@@ -473,7 +476,7 @@ static int switchdev_port_obj_del_now(struct net_device *dev,
 				      const struct switchdev_obj *obj)
 {
 	return switchdev_port_obj_notify(SWITCHDEV_PORT_OBJ_DEL,
-					 dev, obj, NULL);
+					 dev, obj, NULL, NULL);
 }
 
 static void switchdev_port_obj_del_deferred(struct net_device *dev,
@@ -556,6 +559,7 @@ int call_switchdev_notifiers(unsigned long val, struct net_device *dev,
 			     struct switchdev_notifier_info *info)
 {
 	info->dev = dev;
+	info->extack = NULL;
 	return atomic_notifier_call_chain(&switchdev_notif_chain, val, info);
 }
 EXPORT_SYMBOL_GPL(call_switchdev_notifiers);
@@ -577,9 +581,11 @@ int unregister_switchdev_blocking_notifier(struct notifier_block *nb)
 EXPORT_SYMBOL_GPL(unregister_switchdev_blocking_notifier);
 
 int call_switchdev_blocking_notifiers(unsigned long val, struct net_device *dev,
-				      struct switchdev_notifier_info *info)
+				      struct switchdev_notifier_info *info,
+				      struct netlink_ext_ack *extack)
 {
 	info->dev = dev;
+	info->extack = extack;
 	return blocking_notifier_call_chain(&switchdev_blocking_notif_chain,
 					    val, info);
 }
@@ -610,16 +616,21 @@ static int __switchdev_handle_port_obj_add(struct net_device *dev,
 			bool (*check_cb)(const struct net_device *dev),
 			int (*add_cb)(struct net_device *dev,
 				      const struct switchdev_obj *obj,
-				      struct switchdev_trans *trans))
+				      struct switchdev_trans *trans,
+				      struct netlink_ext_ack *extack))
 {
+	struct netlink_ext_ack *extack;
 	struct net_device *lower_dev;
 	struct list_head *iter;
 	int err = -EOPNOTSUPP;
 
+	extack = switchdev_notifier_info_to_extack(&port_obj_info->info);
+
 	if (check_cb(dev)) {
 		/* This flag is only checked if the return value is success. */
 		port_obj_info->handled = true;
-		return add_cb(dev, port_obj_info->obj, port_obj_info->trans);
+		return add_cb(dev, port_obj_info->obj, port_obj_info->trans,
+			      extack);
 	}
 
 	/* Switch ports might be stacked under e.g. a LAG. Ignore the
@@ -644,7 +655,8 @@ int switchdev_handle_port_obj_add(struct net_device *dev,
 			bool (*check_cb)(const struct net_device *dev),
 			int (*add_cb)(struct net_device *dev,
 				      const struct switchdev_obj *obj,
-				      struct switchdev_trans *trans))
+				      struct switchdev_trans *trans,
+				      struct netlink_ext_ack *extack))
 {
 	int err;