Merge branch 'net-Introduce-ndo_get_port_parent_id'

Florian Fainelli says:

====================
net: Introduce ndo_get_port_parent_id()

Based on discussion with Ido and feedback from Jakub there are clearly
two classes of users that implement SWITCHDEV_ATTR_ID_PORT_PARENT_ID:

- PF/VF drivers which typically only implement return the port's parent
  ID, yet have to implement switchdev_port_attr_get() just for that

- Ethernet switch drivers: mlxsw, ocelot, DSA, etc. which implement more
  attributes which we want to be able to eventually veto in the context
  of the caller, thus making them candidates for using a blocking notifier
  chain

Changes in v4:

- remove superfluous net/switchdev.h inclusions in a few files
- added Jiri's Acked-by where given
- removed err = -EOPNOTSUPP initializations
- changed according to Jiri's suggestion in net/ipv4/ipmr.c

Changes in v3:

- keep ethsw's switchdev_ops assignment
- remove inclusion of net/switchdev.h in netdevsim which is no longer
  necesary

Changes in v2:

- resolved build failures spotted by kbuild test robot
- added helpers functions into the core network device layer:
  dev_get_port_parent_id() and netdev_port_same_parent_id();
- added support for recursion to lower devices

Changes from RFC:

- introduce a ndo_get_port_parent_id() and convert all relevant drivers
  to use it

- get rid of SWITCHDEV_ATTR_ID_PORT_PARENT_ID

A subsequent set of patches will convert switchdev_port_attr_set() to
use a blocking notifier call, and still get rid of
switchdev_port_attr_get() altogether.
====================

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

3 files changed, 63 insertions, 18 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index bfa4be42afff..8c6d5cf8a308 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -7878,6 +7878,63 @@ int dev_get_phys_port_name(struct net_device *dev,
 EXPORT_SYMBOL(dev_get_phys_port_name);
 
 /**
+ *	dev_get_port_parent_id - Get the device's port parent identifier
+ *	@dev: network device
+ *	@ppid: pointer to a storage for the port's parent identifier
+ *	@recurse: allow/disallow recursion to lower devices
+ *
+ *	Get the devices's port parent identifier
+ */
+int dev_get_port_parent_id(struct net_device *dev,
+			   struct netdev_phys_item_id *ppid,
+			   bool recurse)
+{
+	const struct net_device_ops *ops = dev->netdev_ops;
+	struct netdev_phys_item_id first = { };
+	struct net_device *lower_dev;
+	struct list_head *iter;
+	int err = -EOPNOTSUPP;
+
+	if (ops->ndo_get_port_parent_id)
+		return ops->ndo_get_port_parent_id(dev, ppid);
+
+	if (!recurse)
+		return err;
+
+	netdev_for_each_lower_dev(dev, lower_dev, iter) {
+		err = dev_get_port_parent_id(lower_dev, ppid, recurse);
+		if (err)
+			break;
+		if (!first.id_len)
+			first = *ppid;
+		else if (memcmp(&first, ppid, sizeof(*ppid)))
+			return -ENODATA;
+	}
+
+	return err;
+}
+EXPORT_SYMBOL(dev_get_port_parent_id);
+
+/**
+ *	netdev_port_same_parent_id - Indicate if two network devices have
+ *	the same port parent identifier
+ *	@a: first network device
+ *	@b: second network device
+ */
+bool netdev_port_same_parent_id(struct net_device *a, struct net_device *b)
+{
+	struct netdev_phys_item_id a_id = { };
+	struct netdev_phys_item_id b_id = { };
+
+	if (dev_get_port_parent_id(a, &a_id, true) ||
+	    dev_get_port_parent_id(b, &b_id, true))
+		return false;
+
+	return netdev_phys_item_id_same(&a_id, &b_id);
+}
+EXPORT_SYMBOL(netdev_port_same_parent_id);
+
+/**
  *	dev_change_proto_down - update protocol port state information
  *	@dev: device
  *	@proto_down: new value
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index ff9fd2bb4ce4..7c5061123ead 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -12,7 +12,6 @@
 #include <linux/capability.h>
 #include <linux/kernel.h>
 #include <linux/netdevice.h>
-#include <net/switchdev.h>
 #include <linux/if_arp.h>
 #include <linux/slab.h>
 #include <linux/sched/signal.h>
@@ -501,16 +500,11 @@ static ssize_t phys_switch_id_show(struct device *dev,
 		return restart_syscall();
 
 	if (dev_isalive(netdev)) {
-		struct switchdev_attr attr = {
-			.orig_dev = netdev,
-			.id = SWITCHDEV_ATTR_ID_PORT_PARENT_ID,
-			.flags = SWITCHDEV_F_NO_RECURSE,
-		};
+		struct netdev_phys_item_id ppid = { };
 
-		ret = switchdev_port_attr_get(netdev, &attr);
+		ret = dev_get_port_parent_id(netdev, &ppid, false);
 		if (!ret)
-			ret = sprintf(buf, "%*phN\n", attr.u.ppid.id_len,
-				      attr.u.ppid.id);
+			ret = sprintf(buf, "%*phN\n", ppid.id_len, ppid.id);
 	}
 	rtnl_unlock();
 
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index f5a98082ac7a..a51cab95ba64 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -46,7 +46,6 @@
 
 #include <linux/inet.h>
 #include <linux/netdevice.h>
-#include <net/switchdev.h>
 #include <net/ip.h>
 #include <net/protocol.h>
 #include <net/arp.h>
@@ -1146,22 +1145,17 @@ static int rtnl_phys_port_name_fill(struct sk_buff *skb, struct net_device *dev)
 
 static int rtnl_phys_switch_id_fill(struct sk_buff *skb, struct net_device *dev)
 {
+	struct netdev_phys_item_id ppid = { };
 	int err;
-	struct switchdev_attr attr = {
-		.orig_dev = dev,
-		.id = SWITCHDEV_ATTR_ID_PORT_PARENT_ID,
-		.flags = SWITCHDEV_F_NO_RECURSE,
-	};
 
-	err = switchdev_port_attr_get(dev, &attr);
+	err = dev_get_port_parent_id(dev, &ppid, false);
 	if (err) {
 		if (err == -EOPNOTSUPP)
 			return 0;
 		return err;
 	}
 
-	if (nla_put(skb, IFLA_PHYS_SWITCH_ID, attr.u.ppid.id_len,
-		    attr.u.ppid.id))
+	if (nla_put(skb, IFLA_PHYS_SWITCH_ID, ppid.id_len, ppid.id))
 		return -EMSGSIZE;
 
 	return 0;