[net-next,v5,1/4] net core: Add protodown support.

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index e20979d..99ebb01 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1041,6 +1041,11 @@  typedef u16 (*select_queue_fallback_t)(struct net_device *dev,
  *	TX queue.
  * int (*ndo_get_iflink)(const struct net_device *dev);
  *	Called to get the iflink value of this device.
+ * void (*ndo_change_proto_flags)(struct net_device *dev,
+ *				  unsigned int proto_flags);
+ *	This function is used to pass protocol port state information
+ *	to the switch driver.
+ *
  */
 struct net_device_ops {
 	int			(*ndo_init)(struct net_device *dev);
@@ -1211,6 +1216,8 @@  struct net_device_ops {
 						      int queue_index,
 						      u32 maxrate);
 	int			(*ndo_get_iflink)(const struct net_device *dev);
+	int			(*ndo_change_proto_flags)(struct net_device *dev,
+							  unsigned int proto_flags);
 };
 
 /**
@@ -1502,6 +1509,10 @@  enum netdev_priv_flags {
  *
  *	@qdisc_tx_busylock:	XXX: need comments on this one
  *
+ *	@proto_flags:	protocol port state information can be sent to the
+ *			switch driver and used to set the phys state of the
+ *			switch port.
+ *
  *	FIXME: cleanup struct net_device such that network protocol info
  *	moves out.
  */
@@ -1762,6 +1773,7 @@  struct net_device {
 #endif
 	struct phy_device *phydev;
 	struct lock_class_key *qdisc_tx_busylock;
+	unsigned int proto_flags;
 };
 #define to_net_dev(d) container_of(d, struct net_device, dev)
 
@@ -2982,6 +2994,7 @@  int dev_get_phys_port_id(struct net_device *dev,
 			 struct netdev_phys_item_id *ppid);
 int dev_get_phys_port_name(struct net_device *dev,
 			   char *name, size_t len);
+int dev_change_proto_flags(struct net_device *dev, unsigned int proto_flags);
 struct sk_buff *validate_xmit_skb_list(struct sk_buff *skb, struct net_device *dev);
 struct sk_buff *dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev,
 				    struct netdev_queue *txq, int *ret);
diff --git a/include/uapi/linux/if.h b/include/uapi/linux/if.h
index 9cf2394..8d60fe7 100644
--- a/include/uapi/linux/if.h
+++ b/include/uapi/linux/if.h
@@ -156,6 +156,12 @@  enum {
 	IF_LINK_MODE_DORMANT,	/* limit upward transition to dormant */
 };
 
+/* proto_flags - port state information can be passed to the switch driver and
+ * used to determine the phys state of the switch port */
+enum {
+	IF_PROTOF_DOWN		= 1<<0	/* set switch port phys state down */
+};
+
 /*
  *	Device mapping structure. I'd just gone off and designed a 
  *	beautiful scheme using only loadable modules with arguments
diff --git a/net/core/dev.c b/net/core/dev.c
index 6778a99..87571c4 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6076,6 +6076,26 @@  int dev_get_phys_port_name(struct net_device *dev,
 EXPORT_SYMBOL(dev_get_phys_port_name);
 
 /**
+ *	dev_change_proto_flags - update protocol port state information
+ *	@dev: device
+ *	@proto_flags: new value
+ *
+ *	This info can be used by switch drivers to set the phys state of the
+ *	port.
+ */
+int dev_change_proto_flags(struct net_device *dev, unsigned int proto_flags)
+{
+	const struct net_device_ops *ops = dev->netdev_ops;
+
+	if (dev->proto_flags == proto_flags)
+		return 0;
+	if (!ops->ndo_change_proto_flags)
+		return -EOPNOTSUPP;
+	return ops->ndo_change_proto_flags(dev, proto_flags);
+}
+EXPORT_SYMBOL(dev_change_proto_flags);
+
+/**
  *	dev_new_index	-	allocate an ifindex
  *	@net: the applicable net namespace
  *
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 18b34d7..06f355e 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -404,6 +404,19 @@  static ssize_t group_store(struct device *dev, struct device_attribute *attr,
 NETDEVICE_SHOW(group, fmt_dec);
 static DEVICE_ATTR(netdev_group, S_IRUGO | S_IWUSR, group_show, group_store);
 
+static int change_proto_flags(struct net_device *dev, unsigned long proto_flags)
+{
+	return dev_change_proto_flags(dev, (unsigned int)proto_flags);
+}
+
+static ssize_t proto_flags_store(struct device *dev,
+				 struct device_attribute *attr,
+				 const char *buf, size_t len)
+{
+	return netdev_store(dev, attr, buf, len, change_proto_flags);
+}
+NETDEVICE_SHOW_RW(proto_flags, fmt_hex);
+
 static ssize_t phys_port_id_show(struct device *dev,
 				 struct device_attribute *attr, char *buf)
 {
@@ -501,6 +514,7 @@  static struct attribute *net_class_attrs[] = {
 	&dev_attr_phys_port_id.attr,
 	&dev_attr_phys_port_name.attr,
 	&dev_attr_phys_switch_id.attr,
+	&dev_attr_proto_flags.attr,
 	NULL,
 };
 ATTRIBUTE_GROUPS(net_class);