WAN: HDLC: Call notifiers before and after changing device type

An HDLC device can change type when the protocol driver is changed.
Calling the notifier change allows potential users of the interface
know about this planned change, and even block it. After the change
has occurred, send a second notification to users can evaluate the new
device type etc.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

8 files changed, 24 insertions, 3 deletions

diff --git a/drivers/net/wan/hdlc.c b/drivers/net/wan/hdlc.c
index 2a6595b..9bd4aa8 100644
--- a/drivers/net/wan/hdlc.c
+++ b/drivers/net/wan/hdlc.c
@@ -276,7 +276,11 @@ void unregister_hdlc_device(struct net_device *dev)
 int attach_hdlc_protocol(struct net_device *dev, struct hdlc_proto *proto,
 			 size_t size)
 {
-	detach_hdlc_protocol(dev);
+	int err;
+
+	err = detach_hdlc_protocol(dev);
+	if (err)
+		return err;
 
 	if (!try_module_get(proto->module))
 		return -ENOSYS;
@@ -289,15 +293,24 @@ int attach_hdlc_protocol(struct net_device *dev, struct hdlc_proto *proto,
 		}
 	}
 	dev_to_hdlc(dev)->proto = proto;
+
 	return 0;
 }
 
 
-void detach_hdlc_protocol(struct net_device *dev)
+int detach_hdlc_protocol(struct net_device *dev)
 {
 	hdlc_device *hdlc = dev_to_hdlc(dev);
+	int err;
 
 	if (hdlc->proto) {
+		err = call_netdevice_notifiers(NETDEV_PRE_TYPE_CHANGE, dev);
+		err = notifier_to_errno(err);
+		if (err) {
+			netdev_err(dev, "Refused to change device type\n");
+			return err;
+		}
+
 		if (hdlc->proto->detach)
 			hdlc->proto->detach(dev);
 		module_put(hdlc->proto->module);
@@ -306,6 +319,8 @@ void detach_hdlc_protocol(struct net_device *dev)
 	kfree(hdlc->state);
 	hdlc->state = NULL;
 	hdlc_setup_dev(dev);
+
+	return 0;
 }
 
 
diff --git a/drivers/net/wan/hdlc_cisco.c b/drivers/net/wan/hdlc_cisco.c
index 3f20808..a408abc 100644
--- a/drivers/net/wan/hdlc_cisco.c
+++ b/drivers/net/wan/hdlc_cisco.c
@@ -378,6 +378,7 @@ static int cisco_ioctl(struct net_device *dev, struct ifreq *ifr)
 		spin_lock_init(&state(hdlc)->lock);
 		dev->header_ops = &cisco_header_ops;
 		dev->type = ARPHRD_CISCO;
+		call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, dev);
 		netif_dormant_on(dev);
 		return 0;
 	}
diff --git a/drivers/net/wan/hdlc_fr.c b/drivers/net/wan/hdlc_fr.c
index 89541cc..b6e0cfb 100644
--- a/drivers/net/wan/hdlc_fr.c
+++ b/drivers/net/wan/hdlc_fr.c
@@ -1240,6 +1240,7 @@ static int fr_ioctl(struct net_device *dev, struct ifreq *ifr)
 		}
 		memcpy(&state(hdlc)->settings, &new_settings, size);
 		dev->type = ARPHRD_FRAD;
+		call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, dev);
 		return 0;
 
 	case IF_PROTO_FR_ADD_PVC:
diff --git a/drivers/net/wan/hdlc_ppp.c b/drivers/net/wan/hdlc_ppp.c
index 0d76455..47fdb87 100644
--- a/drivers/net/wan/hdlc_ppp.c
+++ b/drivers/net/wan/hdlc_ppp.c
@@ -687,6 +687,7 @@ static int ppp_ioctl(struct net_device *dev, struct ifreq *ifr)
 		dev->hard_header_len = sizeof(struct hdlc_header);
 		dev->header_ops = &ppp_header_ops;
 		dev->type = ARPHRD_PPP;
+		call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, dev);
 		netif_dormant_on(dev);
 		return 0;
 	}
diff --git a/drivers/net/wan/hdlc_raw.c b/drivers/net/wan/hdlc_raw.c
index 5dc153e..4feb450 100644
--- a/drivers/net/wan/hdlc_raw.c
+++ b/drivers/net/wan/hdlc_raw.c
@@ -84,6 +84,7 @@ static int raw_ioctl(struct net_device *dev, struct ifreq *ifr)
 			return result;
 		memcpy(hdlc->state, &new_settings, size);
 		dev->type = ARPHRD_RAWHDLC;
+		call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, dev);
 		netif_dormant_off(dev);
 		return 0;
 	}
diff --git a/drivers/net/wan/hdlc_raw_eth.c b/drivers/net/wan/hdlc_raw_eth.c
index 3ab72b3..2f11836 100644
--- a/drivers/net/wan/hdlc_raw_eth.c
+++ b/drivers/net/wan/hdlc_raw_eth.c
@@ -102,6 +102,7 @@ static int raw_eth_ioctl(struct net_device *dev, struct ifreq *ifr)
 		ether_setup(dev);
 		dev->tx_queue_len = old_qlen;
 		eth_hw_addr_random(dev);
+		call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, dev);
 		netif_dormant_off(dev);
 		return 0;
 	}
diff --git a/drivers/net/wan/hdlc_x25.c b/drivers/net/wan/hdlc_x25.c
index a49aec5..e867638 100644
--- a/drivers/net/wan/hdlc_x25.c
+++ b/drivers/net/wan/hdlc_x25.c
@@ -213,6 +213,7 @@ static int x25_ioctl(struct net_device *dev, struct ifreq *ifr)
 		if ((result = attach_hdlc_protocol(dev, &proto, 0)))
 			return result;
 		dev->type = ARPHRD_X25;
+		call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, dev);
 		netif_dormant_off(dev);
 		return 0;
 	}
diff --git a/include/linux/hdlc.h b/include/linux/hdlc.h
index 1acb144..e31bcd4 100644
--- a/include/linux/hdlc.h
+++ b/include/linux/hdlc.h
@@ -101,7 +101,7 @@ netdev_tx_t hdlc_start_xmit(struct sk_buff *skb, struct net_device *dev);
 int attach_hdlc_protocol(struct net_device *dev, struct hdlc_proto *proto,
 			 size_t size);
 /* May be used by hardware driver to gain control over HDLC device */
-void detach_hdlc_protocol(struct net_device *dev);
+int detach_hdlc_protocol(struct net_device *dev);
 
 static __inline__ __be16 hdlc_type_trans(struct sk_buff *skb,
 					 struct net_device *dev)