[PATCH] (1/8) hdlc wan device disembedding

[PATCH] (1/8) hdlc wan device disembedding

[Stephen Hemminger]

Change the hdlc wan device's to not have the net_device structure embedded
inside the hdlc_device structure.  This won't work on 2.6 where the net_device
structure may need to live after module unload due to sysfs.
Instead, use alloc_netdev and setup so that netdev->priv = hdlc 
and have hdlc->dev_data for device private data.

Patch is against net-drivers-2.5-exp tree.  This portion breaks the actual
hardware drivers but that is fixed in parts 2-5. I don't have any of this hardware
so the code has only been tested by compiling and loading the modules.

# This is a BitKeeper generated patch for the following project:
# Project Name: Linux kernel tree
# This patch format is intended for GNU patch command version 2.5 or higher.
# This patch includes the following deltas:
#	           ChangeSet	1.1502  -> 1.1503 
#	drivers/net/wan/hdlc_generic.c	1.14    -> 1.15   
#	drivers/net/wan/hdlc_cisco.c	1.9     -> 1.10   
#	drivers/net/wan/hdlc_fr.c	1.9     -> 1.10   
#	include/linux/hdlc.h	1.10    -> 1.11   
#
# The following is the BitKeeper ChangeSet Log
# --------------------------------------------
# 03/12/01	shemminger@osdl.org	1.1503
# 1-hdlc_device
# --------------------------------------------
#
diff -Nru a/drivers/net/wan/hdlc_cisco.c b/drivers/net/wan/hdlc_cisco.c
--- a/drivers/net/wan/hdlc_cisco.c	Mon Dec  1 14:45:08 2003
+++ b/drivers/net/wan/hdlc_cisco.c	Mon Dec  1 14:45:08 2003
@@ -222,8 +222,8 @@
 	    hdlc->state.cisco.settings.timeout * HZ) {
 		hdlc->state.cisco.up = 0;
 		printk(KERN_INFO "%s: Link down\n", hdlc_to_name(hdlc));
-		if (netif_carrier_ok(&hdlc->netdev))
-			netif_carrier_off(&hdlc->netdev);
+		if (netif_carrier_ok(hdlc->netdev))
+			netif_carrier_off(hdlc->netdev);
 	}
 
 	cisco_keepalive_send(hdlc, CISCO_KEEPALIVE_REQ,
@@ -256,8 +256,8 @@
 static void cisco_stop(hdlc_device *hdlc)
 {
 	del_timer_sync(&hdlc->state.cisco.timer);
-	if (netif_carrier_ok(&hdlc->netdev))
-		netif_carrier_off(&hdlc->netdev);
+	if (netif_carrier_ok(hdlc->netdev))
+		netif_carrier_off(hdlc->netdev);
 }
 
 
diff -Nru a/drivers/net/wan/hdlc_fr.c b/drivers/net/wan/hdlc_fr.c
--- a/drivers/net/wan/hdlc_fr.c	Mon Dec  1 14:45:08 2003
+++ b/drivers/net/wan/hdlc_fr.c	Mon Dec  1 14:45:08 2003
@@ -543,8 +543,8 @@
 
 	hdlc->state.fr.reliable = reliable;
 	if (reliable) {
-		if (!netif_carrier_ok(&hdlc->netdev))
-			netif_carrier_on(&hdlc->netdev);
+		if (!netif_carrier_ok(hdlc->netdev))
+			netif_carrier_on(hdlc->netdev);
 
 		hdlc->state.fr.n391cnt = 0; /* Request full status */
 		hdlc->state.fr.dce_changed = 1;
@@ -558,8 +558,8 @@
 			}
 		}
 	} else {
-		if (netif_carrier_ok(&hdlc->netdev))
-			netif_carrier_off(&hdlc->netdev);
+		if (netif_carrier_ok(hdlc->netdev))
+			netif_carrier_off(hdlc->netdev);
 
 		while (pvc) {		/* Deactivate all PVCs */
 			pvc_carrier(0, pvc);
@@ -938,8 +938,8 @@
 	printk(KERN_DEBUG "fr_start\n");
 #endif
 	if (hdlc->state.fr.settings.lmi != LMI_NONE) {
-		if (netif_carrier_ok(&hdlc->netdev))
-			netif_carrier_off(&hdlc->netdev);
+		if (netif_carrier_ok(hdlc->netdev))
+			netif_carrier_off(hdlc->netdev);
 		hdlc->state.fr.last_poll = 0;
 		hdlc->state.fr.reliable = 0;
 		hdlc->state.fr.dce_changed = 1;
diff -Nru a/drivers/net/wan/hdlc_generic.c b/drivers/net/wan/hdlc_generic.c
--- a/drivers/net/wan/hdlc_generic.c	Mon Dec  1 14:45:08 2003
+++ b/drivers/net/wan/hdlc_generic.c	Mon Dec  1 14:45:08 2003
@@ -71,6 +71,7 @@
 
 void hdlc_set_carrier(int on, hdlc_device *hdlc)
 {
+	struct net_device *dev = hdlc_to_dev(hdlc);
 	on = on ? 1 : 0;
 
 #ifdef DEBUG_LINK
@@ -92,14 +93,14 @@
 	if (hdlc->carrier) {
 		if (hdlc->proto.start)
 			hdlc->proto.start(hdlc);
-		else if (!netif_carrier_ok(&hdlc->netdev))
-			netif_carrier_on(&hdlc->netdev);
+		else if (!netif_carrier_ok(dev))
+			netif_carrier_on(dev);
 
 	} else { /* no carrier */
 		if (hdlc->proto.stop)
 			hdlc->proto.stop(hdlc);
-		else if (netif_carrier_ok(&hdlc->netdev))
-			netif_carrier_off(&hdlc->netdev);
+		else if (netif_carrier_ok(dev))
+			netif_carrier_off(dev);
 	}
 
  carrier_exit:
@@ -110,6 +111,8 @@
 /* Must be called by hardware driver when HDLC device is being opened */
 int hdlc_open(hdlc_device *hdlc)
 {
+	struct net_device *dev = hdlc_to_dev(hdlc);
+
 #ifdef DEBUG_LINK
 	printk(KERN_DEBUG "hdlc_open carrier %i open %i\n",
 	       hdlc->carrier, hdlc->open);
@@ -129,11 +132,11 @@
 	if (hdlc->carrier) {
 		if (hdlc->proto.start)
 			hdlc->proto.start(hdlc);
-		else if (!netif_carrier_ok(&hdlc->netdev))
-			netif_carrier_on(&hdlc->netdev);
+		else if (!netif_carrier_ok(dev))
+			netif_carrier_on(dev);
 
-	} else if (netif_carrier_ok(&hdlc->netdev))
-		netif_carrier_off(&hdlc->netdev);
+	} else if (netif_carrier_ok(dev))
+		netif_carrier_off(dev);
 
 	hdlc->open = 1;
 
@@ -224,11 +227,9 @@
 }
 
 
-
-int register_hdlc_device(hdlc_device *hdlc)
+static void hdlc_setup(struct net_device *dev)
 {
-	int result;
-	struct net_device *dev = hdlc_to_dev(hdlc);
+	hdlc_device *hdlc = dev->priv;
 
 	dev->get_stats = hdlc_get_stats;
 	dev->change_mtu = hdlc_change_mtu;
@@ -245,17 +246,13 @@
 	hdlc->open = 0;
 	spin_lock_init(&hdlc->state_lock);
 
-	result = dev_alloc_name(dev, "hdlc%d");
-	if (result < 0)
-		return result;
-
-	result = register_netdev(dev);
-	if (result != 0)
-		return -EIO;
-
-	return 0;
+	hdlc->dev_data = (hdlc + 1);
 }
 
+int register_hdlc_device(hdlc_device *hdlc)
+{
+	return register_netdev(hdlc_to_dev(hdlc));
+}
 
 
 void unregister_hdlc_device(hdlc_device *hdlc)
@@ -266,7 +263,17 @@
 	rtnl_unlock();
 }
 
+hdlc_device *alloc_hdlc_device(int sizeof_priv)
+{
+	struct net_device *dev = alloc_netdev(sizeof_priv + sizeof(hdlc_device),
+					      "hdlc%d", hdlc_setup);
+	return dev ? dev_to_hdlc(dev) : NULL;
+}
 
+void free_hdlc_device(hdlc_device *hdlc)
+{
+	free_netdev(hdlc_to_dev(hdlc));
+}
 
 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
 MODULE_DESCRIPTION("HDLC support module");
@@ -278,6 +285,8 @@
 EXPORT_SYMBOL(hdlc_ioctl);
 EXPORT_SYMBOL(register_hdlc_device);
 EXPORT_SYMBOL(unregister_hdlc_device);
+EXPORT_SYMBOL(alloc_hdlc_device);
+EXPORT_SYMBOL(free_hdlc_device);
 
 static struct packet_type hdlc_packet_type = {
 	.type = __constant_htons(ETH_P_HDLC),
diff -Nru a/include/linux/hdlc.h b/include/linux/hdlc.h
--- a/include/linux/hdlc.h	Mon Dec  1 14:45:08 2003
+++ b/include/linux/hdlc.h	Mon Dec  1 14:45:08 2003
@@ -96,7 +96,9 @@
 
 typedef struct hdlc_device_struct {
 	/* To be initialized by hardware driver */
-	struct net_device netdev; /* master net device - must be first */
+	struct net_device *netdev; 	/* master net device */
+	void  *dev_data;
+
 	struct net_device_stats stats;
 
 	/* used by HDLC layer to take control over HDLC device from hw driver*/
@@ -180,6 +182,8 @@
 
 
 /* Exported from hdlc.o */
+hdlc_device *alloc_hdlc_device(int sizeof_priv);
+void free_hdlc_device(hdlc_device *hdlc);
 
 /* Called by hardware driver when a user requests HDLC service */
 int hdlc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd);
@@ -188,18 +192,15 @@
 int register_hdlc_device(hdlc_device *hdlc);
 void unregister_hdlc_device(hdlc_device *hdlc);
 
-
 static __inline__ struct net_device* hdlc_to_dev(hdlc_device *hdlc)
 {
-	return &hdlc->netdev;
+	return hdlc->netdev;
 }
 
-
-static __inline__ hdlc_device* dev_to_hdlc(struct net_device *dev)
+static __inline__ hdlc_device *dev_to_hdlc(struct net_device *dev)
 {
-	return (hdlc_device*)dev;
+	return dev->priv;
 }
-
 
 static __inline__ pvc_device* dev_to_pvc(struct net_device *dev)
 {

Re: [PATCH] (1/8) hdlc wan device disembedding

[Krzysztof Halasa]

Stephen Hemminger <shemminger@osdl.org> writes:

> Change the hdlc wan device's to not have the net_device structure embedded
> inside the hdlc_device structure.  This won't work on 2.6 where the
> net_device
> structure may need to live after module unload due to sysfs.
> Instead, use alloc_netdev and setup so that netdev->priv = hdlc 
> and have hdlc->dev_data for device private data.

Hmm... I always wanted dev->priv to be available for hw drivers (and
yes, PPP proto doesn't currently meet that).

Any other idea maybe?


It seems the whole WAN (drivers/net/wan) needs some major rewrite, as
the recent patches (starting with last 2.5.x ones) have broken few
things (at least for me) which are not all fixed.

First I would duplicate syncppp.c code in hdlc_ppp.c (removing Cisco HDLC
support and polishing it to suit generic HDLC needs) so it no longer
depends on syncppp (long-term I plan switching to generic PPP but it's
certainly post-2.6 thing and I'm not even sure how to do it).
This would result in few hundred lines of duplicated code, though.

The positive side is that I can test the generic HDLC + hw drivers for
C101, N2, wanXL, PCI200SYN (being merged) and PC300.


The other thing would be converting drivers using syncppp.c to use
generic HDLC instead (it would add support for X.25, Frame-Relay and
raw HDLC). While I can probably make a patch I can't test it.

The remaining drivers use either Sangoma (sdla/dlci/wanpipe/wanrouter)
or comx code. Not sure about their status, are they both maintained?

Comments?
-- 
Krzysztof Halasa, B*FH