[PATCH] Allow multiple dummy devices again

[Andi Kleen <ak@muc.de>]

In 2.6 the old trick of copying the dummy module to get multiple dummy
devices doesn't work anymore because the "dummy" device name is embedded
in the module. 

This patch adds a new module option that allows to specify how many
dummy devices you want.

-Andi

diff -u linux/drivers/net/dummy.c-o linux-2.6.0test11-amd64/drivers/net/dummy.c
--- linux/drivers/net/dummy.c-o	2003-09-11 04:12:33.000000000 +0200
+++ linux/drivers/net/dummy.c	2003-11-28 01:40:47.000000000 +0100
@@ -34,6 +34,8 @@
 #include <linux/netdevice.h>
 #include <linux/init.h>
 
+static int numdummies = 1;
+
 static int dummy_xmit(struct sk_buff *skb, struct net_device *dev);
 static struct net_device_stats *dummy_get_stats(struct net_device *dev);
 
@@ -83,10 +85,14 @@
 	return dev->priv;
 }
 
-static struct net_device *dev_dummy;
+static struct net_device **dummies;
 
-static int __init dummy_init_module(void)
+/* Number of dummy devices to be set up by this module. */
+MODULE_PARM(numdummies, "i")
+
+static int __init dummy_init_one(int index)
 {
+	struct net_device *dev_dummy;
 	int err;
 
 	dev_dummy = alloc_netdev(sizeof(struct net_device_stats),
@@ -98,15 +104,40 @@
 	if ((err = register_netdev(dev_dummy))) {
 		kfree(dev_dummy);
 		dev_dummy = NULL;
+	} else {
+		dummies[index] = dev_dummy; 
 	}
+
 	return err;
 }
 
+static void __exit dummy_free_one(int index) 
+{
+	unregister_netdev(dummies[index]);
+	free_netdev(dummies[index]);
+} 
+
+static int __init dummy_init_module(void)
+{ 
+	int i, err = 0;
+	dummies = kmalloc(numdummies * sizeof(void *), GFP_KERNEL); 
+	if (!dummies)
+		return -ENOMEM; 
+	for (i = 0; i < numdummies && !err; i++)
+		err = dummy_init_one(i); 
+	if (err) { 
+		while (--i >= 0)
+			dummy_free_one(i);
+	}
+	return err;
+} 
+
 static void __exit dummy_cleanup_module(void)
 {
-	unregister_netdev(dev_dummy);
-	free_netdev(dev_dummy);
-	dev_dummy = NULL;
+	int i;
+	for (i = 0; i < numdummies; i++) 
+		dummy_free_one(i); 
+	kfree(dummies);	
 }
 
 module_init(dummy_init_module);