put "device" symlink into hotplug environment?

[Kay Sievers <kay.sievers@vrfy.org>]

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Hi Greg,
what if we put the sysfs path of the physical device into the hotplug
environment? All virtual devices will not have the key. This would solve
all the wait for the "device" link issues and we can throw away one of
the exception lists as the kernel will tell us if it is going to create
a symlink.

I get hotplug events like this now:

physical backed device:
  ACTION=add
  SUBSYSTEM=net
  DEVPATH=/class/net/eth0
  DEVSYSDEV=/devices/pci0000:00/0000:00:1e.0/0000:02:01.0
  INTERFACE=eth0
  SEQNUM=966
  PATH=/sbin:/bin:/usr/sbin:/usr/bin
  HOME=/

virtual:
  ACTION=add
  SUBSYSTEM=net
  DEVPATH=/class/net/dummy0
  INTERFACE=dummy0
  SEQNUM=977
  PATH=/sbin:/bin:/usr/sbin:/usr/bin
  HOME=/

The current patch is only for class-devices block-devices are not covered.

Thanks,
Kay

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===== drivers/base/class.c 1.54 vs edited =====
--- 1.54/drivers/base/class.c	2004-10-08 20:32:52 +02:00
+++ edited/drivers/base/class.c	2004-11-04 00:23:56 +01:00
@@ -283,8 +283,27 @@ static int class_hotplug(struct kset *ks
 {
 	struct class_device *class_dev = to_class_dev(kobj);
 	int retval = 0;
+	int i = 0;
+	int length = 0;
 
 	pr_debug("%s - name = %s\n", __FUNCTION__, class_dev->class_id);
+
+	if (class_dev->dev) {
+		/* add physical device backing this class to environment */
+		char *dev = kobject_get_path(&class_dev->dev->kobj, GFP_KERNEL);
+
+		add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size,
+				    &length, "DEVSYSDEV=%s", dev);
+		kfree(dev);
+
+		/* terminate, set to next free slot, shrink available space */
+		envp[i] = NULL;
+		envp = &envp[i];
+		num_envp -= i;
+		buffer = &buffer[length];
+		buffer_size -= length;
+	}
+
 	if (class_dev->class->hotplug) {
 		/* have the bus specific function add its stuff */
 		retval = class_dev->class->hotplug (class_dev, envp, num_envp,