[RFC][PATCH -mm take5 4/7] using symlink for the net_device

From: Keiichi KII
Date: Wed Jun 13 2007 - 06:29:34 EST


From: Keiichi KII <k-keiichi@xxxxxxxxxxxxx>

We use symbolic link for net_device.
The link in sysfs represents the corresponding network etherdevice.

-+- /sys/class/misc/
|-+- netconsole/
|-+- port1/
| |--- id [r--r--r--] id
| |--- net:<net_dev> [r--r--r--] net_dev: eth0,eth1,...
| ...
|--- port2/
...

Signed-off-by: Keiichi KII <k-keiichi@xxxxxxxxxxxxx>
Signed-off-by: Takayoshi Kochi <t-kochi@xxxxxxxxxxxxx>
---
Index: mm/drivers/net/netconsole.c
===================================================================
--- mm.orig/drivers/net/netconsole.c
+++ mm/drivers/net/netconsole.c
@@ -76,6 +76,7 @@ struct netconsole_target {

static LIST_HEAD(target_list);
static DEFINE_SPINLOCK(target_list_lock);
+static DECLARE_MUTEX(netdev_change_sem);

static int miscdev_configured;

@@ -239,12 +240,14 @@ static void remove_target(struct netcons
{
unsigned long flags;

+ down(&netdev_change_sem);
spin_lock_irqsave(&target_list_lock, flags);
list_del(&nt->list);
if (list_empty(&target_list))
netpoll_cleanup(&nt->np);
spin_unlock_irqrestore(&target_list_lock, flags);
kfree(nt);
+ up(&netdev_change_sem);
}

static void release_target(struct kobject *kobj)
@@ -271,12 +274,35 @@ static struct kobj_type target_ktype = {
.default_attrs = target_attrs,
};

+static char *make_netdev_class_name(char *netdev_name)
+{
+ char *name;
+
+ name = kasprintf(GFP_KERNEL, "net:%s", netdev_name);
+ if (!name) {
+ printk(KERN_ERR "netconsole: kmalloc() failed!\n");
+ return NULL;
+ }
+
+ return name;
+}
+
static int setup_target_sysfs(struct netconsole_target *nt)
{
+ int retval = 0;
+ char *name;
+
kobject_set_name(&nt->obj, "port%d", nt->id);
nt->obj.parent = &netconsole_miscdev.this_device->kobj;
nt->obj.ktype = &target_ktype;
- return kobject_register(&nt->obj);
+ retval = kobject_register(&nt->obj);
+ name = make_netdev_class_name(nt->np.dev_name);
+ if (!name)
+ return -ENOMEM;
+ retval = sysfs_create_link(&nt->obj, &nt->np.dev->dev.kobj, name);
+ kfree(name);
+
+ return retval;
}

static int add_target(char* target_config)
@@ -323,6 +349,60 @@ static int add_target(char* target_confi
out:
return retval;
}
+
+static int netconsole_event(struct notifier_block *this, unsigned long event,
+ void *ptr)
+{
+ int error = 0;
+ unsigned long flags;
+ char *old_link_name = NULL, *new_link_name = NULL;
+ struct netconsole_target *nt, *tmp;
+ struct net_device *dev = ptr;
+ LIST_HEAD(modify_target_list);
+
+ if (event == NETDEV_CHANGENAME) {
+ spin_lock_irqsave(&target_list_lock, flags);
+ list_for_each_entry_safe(nt, tmp, &target_list, list)
+ if (nt->np.dev == dev)
+ list_move(&nt->list, &modify_target_list);
+ spin_unlock_irqrestore(&target_list_lock, flags);
+
+ down(&netdev_change_sem);
+ list_for_each_entry(nt, &modify_target_list, list) {
+ new_link_name = make_netdev_class_name(dev->name);
+ old_link_name = make_netdev_class_name(nt->np.dev_name);
+ if (!new_link_name || !old_link_name) {
+ printk(KERN_ERR "netconsole: "
+ "make_netdev_class_name() failed!\n");
+ kfree(new_link_name);
+ kfree(old_link_name);
+ continue;
+ }
+ sysfs_remove_link(&nt->obj, old_link_name);
+ error = sysfs_create_link(&nt->obj,
+ &nt->np.dev->dev.kobj,
+ new_link_name);
+ if (error)
+ printk(KERN_ERR "can't create link: %s\n",
+ new_link_name);
+ strcpy(nt->np.dev_name, dev->name);
+ kfree(new_link_name);
+ kfree(old_link_name);
+ }
+ up(&netdev_change_sem);
+
+ spin_lock_irqsave(&target_list_lock, flags);
+ list_for_each_entry_safe(nt, tmp, &modify_target_list, list)
+ list_move(&nt->list, &target_list);
+ spin_unlock_irqrestore(&target_list_lock, flags);
+ }
+
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block netconsole_notifier = {
+ .notifier_call = netconsole_event,
+};
#endif /* CONFIG_NETCONSOLE_DYNCON */

static void write_msg(struct console *con, const char *msg, unsigned int len)
@@ -387,6 +467,7 @@ static void cleanup_netconsole(void)
unregister_console(&netconsole);
list_for_each_entry_safe(nt, tmp, &target_list, list)
kobject_unregister(&nt->obj);
+ unregister_netdevice_notifier(&netconsole_notifier);
if (miscdev_configured)
misc_deregister(&netconsole_miscdev);
#else
@@ -410,6 +491,7 @@ static int __init init_netconsole(void)
} else
miscdev_configured = 1;

+ register_netdevice_notifier(&netconsole_notifier);
register_console(&netconsole);
if (!strlen(config)) {
printk(KERN_ERR "netconsole: not configured\n");

--


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