[PATCH] Driver core: link device and all class devices derived from it.

Driver core: link device and all class devices derived from it.

To ease the task of locating class devices derived from a certain
device create symlinks from parent device to its class devices.
Change USB host class device name from usbX to usb_hostX to avoid
conflict when creating aforementioned links.

Tweaked by Greg to have the symlink be "class_name:class_device_name" in
order to prevent duplicate links.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/base/class.c b/drivers/base/class.c
index 0154a16..d207296 100644 (file)
--- a/drivers/base/class.c
+++ b/drivers/base/class.c
@@ -452,10 +452,29 @@ void class_device_initialize(struct class_device *class_dev)
        INIT_LIST_HEAD(&class_dev->node);
 }
 
+static char *make_class_name(struct class_device *class_dev)
+{
+       char *name;
+       int size;
+
+       size = strlen(class_dev->class->name) +
+               strlen(kobject_name(&class_dev->kobj)) + 2;
+
+       name = kmalloc(size, GFP_KERNEL);
+       if (!name)
+               return ERR_PTR(-ENOMEM);
+
+       strcpy(name, class_dev->class->name);
+       strcat(name, ":");
+       strcat(name, kobject_name(&class_dev->kobj));
+       return name;
+}
+
 int class_device_add(struct class_device *class_dev)
 {
        struct class * parent = NULL;
        struct class_interface * class_intf;
+       char *class_name = NULL;
        int error;
 
        class_dev = class_device_get(class_dev);
@@ -500,9 +519,13 @@ int class_device_add(struct class_device *class_dev)
        }
 
        class_device_add_attrs(class_dev);
-       if (class_dev->dev)
+       if (class_dev->dev) {
+               class_name = make_class_name(class_dev);
                sysfs_create_link(&class_dev->kobj,
                                  &class_dev->dev->kobj, "device");
+               sysfs_create_link(&class_dev->dev->kobj, &class_dev->kobj,
+                                 class_name);
+       }
 
        /* notify any interfaces this device is now here */
        if (parent) {
@@ -519,6 +542,7 @@ int class_device_add(struct class_device *class_dev)
        if (error && parent)
                class_put(parent);
        class_device_put(class_dev);
+       kfree(class_name);
        return error;
 }
 
@@ -584,6 +608,7 @@ void class_device_del(struct class_device *class_dev)
 {
        struct class * parent = class_dev->class;
        struct class_interface * class_intf;
+       char *class_name = NULL;
 
        if (parent) {
                down(&parent->sem);
@@ -594,8 +619,11 @@ void class_device_del(struct class_device *class_dev)
                up(&parent->sem);
        }
 
-       if (class_dev->dev)
+       if (class_dev->dev) {
+               class_name = make_class_name(class_dev);
                sysfs_remove_link(&class_dev->kobj, "device");
+               sysfs_remove_link(&class_dev->dev->kobj, class_name);
+       }
        if (class_dev->devt_attr)
                class_device_remove_file(class_dev, class_dev->devt_attr);
        class_device_remove_attrs(class_dev);
@@ -605,6 +633,7 @@ void class_device_del(struct class_device *class_dev)
 
        if (parent)
                class_put(parent);
+       kfree(class_name);
 }
 
 void class_device_unregister(struct class_device *class_dev)

diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 79422a3..9f44e83 100644 (file)
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -782,7 +782,7 @@ static int usb_register_bus(struct usb_bus *bus)
                return -E2BIG;
        }
 
-       bus->class_dev = class_device_create(usb_host_class, MKDEV(0,0), bus->controller, "usb%d", busnum);
+       bus->class_dev = class_device_create(usb_host_class, MKDEV(0,0), bus->controller, "usb_host%d", busnum);
        if (IS_ERR(bus->class_dev)) {
                clear_bit(busnum, busmap.busmap);
                up(&usb_bus_list_lock);