device_schedule_callback() needs a module reference

[safe/jmp/linux-2.6] / fs / sysfs / file.c

diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index fc46333..db0413a 100644 (file)
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -633,6 +633,7 @@ struct sysfs_schedule_callback_struct {
        struct kobject          *kobj;
        void                    (*func)(void *);
        void                    *data;
+       struct module           *owner;
        struct work_struct      work;
 };
 
@@ -643,6 +644,7 @@ static void sysfs_schedule_callback_work(struct work_struct *work)
 
        (ss->func)(ss->data);
        kobject_put(ss->kobj);
+       module_put(ss->owner);
        kfree(ss);
 }
 
@@ -651,6 +653,7 @@ static void sysfs_schedule_callback_work(struct work_struct *work)
  * @kobj: object we're acting for.
  * @func: callback function to invoke later.
  * @data: argument to pass to @func.
+ * @owner: module owning the callback code
  *
  * sysfs attribute methods must not unregister themselves or their parent
  * kobject (which would amount to the same thing).  Attempts to do so will
@@ -663,20 +666,25 @@ static void sysfs_schedule_callback_work(struct work_struct *work)
  * until @func returns.
  *
  * Returns 0 if the request was submitted, -ENOMEM if storage could not
- * be allocated.
+ * be allocated, -ENODEV if a reference to @owner isn't available.
  */
 int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *),
-               void *data)
+               void *data, struct module *owner)
 {
        struct sysfs_schedule_callback_struct *ss;
 
+       if (!try_module_get(owner))
+               return -ENODEV;
        ss = kmalloc(sizeof(*ss), GFP_KERNEL);
-       if (!ss)
+       if (!ss) {
+               module_put(owner);
                return -ENOMEM;
+       }
        kobject_get(kobj);
        ss->kobj = kobj;
        ss->func = func;
        ss->data = data;
+       ss->owner = owner;
        INIT_WORK(&ss->work, sysfs_schedule_callback_work);
        schedule_work(&ss->work);
        return 0;