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-rw-r--r--fs/sysfs/file.c54
1 files changed, 54 insertions, 0 deletions
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index 8d4d839a9d8..1bafdf6e171 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -629,6 +629,60 @@ void sysfs_remove_file_from_group(struct kobject *kobj,
}
EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group);
+struct sysfs_schedule_callback_struct {
+ struct kobject *kobj;
+ void (*func)(void *);
+ void *data;
+ struct work_struct work;
+};
+
+static void sysfs_schedule_callback_work(struct work_struct *work)
+{
+ struct sysfs_schedule_callback_struct *ss = container_of(work,
+ struct sysfs_schedule_callback_struct, work);
+
+ (ss->func)(ss->data);
+ kobject_put(ss->kobj);
+ kfree(ss);
+}
+
+/**
+ * sysfs_schedule_callback - helper to schedule a callback for a kobject
+ * @kobj: object we're acting for.
+ * @func: callback function to invoke later.
+ * @data: argument to pass to @func.
+ *
+ * sysfs attribute methods must not unregister themselves or their parent
+ * kobject (which would amount to the same thing). Attempts to do so will
+ * deadlock, since unregistration is mutually exclusive with driver
+ * callbacks.
+ *
+ * Instead methods can call this routine, which will attempt to allocate
+ * and schedule a workqueue request to call back @func with @data as its
+ * argument in the workqueue's process context. @kobj will be pinned
+ * until @func returns.
+ *
+ * Returns 0 if the request was submitted, -ENOMEM if storage could not
+ * be allocated.
+ */
+int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *),
+ void *data)
+{
+ struct sysfs_schedule_callback_struct *ss;
+
+ ss = kmalloc(sizeof(*ss), GFP_KERNEL);
+ if (!ss)
+ return -ENOMEM;
+ kobject_get(kobj);
+ ss->kobj = kobj;
+ ss->func = func;
+ ss->data = data;
+ INIT_WORK(&ss->work, sysfs_schedule_callback_work);
+ schedule_work(&ss->work);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(sysfs_schedule_callback);
+
EXPORT_SYMBOL_GPL(sysfs_create_file);
EXPORT_SYMBOL_GPL(sysfs_remove_file);