+static loff_t kernfs_fop_llseek(struct file *file, loff_t offset, int whence)
+{
+ struct kernfs_open_file *of = kernfs_of(file);
+ const struct kernfs_ops *ops;
+ loff_t ret;
+
+ /*
+ * @of->mutex nests outside active ref and is primarily to ensure that
+ * the ops aren't called concurrently for the same open file.
+ */
+ mutex_lock(&of->mutex);
+ if (!kernfs_get_active(of->kn)) {
+ mutex_unlock(&of->mutex);
+ return -ENODEV;
+ }
+
+ ops = kernfs_ops(of->kn);
+ if (ops->llseek)
+ ret = ops->llseek(of, offset, whence);
+ else
+ ret = generic_file_llseek(file, offset, whence);
+
+ kernfs_put_active(of->kn);
+ mutex_unlock(&of->mutex);
+ return ret;
+}
+