fanotify: Move locking inside get_one_event()

 * Get an fsnotify notification event if one exists and is small

 * enough to fit in "count". Return an error pointer if the count

 * is not large enough.

 *

 * Called with the group->notification_lock held.

 */

static struct fsnotify_event *get_one_event(struct fsnotify_group *group,

					    size_t count)

{

	size_t event_size = FAN_EVENT_METADATA_LEN;

	struct fanotify_event *event;

	assert_spin_locked(&group->notification_lock);

	struct fsnotify_event *fsn_event = NULL;

	pr_debug("%s: group=%p count=%zd\n", __func__, group, count);

	spin_lock(&group->notification_lock);

	if (fsnotify_notify_queue_is_empty(group))

		return NULL;

		goto out;

	if (FAN_GROUP_FLAG(group, FAN_REPORT_FID)) {

		event = FANOTIFY_E(fsnotify_peek_first_event(group));

		event_size += fanotify_event_info_len(event);

		event_size += fanotify_event_info_len(

			FANOTIFY_E(fsnotify_peek_first_event(group)));

	}

	if (event_size > count)

		return ERR_PTR(-EINVAL);

	/*

	 * Held the notification_lock the whole time, so this is the

	 * same event we peeked above

	 */

	return fsnotify_remove_first_event(group);

	if (event_size > count) {

		fsn_event = ERR_PTR(-EINVAL);

		goto out;

	}

	fsn_event = fsnotify_remove_first_event(group);

out:

	spin_unlock(&group->notification_lock);

	return fsn_event;

}

static int create_fd(struct fsnotify_group *group,

	add_wait_queue(&group->notification_waitq, &wait);

	while (1) {

		spin_lock(&group->notification_lock);

		kevent = get_one_event(group, count);

		spin_unlock(&group->notification_lock);

		if (IS_ERR(kevent)) {

			ret = PTR_ERR(kevent);

			break;