fsnotify: Pass fsnotify_iter_info into handle_event handler

Pass fsnotify_iter_info into ->handle_event() handler so that it can
release and reacquire SRCU lock via fsnotify_prepare_user_wait() and
fsnotify_finish_user_wait() functions.  These functions also make sure
current marks are appropriately pinned so that iteration protected by
srcu in fsnotify() stays safe.

Reviewed-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>

fs/notify/dnotify/dnotify.c

@@ -85,7 +85,8 @@ static int dnotify_handle_event(struct fsnotify_group *group,
 				struct fsnotify_mark *inode_mark,
 				struct fsnotify_mark *vfsmount_mark,
 				u32 mask, const void *data, int data_type,
-				const unsigned char *file_name, u32 cookie)
+				const unsigned char *file_name, u32 cookie,
+				struct fsnotify_iter_info *iter_info)
 {
 	struct dnotify_mark *dn_mark;
 	struct dnotify_struct *dn;