1) SLR backpack
2) Laptop
3) Cabin Luggage

Three items is way over a carry on and a "personal item". Depending on the laptop bag that may qualify as a personal item, but either the backpack or cabin luggage will have to go.

Granted most times they won't even look at you and you can bring it all on board, but they can require you to check or gate check one of the bags.

I would try to combine them down to one bag and a personal item if you can.