Is it illegal to drive a parking lot? (Better details below)

I frequent a restaurant and it's a one way road next to intersection; there's another road that would take me next to where I need to go. Is that illegal for me to cut through a parking lot of a restaurant to get to a road that intersects? I took this route due to me having to drive half a mile to get to a u-turn that'll take me back through. So I'm looking for clarification

Edit: I take the route to get on to a road to get back on to instead of going back through the one way all the way down until I reach another stop light that would allow for a I-turn