I'd dig it up, separate the garlic and replant (I assume it's growing in a clump at this point). If you let them grow as they are then the bulbs will be quite small next year. Garlic needs to be dug and replanted every year for the biggest bulbs.

When 1/2 to 2/3 of the leaves turn brown in summer, you harvest the bulbs and cure them for eating and replanting.

Rodney

I have left garlic in the ground for 2 winters. They produce many bulbs, one bulb from each clove in the old bulb formed from that one original clove. So I say just leave them till next summer and harvest then. Why bother now.

If you leave them in the ground , unharvested for years, the will keep dividing and growing like chives. Sure, you can use the green just like garlic chives.