maximum mis-classification loss of hinge loss

In the plots and in some lecture notes, I read that hinge loss is bounded between (0,2). But I can not understand that. By definition, hinge loss is (standard one)

max(0,1-yf(x))

In case of false positive, this value becomes,

max(0,1+f(x))

Clearly, f(x) can be greater than 1. It's value depends on how far the example lies from the marginal hyper-plane corresponds to w'x+b=−1. Can anyone explain why upper bound is 2 ?.