I was looking through the buffer manager's code and have noticed that function PinBuffer has an unused 'strategy' argument. It's seems that after refactoring made by Alexander Korotkov and Andres Freund (48354581a49c30f5757c203415aa8412d85b0f70) it became useless. The attached patch removes it. Probably someone more advanced could edit the function description to reflect changes?
48354581 contain unintentional change that made 'strategy' argument of PinBuffer unused.
Since it was an unintentional change, it was decided to put old logic back. See 9cf60332.
Thus, now 'strategy' argument of PinBuffer is used.