int order;
while (start < end) {
- order = min(MAX_ORDER - 1UL, __ffs(start));
+ /*
+ * Free the pages in the largest chunks alignment allows.
+ *
+ * __ffs() behaviour is undefined for 0. start == 0 is
+ * MAX_ORDER-aligned, set order to MAX_ORDER for the case.
+ */
+ if (start)
+ order = min_t(int, MAX_ORDER, __ffs(start));
+ else
+ order = MAX_ORDER;
while (start + (1UL << order) > end)
order--;