Small semantical change of map_max_pages_need(): If given a 0 start

address, it is supposed to consider the worst case address range of the
given size.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26740 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/system/kernel/arch/x86/arch_vm_translation_map.cpp

@@ -328,6 +328,12 @@ put_page_table_entry_in_pgtable(page_table_entry *entry,
 static size_t
 map_max_pages_need(vm_translation_map */*map*/, addr_t start, addr_t end)
 {
+	// If start == 0, the actual base address is not yet known to the caller and
+	// we shall assume the worst case.
+	if (start == 0) {
+		start = 1023 * B_PAGE_SIZE;
+		end += 1023 * B_PAGE_SIZE;
+	}
 	return VADDR_TO_PDENT(end) + 1 - VADDR_TO_PDENT(start);
 }