+static inline struct mem_section *__nr_to_section(unsigned long nr)
+{
+ return &mem_section[nr];
+}
+
+/*
+ * We use the lower bits of the mem_map pointer to store
+ * a little bit of information. There should be at least
+ * 3 bits here due to 32-bit alignment.
+ */
+#define SECTION_MARKED_PRESENT (1UL<<0)
+#define SECTION_HAS_MEM_MAP (1UL<<1)
+#define SECTION_MAP_LAST_BIT (1UL<<2)
+#define SECTION_MAP_MASK (~(SECTION_MAP_LAST_BIT-1))
+
+static inline struct page *__section_mem_map_addr(struct mem_section *section)
+{
+ unsigned long map = section->section_mem_map;
+ map &= SECTION_MAP_MASK;
+ return (struct page *)map;
+}
+
+static inline int valid_section(struct mem_section *section)
+{
+ return (section->section_mem_map & SECTION_MARKED_PRESENT);
+}
+
+static inline int section_has_mem_map(struct mem_section *section)
+{
+ return (section->section_mem_map & SECTION_HAS_MEM_MAP);
+}
+
+static inline int valid_section_nr(unsigned long nr)
+{
+ return valid_section(__nr_to_section(nr));
+}
+