1 files changed, 44 insertions, 1 deletions

diff --git a/mm/sparse.c b/mm/sparse.c
index 5032c9a619de..9d7fd666015e 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -222,7 +222,8 @@ void __init memory_present(int nid, unsigned long start, unsigned long end)
 
                 ms = __nr_to_section(section);
                 if (!ms->section_mem_map) {
-                        ms->section_mem_map = sparse_encode_early_nid(nid);
+                        ms->section_mem_map = sparse_encode_early_nid(nid) |
+                                                        SECTION_IS_ONLINE;
                         section_mark_present(ms);
                 }
         }
@@ -622,6 +623,48 @@ void __init sparse_init(void)
 }
 
 #ifdef CONFIG_MEMORY_HOTPLUG
+
+/* Mark all memory sections within the pfn range as online */
+void online_mem_sections(unsigned long start_pfn, unsigned long end_pfn)
+{
+        unsigned long pfn;
+
+        for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
+                unsigned long section_nr = pfn_to_section_nr(start_pfn);
+                struct mem_section *ms;
+
+                /* onlining code should never touch invalid ranges */
+                if (WARN_ON(!valid_section_nr(section_nr)))
+                        continue;
+
+                ms = __nr_to_section(section_nr);
+                ms->section_mem_map |= SECTION_IS_ONLINE;
+        }
+}
+
+#ifdef CONFIG_MEMORY_HOTREMOVE
+/* Mark all memory sections within the pfn range as online */
+void offline_mem_sections(unsigned long start_pfn, unsigned long end_pfn)
+{
+        unsigned long pfn;
+
+        for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
+                unsigned long section_nr = pfn_to_section_nr(start_pfn);
+                struct mem_section *ms;
+
+                /*
+                 * TODO this needs some double checking. Offlining code makes
+                 * sure to check pfn_valid but those checks might be just bogus
+                 */
+                if (WARN_ON(!valid_section_nr(section_nr)))
+                        continue;
+
+                ms = __nr_to_section(section_nr);
+                ms->section_mem_map &= ~SECTION_IS_ONLINE;
+        }
+}
+#endif
+
 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid)
 {