memory hotplug: make alloc_bootmem_section()

alloc_bootmem_section() can allocate specified section's area.  This is used
for usemap to keep same section with pgdat by later patch.

Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 31 insertions, 0 deletions

diff --git a/mm/bootmem.c b/mm/bootmem.c
index 369624d2789c..e8fb927392b9 100644
--- a/mm/bootmem.c
+++ b/mm/bootmem.c
@@ -545,6 +545,37 @@ void * __init __alloc_bootmem_node(pg_data_t *pgdat, unsigned long size,
         return __alloc_bootmem(size, align, goal);
 }
 
+#ifdef CONFIG_SPARSEMEM
+void * __init alloc_bootmem_section(unsigned long size,
+                                    unsigned long section_nr)
+{
+        void *ptr;
+        unsigned long limit, goal, start_nr, end_nr, pfn;
+        struct pglist_data *pgdat;
+
+        pfn = section_nr_to_pfn(section_nr);
+        goal = PFN_PHYS(pfn);
+        limit = PFN_PHYS(section_nr_to_pfn(section_nr + 1)) - 1;
+        pgdat = NODE_DATA(early_pfn_to_nid(pfn));
+        ptr = __alloc_bootmem_core(pgdat->bdata, size, SMP_CACHE_BYTES, goal,
+                                   limit);
+
+        if (!ptr)
+                return NULL;
+
+        start_nr = pfn_to_section_nr(PFN_DOWN(__pa(ptr)));
+        end_nr = pfn_to_section_nr(PFN_DOWN(__pa(ptr) + size));
+        if (start_nr != section_nr || end_nr != section_nr) {
+                printk(KERN_WARNING "alloc_bootmem failed on section %ld.\n",
+                       section_nr);
+                free_bootmem_core(pgdat->bdata, __pa(ptr), size);
+                ptr = NULL;
+        }
+
+        return ptr;
+}
+#endif
+
 #ifndef ARCH_LOW_ADDRESS_LIMIT
 #define ARCH_LOW_ADDRESS_LIMIT  0xffffffffUL
 #endif