[PATCH] Fix sparsemem on Cell

Fix an oops experienced on the Cell architecture when init-time functions,
early_*(), are called at runtime.  It alters the call paths to make sure
that the callers explicitly say whether the call is being made on behalf of
a hotplug even, or happening at boot-time.

It has been compile tested on ppc64, ia64, s390, i386 and x86_64.

Acked-by: Arnd Bergmann <arndb@de.ibm.com>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Acked-by: Andy Whitcroft <apw@shadowen.org>
Cc: Christoph Lameter <clameter@engr.sgi.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 21 insertions, 10 deletions

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 0c055a090f4d..84279127fcd3 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -67,11 +67,13 @@ static int __add_zone(struct zone *zone, unsigned long phys_start_pfn)
         zone_type = zone - pgdat->node_zones;
         if (!populated_zone(zone)) {
                 int ret = 0;
-                ret = init_currently_empty_zone(zone, phys_start_pfn, nr_pages);
+                ret = init_currently_empty_zone(zone, phys_start_pfn,
+                                                nr_pages, MEMMAP_HOTPLUG);
                 if (ret < 0)
                         return ret;
         }
-        memmap_init_zone(nr_pages, nid, zone_type, phys_start_pfn);
+        memmap_init_zone(nr_pages, nid, zone_type,
+                         phys_start_pfn, MEMMAP_HOTPLUG);
         return 0;
 }
 
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index a49f96b7ea43..fc5b5442e942 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1956,17 +1956,24 @@ static inline unsigned long wait_table_bits(unsigned long size)
  * done. Non-atomic initialization, single-pass.
  */
 void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
-                unsigned long start_pfn)
+                unsigned long start_pfn, enum memmap_context context)
 {
         struct page *page;
         unsigned long end_pfn = start_pfn + size;
         unsigned long pfn;
 
         for (pfn = start_pfn; pfn < end_pfn; pfn++) {
-                if (!early_pfn_valid(pfn))
-                        continue;
-                if (!early_pfn_in_nid(pfn, nid))
-                        continue;
+                /*
+                 * There can be holes in boot-time mem_map[]s
+                 * handed to this function.  They do not
+                 * exist on hotplugged memory.
+                 */
+                if (context == MEMMAP_EARLY) {
+                        if (!early_pfn_valid(pfn))
+                                continue;
+                        if (!early_pfn_in_nid(pfn, nid))
+                                continue;
+                }
                 page = pfn_to_page(pfn);
                 set_page_links(page, zone, nid, pfn);
                 init_page_count(page);
@@ -1993,7 +2000,7 @@ void zone_init_free_lists(struct pglist_data *pgdat, struct zone *zone,
 
 #ifndef __HAVE_ARCH_MEMMAP_INIT
 #define memmap_init(size, nid, zone, start_pfn) \
-        memmap_init_zone((size), (nid), (zone), (start_pfn))
+        memmap_init_zone((size), (nid), (zone), (start_pfn), MEMMAP_EARLY)
 #endif
 
 static int __cpuinit zone_batchsize(struct zone *zone)
@@ -2239,7 +2246,8 @@ static __meminit void zone_pcp_init(struct zone *zone)
 
 __meminit int init_currently_empty_zone(struct zone *zone,
                                         unsigned long zone_start_pfn,
-                                        unsigned long size)
+                                        unsigned long size,
+                                        enum memmap_context context)
 {
         struct pglist_data *pgdat = zone->zone_pgdat;
         int ret;
@@ -2683,7 +2691,8 @@ static void __meminit free_area_init_core(struct pglist_data *pgdat,
                 if (!size)
                         continue;
 
-                ret = init_currently_empty_zone(zone, zone_start_pfn, size);
+                ret = init_currently_empty_zone(zone, zone_start_pfn,
+                                                size, MEMMAP_EARLY);
                 BUG_ON(ret);
                 zone_start_pfn += size;
         }