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authorGerald Schaefer <gerald.schaefer@de.ibm.com>2012-02-24 18:01:29 +0100
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2012-02-24 18:01:36 +0100
commit892365ab4d29ed861709ee8611b53587ca2bb75f (patch)
treee66d38b909ee69025d996a37cb27e2f1ad8c4210 /arch/s390/mm
parentd60331ac0d961ae063e69c43f09d14244ad5d921 (diff)
downloadlinux-linaro-stable-892365ab4d29ed861709ee8611b53587ca2bb75f.tar.gz
[S390] memory hotplug: prevent memory zone interleave
This fixes a kernel oops with CONFIG_DEBUG_VM triggered by a VM_BUG_ON(bad_range()): kernel BUG at mm/page_alloc.c:748. With memory hotplug on System z, it is possible that the memory online/offline state is preserved over a system restart, e.g. there may be offline memory blocks in ZONE_DMA or ZONE_NORMAL. So far, the offline memory range has always been added to ZONE_MOVABLE during system start, so that it was possible to have ZONE_MOVABLE interleave with ZONE_DMA or ZONE_NORMAL. This patch fixes that by checking for zone overlap before adding memory. Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/mm')
-rw-r--r--arch/s390/mm/init.c30
1 files changed, 26 insertions, 4 deletions
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index 5d633019d8f3..50236610de83 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -223,16 +223,38 @@ void free_initrd_mem(unsigned long start, unsigned long end)
#ifdef CONFIG_MEMORY_HOTPLUG
int arch_add_memory(int nid, u64 start, u64 size)
{
- struct pglist_data *pgdat;
+ unsigned long zone_start_pfn, zone_end_pfn, nr_pages;
+ unsigned long start_pfn = PFN_DOWN(start);
+ unsigned long size_pages = PFN_DOWN(size);
struct zone *zone;
int rc;
- pgdat = NODE_DATA(nid);
- zone = pgdat->node_zones + ZONE_MOVABLE;
rc = vmem_add_mapping(start, size);
if (rc)
return rc;
- rc = __add_pages(nid, zone, PFN_DOWN(start), PFN_DOWN(size));
+ for_each_zone(zone) {
+ if (zone_idx(zone) != ZONE_MOVABLE) {
+ /* Add range within existing zone limits */
+ zone_start_pfn = zone->zone_start_pfn;
+ zone_end_pfn = zone->zone_start_pfn +
+ zone->spanned_pages;
+ } else {
+ /* Add remaining range to ZONE_MOVABLE */
+ zone_start_pfn = start_pfn;
+ zone_end_pfn = start_pfn + size_pages;
+ }
+ if (start_pfn < zone_start_pfn || start_pfn >= zone_end_pfn)
+ continue;
+ nr_pages = (start_pfn + size_pages > zone_end_pfn) ?
+ zone_end_pfn - start_pfn : size_pages;
+ rc = __add_pages(nid, zone, start_pfn, nr_pages);
+ if (rc)
+ break;
+ start_pfn += nr_pages;
+ size_pages -= nr_pages;
+ if (!size_pages)
+ break;
+ }
if (rc)
vmem_remove_mapping(start, size);
return rc;