[IA64] align high endpoint of VIRTUAL_MEM_MAP

Assure that vmem_map's high endpoint is MAX_ORDER aligned. Not doing so violates
the buddy allocator algorithm. Also anyone using mem=XXX on boot line and
not aligned to MAX_ORDER requires this patch in order to satisfy buddy
allocator. vmem_map always starts at pfn 0. The potentially large MAX_ORDER
on ia64 (due to hugetlbfs) requires that the end of vmem_map be aligned
to MAX_ORDER_NR_PAGES.

This was boot tested for: FLATMEM, FLATMEM+VIRTUAL_MEM_MAP,
DISCONTIGMEM+VIRTUAL_MEM_MAP and SPARSEMEM.

Signed-off-by: Bob Picco <bob.picco@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/arch/ia64/mm/discontig.c b/arch/ia64/mm/discontig.c
index 99bd9e30db96..8eeb669917fa 100644
--- a/arch/ia64/mm/discontig.c
+++ b/arch/ia64/mm/discontig.c
@@ -751,7 +751,8 @@ void __init paging_init(void)
         efi_memmap_walk(filter_rsvd_memory, count_node_pages);
 
 #ifdef CONFIG_VIRTUAL_MEM_MAP
-        vmalloc_end -= PAGE_ALIGN(max_low_pfn * sizeof(struct page));
+        vmalloc_end -= PAGE_ALIGN(ALIGN(max_low_pfn, MAX_ORDER_NR_PAGES) *
+                sizeof(struct page));
         vmem_map = (struct page *) vmalloc_end;
         efi_memmap_walk(create_mem_map_page_table, NULL);
         printk("Virtual mem_map starts at 0x%p\n", vmem_map);