[PATCH] vmalloc.c: fix lose num_physpages checking

["Figo.zhang" <figo1802@gmail.com>]

__get_vm_area_node() lose size (physpages limit) checking, it be called by
__get_vm_area() that some drivers called it directly.

Signed-off-by: Figo.zhang  <figo1802@gmail.com>
--- 
mm/vmalloc.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index f8189a4..99f3aea 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1144,7 +1144,7 @@ static struct vm_struct *__get_vm_area_node(unsigned long size,
 	}
 
 	size = PAGE_ALIGN(size);
-	if (unlikely(!size))
+	if (unlikely(!size || (size >> PAGE_SHIFT) > num_physpages))
 		return NULL;
 
 	area = kmalloc_node(sizeof(*area), gfp_mask & GFP_RECLAIM_MASK, node);