Add vmalloc alignment constraints

vmalloc is used by ioremap() to get regions for
remapping I/O space.  To feed these regions back
into a __get_free_pages() type memory allocator,
they are expected to have more alignment than 
get_vm_area() proves.  So add additional alignment
constraints for VM_IOREMAP.
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

mm/vmalloc.c

@@ -179,11 +179,27 @@ int map_vm_area(struct vm_struct *area, pgprot_t prot, struct page ***pages)
 	return err;
 }
 
+#define IOREMAP_MAX_ORDER	(3 + PAGE_SHIFT)	/* 8 pages */
+
 struct vm_struct *__get_vm_area(unsigned long size, unsigned long flags,
 				unsigned long start, unsigned long end)
 {
 	struct vm_struct **p, *tmp, *area;
-	unsigned long addr = start;
+	unsigned long align = 1;
+	unsigned long addr;
+
+	if (flags & VM_IOREMAP) {
+		int bit = fls(size);
+
+		if (bit > IOREMAP_MAX_ORDER)
+			bit = IOREMAP_MAX_ORDER;
+		else if (bit < PAGE_SHIFT)
+			bit = PAGE_SHIFT;
+
+		align = 1ul << bit;
+	}
+	addr = ALIGN(start, align);
+
 
 	area = kmalloc(sizeof(*area), GFP_KERNEL);
 	if (unlikely(!area))
@@ -206,7 +222,7 @@ struct vm_struct *__get_vm_area(unsigned long size, unsigned long flags,
 			goto out;
 		if (size + addr <= (unsigned long)tmp->addr)
 			goto found;
-		addr = tmp->size + (unsigned long)tmp->addr;
+		addr = ALIGN(tmp->size + (unsigned long)tmp->addr, align);
 		if (addr > end - size)
 			goto out;
 	}