diff --git a/lib/iommu-helper.c b/lib/iommu-helper.c
index 75dbda0..c0251f4 100644
--- a/lib/iommu-helper.c
+++ b/lib/iommu-helper.c
@@ -3,41 +3,7 @@
  */
 
 #include <linux/module.h>
-#include <linux/bitops.h>
-
-static unsigned long find_next_zero_area(unsigned long *map,
-					 unsigned long size,
-					 unsigned long start,
-					 unsigned int nr,
-					 unsigned long align_mask)
-{
-	unsigned long index, end, i;
-again:
-	index = find_next_zero_bit(map, size, start);
-
-	/* Align allocation */
-	index = (index + align_mask) & ~align_mask;
-
-	end = index + nr;
-	if (end >= size)
-		return -1;
-	for (i = index; i < end; i++) {
-		if (test_bit(i, map)) {
-			start = i+1;
-			goto again;
-		}
-	}
-	return index;
-}
-
-void iommu_area_reserve(unsigned long *map, unsigned long i, int len)
-{
-	unsigned long end = i + len;
-	while (i < end) {
-		__set_bit(i, map);
-		i++;
-	}
-}
+#include <linux/bitmap.h>
 
 int iommu_is_span_boundary(unsigned int index, unsigned int nr,
 			   unsigned long shift,
@@ -55,31 +21,24 @@
 			       unsigned long align_mask)
 {
 	unsigned long index;
+
+	/* We don't want the last of the limit */
+	size -= 1;
 again:
-	index = find_next_zero_area(map, size, start, nr, align_mask);
-	if (index != -1) {
+	index = bitmap_find_next_zero_area(map, size, start, nr, align_mask);
+	if (index < size) {
 		if (iommu_is_span_boundary(index, nr, shift, boundary_size)) {
 			/* we could do more effectively */
 			start = index + 1;
 			goto again;
 		}
-		iommu_area_reserve(map, index, nr);
+		bitmap_set(map, index, nr);
+		return index;
 	}
-	return index;
+	return -1;
 }
 EXPORT_SYMBOL(iommu_area_alloc);
 
-void iommu_area_free(unsigned long *map, unsigned long start, unsigned int nr)
-{
-	unsigned long end = start + nr;
-
-	while (start < end) {
-		__clear_bit(start, map);
-		start++;
-	}
-}
-EXPORT_SYMBOL(iommu_area_free);
-
 unsigned long iommu_num_pages(unsigned long addr, unsigned long len,
 			      unsigned long io_page_size)
 {