diff --git a/arch/s390/pci/pci_dma.c b/arch/s390/pci/pci_dma.c
index ebc9a49523aa3182e0949c5e442ed24016427b6d..f6690a7003c6e274018343c9864786a5d09de0f3 100644
--- a/arch/s390/pci/pci_dma.c
+++ b/arch/s390/pci/pci_dma.c
@@ -541,6 +541,17 @@ static void s390_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
 		s->dma_length = 0;
 	}
 }
+
+static unsigned long *bitmap_vzalloc(size_t bits, gfp_t flags)
+{
+	size_t n = BITS_TO_LONGS(bits);
+	size_t bytes;
+
+	if (unlikely(check_mul_overflow(n, sizeof(unsigned long), &bytes)))
+		return NULL;
+
+	return vzalloc(bytes);
+}
 	
 int zpci_dma_init_device(struct zpci_dev *zdev)
 {
@@ -577,13 +588,13 @@ int zpci_dma_init_device(struct zpci_dev *zdev)
 				zdev->end_dma - zdev->start_dma + 1);
 	zdev->end_dma = zdev->start_dma + zdev->iommu_size - 1;
 	zdev->iommu_pages = zdev->iommu_size >> PAGE_SHIFT;
-	zdev->iommu_bitmap = vzalloc(zdev->iommu_pages / 8);
+	zdev->iommu_bitmap = bitmap_vzalloc(zdev->iommu_pages, GFP_KERNEL);
 	if (!zdev->iommu_bitmap) {
 		rc = -ENOMEM;
 		goto free_dma_table;
 	}
 	if (!s390_iommu_strict) {
-		zdev->lazy_bitmap = vzalloc(zdev->iommu_pages / 8);
+		zdev->lazy_bitmap = bitmap_vzalloc(zdev->iommu_pages, GFP_KERNEL);
 		if (!zdev->lazy_bitmap) {
 			rc = -ENOMEM;
 			goto free_bitmap;