iommu/amd: Handle integer overflow in dma_ops_area_alloc

commit e6aabee0 upstream.

Handle this case to make sure boundary_size does not become
0 and trigger a BUG_ON later.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

drivers/iommu/amd_iommu.c

@@ -1750,14 +1750,16 @@ static unsigned long dma_ops_area_alloc(struct device *dev,
 	unsigned long next_bit = dom->next_address % APERTURE_RANGE_SIZE;
 	int max_index = dom->aperture_size >> APERTURE_RANGE_SHIFT;
 	int i = start >> APERTURE_RANGE_SHIFT;
-	unsigned long boundary_size;
+	unsigned long boundary_size, mask;
 	unsigned long address = -1;
 	unsigned long limit;
 
 	next_bit >>= PAGE_SHIFT;
 
-	boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
-			PAGE_SIZE) >> PAGE_SHIFT;
+	mask = dma_get_seg_boundary(dev);
+
+	boundary_size = mask + 1 ? ALIGN(mask + 1, PAGE_SIZE) >> PAGE_SHIFT :
+				   1UL << (BITS_PER_LONG - PAGE_SHIFT);
 
 	for (;i < max_index; ++i) {
 		unsigned long offset = dom->aperture[i]->offset >> PAGE_SHIFT;