diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 54d96e847f16..381b60d9e7ce 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -1918,12 +1918,18 @@ static int iommu_dma_iova_link_swiotlb(struct device *dev,
 			return 0;
 	}
 
+	/*
+	 * After removing the partial head and tail, there may be no aligned
+	 * middle left to map.  The tail still gets bounced below.
+	 */
 	size -= iova_end_pad;
-	error = __dma_iova_link(dev, addr + mapped, phys + mapped, size, dir,
-			attrs);
-	if (error)
-		goto out_unmap;
-	mapped += size;
+	if (size) {
+		error = __dma_iova_link(dev, addr + mapped, phys + mapped,
+				size, dir, attrs);
+		if (error)
+			goto out_unmap;
+		mapped += size;
+	}
 
 	if (iova_end_pad) {
 		error = iommu_dma_iova_bounce_and_link(dev, addr + mapped,
@@ -1936,7 +1942,8 @@ static int iommu_dma_iova_link_swiotlb(struct device *dev,
 	return 0;
 
 out_unmap:
-	dma_iova_unlink(dev, state, 0, mapped, dir, attrs);
+	if (mapped)
+		dma_iova_unlink(dev, state, offset, mapped, dir, attrs);
 	return error;
 }
 
diff --git a/kernel/dma/debug.c b/kernel/dma/debug.c
index 3248f8b4d096..2c0e2cd89b5e 100644
--- a/kernel/dma/debug.c
+++ b/kernel/dma/debug.c
@@ -1556,7 +1556,7 @@ void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
 		struct dma_debug_entry ref = {
 			.type           = dma_debug_sg,
 			.dev            = dev,
-			.paddr		= sg_phys(sg),
+			.paddr		= sg_phys(s),
 			.dev_addr       = sg_dma_address(s),
 			.size           = sg_dma_len(s),
 			.direction      = direction,
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 583c5922bca2..4391b797d4db 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -476,7 +476,7 @@ int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
 			 * must be mapped with CPU physical address and not PCI
 			 * bus addresses.
 			 */
-			break;
+			fallthrough;
 		case PCI_P2PDMA_MAP_NONE:
 			need_sync = true;
 			sg->dma_address = dma_direct_map_phys(dev, sg_phys(sg),