diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 435ce0387186..67c3d70ed946 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -2073,10 +2073,13 @@ static int arm_smmu_map(struct iommu_domain *domain, unsigned long iova,
 	return ret;
 }
 
+static size_t arm_smmu_unmap(struct iommu_domain *domain, unsigned long iova,
+			     size_t size);
 static size_t arm_smmu_map_sg(struct iommu_domain *domain, unsigned long iova,
 			   struct scatterlist *sg, unsigned int nents, int prot)
 {
 	int ret;
+	size_t size;
 	unsigned long flags;
 	struct arm_smmu_domain *smmu_domain = domain->priv;
 	struct io_pgtable_ops *ops = smmu_domain->pgtbl_ops;
@@ -2085,12 +2088,15 @@ static size_t arm_smmu_map_sg(struct iommu_domain *domain, unsigned long iova,
 		return -ENODEV;
 
 	spin_lock_irqsave(&smmu_domain->pgtbl_lock, flags);
-	ret = ops->map_sg(ops, iova, sg, nents, prot);
+	ret = ops->map_sg(ops, iova, sg, nents, prot, &size);
 	spin_unlock_irqrestore(&smmu_domain->pgtbl_lock, flags);
 
-	if (ret)
+	if (ret) {
 		if (arm_smmu_assign_table(smmu_domain))
 			return 0;
+	} else {
+		arm_smmu_unmap(domain, iova, size);
+	}
 
 	return ret;
 }
diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 83cd01d80617..6274edc5e1ec 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -459,7 +459,7 @@ static int arm_lpae_map(struct io_pgtable_ops *ops, unsigned long iova,
 
 static int arm_lpae_map_sg(struct io_pgtable_ops *ops, unsigned long iova,
 			   struct scatterlist *sg, unsigned int nents,
-			   int iommu_prot)
+			   int iommu_prot, size_t *size)
 {
 	struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
 	arm_lpae_iopte *ptep = data->pgd;
@@ -469,7 +469,6 @@ static int arm_lpae_map_sg(struct io_pgtable_ops *ops, unsigned long iova,
 	size_t mapped = 0;
 	int i, ret;
 	unsigned int min_pagesz;
-	unsigned long orig_iova = iova;
 	struct map_state ms;
 
 	/* If no access, then nothing to do */
@@ -529,10 +528,8 @@ static int arm_lpae_map_sg(struct io_pgtable_ops *ops, unsigned long iova,
 	return mapped;
 
 out_err:
-	/* undo mappings already done */
-	if (mapped)
-		ops->unmap(ops, orig_iova, mapped);
-
+	/* Return the size of the partial mapping so that they can be undone */
+	*size = mapped;
 	return 0;
 }
 
diff --git a/drivers/iommu/io-pgtable.h b/drivers/iommu/io-pgtable.h
index c1c656bd7a8e..f74f148ea76f 100644
--- a/drivers/iommu/io-pgtable.h
+++ b/drivers/iommu/io-pgtable.h
@@ -77,6 +77,8 @@ struct io_pgtable_cfg {
  * struct io_pgtable_ops - Page table manipulation API for IOMMU drivers.
  *
  * @map:          Map a physically contiguous memory region.
+ * @map_sg:	  Map a scatterlist. The size parameter contains the size
+ *		  of the partial mapping in case of failure.
  * @unmap:        Unmap a physically contiguous memory region.
  * @iova_to_phys: Translate iova to physical address.
  *
@@ -87,7 +89,8 @@ struct io_pgtable_ops {
 	int (*map)(struct io_pgtable_ops *ops, unsigned long iova,
 		   phys_addr_t paddr, size_t size, int prot);
 	int (*map_sg)(struct io_pgtable_ops *ops, unsigned long iova,
-			 struct scatterlist *sg, unsigned int nents, int prot);
+			 struct scatterlist *sg, unsigned int nents,
+			 int prot, size_t *size);
 	size_t (*unmap)(struct io_pgtable_ops *ops, unsigned long iova,
 			size_t size);
 	phys_addr_t (*iova_to_phys)(struct io_pgtable_ops *ops,