1 files changed, 59 insertions, 3 deletions

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index ed8b04867b1f..f7718d73e984 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -737,7 +737,7 @@ static int add_iommu_group(struct device *dev, void *data)
 	const struct iommu_ops *ops = cb->ops;
 
 	if (!ops->add_device)
-		return -ENODEV;
+		return 0;
 
 	WARN_ON(dev->iommu_group);
 
@@ -818,7 +818,15 @@ static int iommu_bus_init(struct bus_type *bus, const struct iommu_ops *ops)
 		kfree(nb);
 		return err;
 	}
-	return bus_for_each_dev(bus, NULL, &cb, add_iommu_group);
+
+	err = bus_for_each_dev(bus, NULL, &cb, add_iommu_group);
+	if (err) {
+		bus_unregister_notifier(bus, nb);
+		kfree(nb);
+		return err;
+	}
+
+	return 0;
 }
 
 /**
@@ -836,13 +844,19 @@ static int iommu_bus_init(struct bus_type *bus, const struct iommu_ops *ops)
  */
 int bus_set_iommu(struct bus_type *bus, const struct iommu_ops *ops)
 {
+	int err;
+
 	if (bus->iommu_ops != NULL)
 		return -EBUSY;
 
 	bus->iommu_ops = ops;
 
 	/* Do IOMMU specific setup for this bus-type */
-	return iommu_bus_init(bus, ops);
+	err = iommu_bus_init(bus, ops);
+	if (err)
+		bus->iommu_ops = NULL;
+
+	return err;
 }
 EXPORT_SYMBOL_GPL(bus_set_iommu);
 
@@ -1124,6 +1138,48 @@ size_t iommu_unmap(struct iommu_domain *domain, unsigned long iova, size_t size)
 }
 EXPORT_SYMBOL_GPL(iommu_unmap);
 
+size_t default_iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
+			 struct scatterlist *sg, unsigned int nents, int prot)
+{
+	struct scatterlist *s;
+	size_t mapped = 0;
+	unsigned int i, min_pagesz;
+	int ret;
+
+	if (unlikely(domain->ops->pgsize_bitmap == 0UL))
+		return 0;
+
+	min_pagesz = 1 << __ffs(domain->ops->pgsize_bitmap);
+
+	for_each_sg(sg, s, nents, i) {
+		phys_addr_t phys = page_to_phys(sg_page(s)) + s->offset;
+
+		/*
+		 * We are mapping on IOMMU page boundaries, so offset within
+		 * the page must be 0. However, the IOMMU may support pages
+		 * smaller than PAGE_SIZE, so s->offset may still represent
+		 * an offset of that boundary within the CPU page.
+		 */
+		if (!IS_ALIGNED(s->offset, min_pagesz))
+			goto out_err;
+
+		ret = iommu_map(domain, iova + mapped, phys, s->length, prot);
+		if (ret)
+			goto out_err;
+
+		mapped += s->length;
+	}
+
+	return mapped;
+
+out_err:
+	/* undo mappings already done */
+	iommu_unmap(domain, iova, mapped);
+
+	return 0;
+
+}
+EXPORT_SYMBOL_GPL(default_iommu_map_sg);
 
 int iommu_domain_window_enable(struct iommu_domain *domain, u32 wnd_nr,
 			       phys_addr_t paddr, u64 size, int prot)