iommu: Revert pasid attachment only for the devices that have succeeded

There is no error hanlding now in __iommu_set_group_pasid(), it relies on
the caller to loop all the devices to revert pasid attachment if the
__iommu_set_group_pasid() failed. This is not perfect for the multi-device
groups. It's better to handle the error within __iommu_set_group_pasid(),
and only revert the devices that have succeeded.

Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>

drivers/iommu/iommu.c

@@ -3306,15 +3306,25 @@ EXPORT_SYMBOL_GPL(iommu_group_dma_owner_claimed);
 static int __iommu_set_group_pasid(struct iommu_domain *domain,
 				   struct iommu_group *group, ioasid_t pasid)
 {
-	struct group_device *device;
-	int ret = 0;
+	struct group_device *device, *last_gdev;
+	int ret;
 
 	for_each_group_device(group, device) {
 		ret = domain->ops->set_dev_pasid(domain, device->dev, pasid);
 		if (ret)
-			break;
+			goto err_revert;
 	}
 
+	return 0;
+
+err_revert:
+	last_gdev = device;
+	for_each_group_device(group, device) {
+		if (device == last_gdev)
+			break;
+		dev_iommu_ops(device->dev)->remove_dev_pasid(device->dev,
+							     pasid);
+	}
 	return ret;
 }
 
@@ -3363,10 +3373,8 @@ int iommu_attach_device_pasid(struct iommu_domain *domain,
 	}
 
 	ret = __iommu_set_group_pasid(domain, group, pasid);
-	if (ret) {
-		__iommu_remove_group_pasid(group, pasid);
+	if (ret)
 		xa_erase(&group->pasid_array, pasid);
-	}
 out_unlock:
 	mutex_unlock(&group->mutex);
 	return ret;