Merge tag 'iommu-fixes-v4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu

Pul IOMMU fixes from Joerg Roedel:
 "Four fixes have queued up to fix regressions introduced after v4.1:

   - Don't fail IOMMU driver initialization when the add_device
     call-back returns -ENODEV, as that just means that the device is
     not translated by the IOMMU.  This is pretty common on ARM.

   - Two fixes for the ARM-SMMU driver for a wrong feature check and to
     remove a redundant NULL check.

   - A fix for the AMD IOMMU driver to fix a boot panic on systems where
     the BIOS requests Unity Mappings in the IVRS table"

* tag 'iommu-fixes-v4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
  iommu/amd: Introduce protection_domain_init() function
  iommu/arm-smmu: Delete an unnecessary check before the function call "free_io_pgtable_ops"
  iommu/arm-smmu: Fix broken ATOS check
  iommu: Ignore -ENODEV errors from add_device call-back

1 files changed, 12 insertions, 1 deletions

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 49e7542510d1..f286090931cc 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -847,13 +847,24 @@ static int add_iommu_group(struct device *dev, void *data)
 {
 	struct iommu_callback_data *cb = data;
 	const struct iommu_ops *ops = cb->ops;
+	int ret;
 
 	if (!ops->add_device)
 		return 0;
 
 	WARN_ON(dev->iommu_group);
 
-	return ops->add_device(dev);
+	ret = ops->add_device(dev);
+
+	/*
+	 * We ignore -ENODEV errors for now, as they just mean that the
+	 * device is not translated by an IOMMU. We still care about
+	 * other errors and fail to initialize when they happen.
+	 */
+	if (ret == -ENODEV)
+		ret = 0;
+
+	return ret;
 }
 
 static int remove_iommu_group(struct device *dev, void *data)