Patch "iommu: Check dev->iommu in iommu_dev_xxx functions" has been added to the 5.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    iommu: Check dev->iommu in iommu_dev_xxx functions

to the 5.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     iommu-check-dev-iommu-in-iommu_dev_xxx-functions.patch
and it can be found in the queue-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit d9d21f7665ec656e00ecb9712373d5a9beff6645
Author: Shameer Kolothum <shameerali.kolothum.thodi@xxxxxxxxxx>
Date:   Wed Mar 3 17:36:11 2021 +0000

    iommu: Check dev->iommu in iommu_dev_xxx functions
    
    [ Upstream commit b9abb19fa5fd2d8a4be61c6cd4b2a48aa1a17f9c ]
    
    The device iommu probe/attach might have failed leaving dev->iommu
    to NULL and device drivers may still invoke these functions resulting
    in a crash in iommu vendor driver code.
    
    Hence make sure we check that.
    
    Fixes: a3a195929d40 ("iommu: Add APIs for multiple domains per device")
    Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@xxxxxxxxxx>
    Reviewed-by: Robin Murphy <robin.murphy@xxxxxxx>
    Link: https://lore.kernel.org/r/20210303173611.520-1-shameerali.kolothum.thodi@xxxxxxxxxx
    Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 0d9adce6d812..9b8664d388af 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -2872,10 +2872,12 @@ EXPORT_SYMBOL_GPL(iommu_dev_has_feature);
 
 int iommu_dev_enable_feature(struct device *dev, enum iommu_dev_features feat)
 {
-	const struct iommu_ops *ops = dev->bus->iommu_ops;
+	if (dev->iommu && dev->iommu->iommu_dev) {
+		const struct iommu_ops *ops = dev->iommu->iommu_dev->ops;
 
-	if (ops && ops->dev_enable_feat)
-		return ops->dev_enable_feat(dev, feat);
+		if (ops->dev_enable_feat)
+			return ops->dev_enable_feat(dev, feat);
+	}
 
 	return -ENODEV;
 }
@@ -2888,10 +2890,12 @@ EXPORT_SYMBOL_GPL(iommu_dev_enable_feature);
  */
 int iommu_dev_disable_feature(struct device *dev, enum iommu_dev_features feat)
 {
-	const struct iommu_ops *ops = dev->bus->iommu_ops;
+	if (dev->iommu && dev->iommu->iommu_dev) {
+		const struct iommu_ops *ops = dev->iommu->iommu_dev->ops;
 
-	if (ops && ops->dev_disable_feat)
-		return ops->dev_disable_feat(dev, feat);
+		if (ops->dev_disable_feat)
+			return ops->dev_disable_feat(dev, feat);
+	}
 
 	return -EBUSY;
 }
@@ -2899,10 +2903,12 @@ EXPORT_SYMBOL_GPL(iommu_dev_disable_feature);
 
 bool iommu_dev_feature_enabled(struct device *dev, enum iommu_dev_features feat)
 {
-	const struct iommu_ops *ops = dev->bus->iommu_ops;
+	if (dev->iommu && dev->iommu->iommu_dev) {
+		const struct iommu_ops *ops = dev->iommu->iommu_dev->ops;
 
-	if (ops && ops->dev_feat_enabled)
-		return ops->dev_feat_enabled(dev, feat);
+		if (ops->dev_feat_enabled)
+			return ops->dev_feat_enabled(dev, feat);
+	}
 
 	return false;
 }