Hi Laurent,

On 5/26/2017 7:44 PM, Laurent Pinchart wrote:

Hi Sricharan,

Thank you for the patch.

On Friday 26 May 2017 16:13:37 Sricharan R wrote:

quoted

arch_teardown_dma_ops() being the inverse of arch_setup_dma_ops()
,dma_ops should be cleared in the teardown path. Currently, only the
device's iommu mapping structures are cleared in arch_teardown_dma_ops,
but not the dma_ops. So on the next reprobe, dma_ops left in place is
stale from the first IOMMU setup, but iommu mappings has been disposed
of. This is a problem when the probe of the device is deferred and
recalled with the IOMMU probe deferral.

So for fixing this, slightly refactor by moving the code from
__arm_iommu_detach_device to arm_iommu_detach_device and cleanup
the former. This takes care of resetting the dma_ops in the teardown
path.

Signed-off-by: Sricharan R <redacted>
Fixes: 09515ef5ddad ("of/acpi: Configure dma operations at probe time for
platform/amba/pci bus devices")

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

Could you please push this upstream along with "[PATCH] ARM: dma-mapping: 
Don't tear third-party mappings" ?

(And feel free to s/tear/tear down/ in the subject of that patch, I've only 
noticed now that I forgot one word)

ok, will change the above and post it with the other patches.

Regards,
 Sricharan

quoted

---
 arch/arm/mm/dma-mapping.c | 25 ++++++++++---------------
 1 file changed, 10 insertions(+), 15 deletions(-)

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index c742dfd..6e82e87 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c

@@ -2311,7 +2311,14 @@ int arm_iommu_attach_device(struct device *dev,
 }
 EXPORT_SYMBOL_GPL(arm_iommu_attach_device);

-static void __arm_iommu_detach_device(struct device *dev)
+/**
+ * arm_iommu_detach_device
+ * @dev: valid struct device pointer
+ *
+ * Detaches the provided device from a previously attached map.
+ * This voids the dma operations (dma_map_ops pointer)
+ */
+void arm_iommu_detach_device(struct device *dev)
 {
 	struct dma_iommu_mapping *mapping;

@@ -2324,22 +2331,10 @@ static void __arm_iommu_detach_device(struct device

*dev) iommu_detach_device(mapping->domain, dev);
 	kref_put(&mapping->kref, release_iommu_mapping);
 	to_dma_iommu_mapping(dev) = NULL;
+	set_dma_ops(dev, NULL);

 	pr_debug("Detached IOMMU controller from %s device.\n", 

dev_name(dev));

quoted

 }
-
-/**
- * arm_iommu_detach_device
- * @dev: valid struct device pointer
- *
- * Detaches the provided device from a previously attached map.
- * This voids the dma operations (dma_map_ops pointer)
- */
-void arm_iommu_detach_device(struct device *dev)
-{
-	__arm_iommu_detach_device(dev);
-	set_dma_ops(dev, NULL);
-}
 EXPORT_SYMBOL_GPL(arm_iommu_detach_device);

 static const struct dma_map_ops *arm_get_iommu_dma_map_ops(bool coherent)

@@ -2379,7 +2374,7 @@ static void arm_teardown_iommu_dma_ops(struct device

*dev) if (!mapping)
 		return;

-	__arm_iommu_detach_device(dev);
+	arm_iommu_detach_device(dev);
 	arm_iommu_release_mapping(mapping);
 }

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