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:
>> 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 <sricharan@xxxxxxxxxxxxxx>
>> Fixes: 09515ef5ddad ("of/acpi: Configure dma operations at probe time for
>> platform/amba/pci bus devices")
>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
>
> 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
>
>> ---
>> 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));
>> }
>> -
>> -/**
>> - * 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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