[PATCH v2] arm: dma-mapping: Reset the device's dma_ops

[PATCH v2] arm: dma-mapping: Reset the device's dma_ops

[Sricharan R]

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-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
Fixes: 09515ef5ddad ("of/acpi: Configure dma operations at probe time for platform/amba/pci bus devices")
---
 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);
 }
 
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation

[PATCH v2] arm: dma-mapping: Reset the device's dma_ops

[Sricharan R]

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@codeaurora.org>
Fixes: 09515ef5ddad ("of/acpi: Configure dma operations at probe time for platform/amba/pci bus devices")
---
 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);
 }
 
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation

[PATCH v2] arm: dma-mapping: Reset the device's dma_ops

[Sricharan R]

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@codeaurora.org>
Fixes: 09515ef5ddad ("of/acpi: Configure dma operations at probe time for platform/amba/pci bus devices")
---
 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);
 }
 
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation

Re: [PATCH v2] arm: dma-mapping: Reset the device's dma_ops

[Laurent Pinchart]

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@codeaurora.org>
> 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)

> ---
>  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);
>  }

-- 
Regards,

Laurent Pinchart

[PATCH v2] arm: dma-mapping: Reset the device's dma_ops

[Laurent Pinchart]

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@codeaurora.org>
> 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)

> ---
>  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);
>  }

-- 
Regards,

Laurent Pinchart

Re: [PATCH v2] arm: dma-mapping: Reset the device's dma_ops

[Sricharan R]

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@codeaurora.org>
>> 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

> 
>> ---
>>  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);
>>  }
> 

-- 
"QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation

[PATCH v2] arm: dma-mapping: Reset the device's dma_ops

[Sricharan R]

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@codeaurora.org>
>> 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

> 
>> ---
>>  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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