[PATCH 1/1] iommu: Remove iommu_present()

[PATCH 1/1] iommu: Remove iommu_present()

[Lu Baolu]

The last callsite of iommu_present() is removed by commit <45c690aea8ee>
("drm/tegra: Use iommu_paging_domain_alloc()"). Remove it to avoid dead
code.

Fixes: 45c690aea8ee ("drm/tegra: Use iommu_paging_domain_alloc()")
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
---
 include/linux/iommu.h |  6 ------
 drivers/iommu/iommu.c | 25 -------------------------
 2 files changed, 31 deletions(-)

Change log:
- Originally posted here
  https://lore.kernel.org/r/20240610085555.88197-21-baolu.lu@linux.intel.com
  After several patches in that series were merged, this patch is
  targeted for 6.12-rc.

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index bd722f473635..62d1b85c80d3 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -785,7 +785,6 @@ static inline void iommu_iotlb_gather_init(struct iommu_iotlb_gather *gather)
 }
 
 extern int bus_iommu_probe(const struct bus_type *bus);
-extern bool iommu_present(const struct bus_type *bus);
 extern bool device_iommu_capable(struct device *dev, enum iommu_cap cap);
 extern bool iommu_group_has_isolated_msi(struct iommu_group *group);
 extern struct iommu_domain *iommu_domain_alloc(const struct bus_type *bus);
@@ -1081,11 +1080,6 @@ struct iommu_iotlb_gather {};
 struct iommu_dirty_bitmap {};
 struct iommu_dirty_ops {};
 
-static inline bool iommu_present(const struct bus_type *bus)
-{
-	return false;
-}
-
 static inline bool device_iommu_capable(struct device *dev, enum iommu_cap cap)
 {
 	return false;
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 83c8e617a2c5..7bfd2caaf33b 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1840,31 +1840,6 @@ int bus_iommu_probe(const struct bus_type *bus)
 	return 0;
 }
 
-/**
- * iommu_present() - make platform-specific assumptions about an IOMMU
- * @bus: bus to check
- *
- * Do not use this function. You want device_iommu_mapped() instead.
- *
- * Return: true if some IOMMU is present and aware of devices on the given bus;
- * in general it may not be the only IOMMU, and it may not have anything to do
- * with whatever device you are ultimately interested in.
- */
-bool iommu_present(const struct bus_type *bus)
-{
-	bool ret = false;
-
-	for (int i = 0; i < ARRAY_SIZE(iommu_buses); i++) {
-		if (iommu_buses[i] == bus) {
-			spin_lock(&iommu_device_lock);
-			ret = !list_empty(&iommu_device_list);
-			spin_unlock(&iommu_device_lock);
-		}
-	}
-	return ret;
-}
-EXPORT_SYMBOL_GPL(iommu_present);
-
 /**
  * device_iommu_capable() - check for a general IOMMU capability
  * @dev: device to which the capability would be relevant, if available
-- 
2.43.0

RE: [PATCH 1/1] iommu: Remove iommu_present()

[Tian, Kevin]

> From: Lu Baolu <baolu.lu@linux.intel.com>
> Sent: Monday, September 30, 2024 8:43 AM
> 
> The last callsite of iommu_present() is removed by commit <45c690aea8ee>
> ("drm/tegra: Use iommu_paging_domain_alloc()"). Remove it to avoid dead
> code.
> 
> Fixes: 45c690aea8ee ("drm/tegra: Use iommu_paging_domain_alloc()")
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Reviewed-by: Kevin Tian <kevin.tian@intel.com>

Re: [PATCH 1/1] iommu: Remove iommu_present()

[Yi Liu]

On 2024/9/30 08:42, Lu Baolu wrote:
> The last callsite of iommu_present() is removed by commit <45c690aea8ee>
> ("drm/tegra: Use iommu_paging_domain_alloc()"). Remove it to avoid dead
> code.
> 
> Fixes: 45c690aea8ee ("drm/tegra: Use iommu_paging_domain_alloc()")
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
> ---

just curious, why a fix tag here. It is not a bug. is it?

Reviewed-by: Yi Liu <yi.l.liu@intel.com>

>   include/linux/iommu.h |  6 ------
>   drivers/iommu/iommu.c | 25 -------------------------
>   2 files changed, 31 deletions(-)
> 
> Change log:
> - Originally posted here
>    https://lore.kernel.org/r/20240610085555.88197-21-baolu.lu@linux.intel.com
>    After several patches in that series were merged, this patch is
>    targeted for 6.12-rc.
> 
> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> index bd722f473635..62d1b85c80d3 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -785,7 +785,6 @@ static inline void iommu_iotlb_gather_init(struct iommu_iotlb_gather *gather)
>   }
>   
>   extern int bus_iommu_probe(const struct bus_type *bus);
> -extern bool iommu_present(const struct bus_type *bus);
>   extern bool device_iommu_capable(struct device *dev, enum iommu_cap cap);
>   extern bool iommu_group_has_isolated_msi(struct iommu_group *group);
>   extern struct iommu_domain *iommu_domain_alloc(const struct bus_type *bus);
> @@ -1081,11 +1080,6 @@ struct iommu_iotlb_gather {};
>   struct iommu_dirty_bitmap {};
>   struct iommu_dirty_ops {};
>   
> -static inline bool iommu_present(const struct bus_type *bus)
> -{
> -	return false;
> -}
> -
>   static inline bool device_iommu_capable(struct device *dev, enum iommu_cap cap)
>   {
>   	return false;
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index 83c8e617a2c5..7bfd2caaf33b 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -1840,31 +1840,6 @@ int bus_iommu_probe(const struct bus_type *bus)
>   	return 0;
>   }
>   
> -/**
> - * iommu_present() - make platform-specific assumptions about an IOMMU
> - * @bus: bus to check
> - *
> - * Do not use this function. You want device_iommu_mapped() instead.
> - *
> - * Return: true if some IOMMU is present and aware of devices on the given bus;
> - * in general it may not be the only IOMMU, and it may not have anything to do
> - * with whatever device you are ultimately interested in.
> - */
> -bool iommu_present(const struct bus_type *bus)
> -{
> -	bool ret = false;
> -
> -	for (int i = 0; i < ARRAY_SIZE(iommu_buses); i++) {
> -		if (iommu_buses[i] == bus) {
> -			spin_lock(&iommu_device_lock);
> -			ret = !list_empty(&iommu_device_list);
> -			spin_unlock(&iommu_device_lock);
> -		}
> -	}
> -	return ret;
> -}
> -EXPORT_SYMBOL_GPL(iommu_present);
> -
>   /**
>    * device_iommu_capable() - check for a general IOMMU capability
>    * @dev: device to which the capability would be relevant, if available

-- 
Regards,
Yi Liu

Re: [PATCH 1/1] iommu: Remove iommu_present()

[Jason Gunthorpe]

On Mon, Sep 30, 2024 at 08:42:35AM +0800, Lu Baolu wrote:
> The last callsite of iommu_present() is removed by commit <45c690aea8ee>
> ("drm/tegra: Use iommu_paging_domain_alloc()"). Remove it to avoid dead
> code.
> 
> Fixes: 45c690aea8ee ("drm/tegra: Use iommu_paging_domain_alloc()")
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
> ---
>  include/linux/iommu.h |  6 ------
>  drivers/iommu/iommu.c | 25 -------------------------
>  2 files changed, 31 deletions(-)

Also think the fixes should be removed

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Jason

Re: [PATCH 1/1] iommu: Remove iommu_present()

[Baolu Lu]

On 2024/10/2 1:54, Jason Gunthorpe wrote:
> On Mon, Sep 30, 2024 at 08:42:35AM +0800, Lu Baolu wrote:
>> The last callsite of iommu_present() is removed by commit <45c690aea8ee>
>> ("drm/tegra: Use iommu_paging_domain_alloc()"). Remove it to avoid dead
>> code.
>>
>> Fixes: 45c690aea8ee ("drm/tegra: Use iommu_paging_domain_alloc()")
>> Signed-off-by: Lu Baolu<baolu.lu@linux.intel.com>
>> Reviewed-by: Jason Gunthorpe<jgg@nvidia.com>
>> ---
>>   include/linux/iommu.h |  6 ------
>>   drivers/iommu/iommu.c | 25 -------------------------
>>   2 files changed, 31 deletions(-)
> Also think the fixes should be removed

Okay. I will send a v2 with the fixes tag removed.

Thanks,
baolu