Re: [PATCH 2/2] drm/cma-helper: Implement mmap as GEM CMA object functions

Re: [PATCH 2/2] drm/cma-helper: Implement mmap as GEM CMA object functions

[Kieran Bingham]

Hi Thomas,

On 23/11/2020 11:56, Thomas Zimmermann wrote:
> The new GEM object function drm_gem_cma_mmap() sets the VMA flags
> and offset as in the old implementation and immediately maps in the
> buffer's memory pages.
> 
> Changing CMA helpers to use the GEM object function allows for the
> removal of the special implementations for mmap and gem_prime_mmap
> callbacks. The regular functions drm_gem_mmap() and drm_gem_prime_mmap()
> are now used.

I've encountered a memory leak regression in our Renesas R-Car DU tests,
and git bisection has led me to this patch (as commit f5ca8eb6f9).

Running the tests sequentially, while grepping /proc/meminfo for Cma, it
is evident that CMA memory is not released, until exhausted and the
allocations fail (seen in [0]) shown by the error report:

>     self.fbs.append(pykms.DumbFramebuffer(self.card, mode.hdisplay, mode.vdisplay, "XR24"))
> ValueError: DRM_IOCTL_MODE_CREATE_DUMB failed: Cannot allocate memory


Failing tests at f5ca8eb6f9 can be seen at [0], while the tests pass
successfully [1] on the commit previous to that (bc2532ab7c2):

Reverting f5ca8eb6f9 also produces a successful pass [2]

 [0] https://paste.ubuntu.com/p/VjPGPgswxR/ # Failed at f5ca8eb6f9
 [1] https://paste.ubuntu.com/p/78RRp2WpNR/ # Success at bc2532ab7c2
 [2] https://paste.ubuntu.com/p/qJKjZZN2pt/ # Success with revert


I don't believe we handle mmap specially in the RCar-DU driver, so I
wonder if this issue has hit anyone else as well?

Any ideas of a repair without a revert ? Or do we just need to submit a
revert?

I've yet to fully understand the implications of the patch below.

Thanks
--
Regards

Kieran



> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---
>  drivers/gpu/drm/drm_file.c           |   3 +-
>  drivers/gpu/drm/drm_gem_cma_helper.c | 121 +++++++++------------------
>  drivers/gpu/drm/pl111/pl111_drv.c    |   2 +-
>  drivers/gpu/drm/vc4/vc4_bo.c         |   2 +-
>  include/drm/drm_gem_cma_helper.h     |  10 +--
>  5 files changed, 44 insertions(+), 94 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
> index b50380fa80ce..80886d50d0f1 100644
> --- a/drivers/gpu/drm/drm_file.c
> +++ b/drivers/gpu/drm/drm_file.c
> @@ -113,8 +113,7 @@ bool drm_dev_needs_global_mutex(struct drm_device *dev)
>   * The memory mapping implementation will vary depending on how the driver
>   * manages memory. Legacy drivers will use the deprecated drm_legacy_mmap()
>   * function, modern drivers should use one of the provided memory-manager
> - * specific implementations. For GEM-based drivers this is drm_gem_mmap(), and
> - * for drivers which use the CMA GEM helpers it's drm_gem_cma_mmap().
> + * specific implementations. For GEM-based drivers this is drm_gem_mmap().
>   *
>   * No other file operations are supported by the DRM userspace API. Overall the
>   * following is an example &file_operations structure::
> diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c b/drivers/gpu/drm/drm_gem_cma_helper.c
> index 6a4ef335ebc9..7942cf05cd93 100644
> --- a/drivers/gpu/drm/drm_gem_cma_helper.c
> +++ b/drivers/gpu/drm/drm_gem_cma_helper.c
> @@ -38,6 +38,7 @@ static const struct drm_gem_object_funcs drm_gem_cma_default_funcs = {
>  	.print_info = drm_gem_cma_print_info,
>  	.get_sg_table = drm_gem_cma_get_sg_table,
>  	.vmap = drm_gem_cma_vmap,
> +	.mmap = drm_gem_cma_mmap,
>  	.vm_ops = &drm_gem_cma_vm_ops,
>  };
>  
> @@ -277,62 +278,6 @@ const struct vm_operations_struct drm_gem_cma_vm_ops = {
>  };
>  EXPORT_SYMBOL_GPL(drm_gem_cma_vm_ops);
>  
> -static int drm_gem_cma_mmap_obj(struct drm_gem_cma_object *cma_obj,
> -				struct vm_area_struct *vma)
> -{
> -	int ret;
> -
> -	/*
> -	 * Clear the VM_PFNMAP flag that was set by drm_gem_mmap(), and set the
> -	 * vm_pgoff (used as a fake buffer offset by DRM) to 0 as we want to map
> -	 * the whole buffer.
> -	 */
> -	vma->vm_flags &= ~VM_PFNMAP;
> -	vma->vm_pgoff = 0;
> -
> -	ret = dma_mmap_wc(cma_obj->base.dev->dev, vma, cma_obj->vaddr,
> -			  cma_obj->paddr, vma->vm_end - vma->vm_start);
> -	if (ret)
> -		drm_gem_vm_close(vma);
> -
> -	return ret;
> -}
> -
> -/**
> - * drm_gem_cma_mmap - memory-map a CMA GEM object
> - * @filp: file object
> - * @vma: VMA for the area to be mapped
> - *
> - * This function implements an augmented version of the GEM DRM file mmap
> - * operation for CMA objects: In addition to the usual GEM VMA setup it
> - * immediately faults in the entire object instead of using on-demaind
> - * faulting. Drivers which employ the CMA helpers should use this function
> - * as their ->mmap() handler in the DRM device file's file_operations
> - * structure.
> - *
> - * Instead of directly referencing this function, drivers should use the
> - * DEFINE_DRM_GEM_CMA_FOPS().macro.
> - *
> - * Returns:
> - * 0 on success or a negative error code on failure.
> - */
> -int drm_gem_cma_mmap(struct file *filp, struct vm_area_struct *vma)
> -{
> -	struct drm_gem_cma_object *cma_obj;
> -	struct drm_gem_object *gem_obj;
> -	int ret;
> -
> -	ret = drm_gem_mmap(filp, vma);
> -	if (ret)
> -		return ret;
> -
> -	gem_obj = vma->vm_private_data;
> -	cma_obj = to_drm_gem_cma_obj(gem_obj);
> -
> -	return drm_gem_cma_mmap_obj(cma_obj, vma);
> -}
> -EXPORT_SYMBOL_GPL(drm_gem_cma_mmap);
> -
>  #ifndef CONFIG_MMU
>  /**
>   * drm_gem_cma_get_unmapped_area - propose address for mapping in noMMU cases
> @@ -500,33 +445,6 @@ drm_gem_cma_prime_import_sg_table(struct drm_device *dev,
>  }
>  EXPORT_SYMBOL_GPL(drm_gem_cma_prime_import_sg_table);
>  
> -/**
> - * drm_gem_cma_prime_mmap - memory-map an exported CMA GEM object
> - * @obj: GEM object
> - * @vma: VMA for the area to be mapped
> - *
> - * This function maps a buffer imported via DRM PRIME into a userspace
> - * process's address space. Drivers that use the CMA helpers should set this
> - * as their &drm_driver.gem_prime_mmap callback.
> - *
> - * Returns:
> - * 0 on success or a negative error code on failure.
> - */
> -int drm_gem_cma_prime_mmap(struct drm_gem_object *obj,
> -			   struct vm_area_struct *vma)
> -{
> -	struct drm_gem_cma_object *cma_obj;
> -	int ret;
> -
> -	ret = drm_gem_mmap_obj(obj, obj->size, vma);
> -	if (ret < 0)
> -		return ret;
> -
> -	cma_obj = to_drm_gem_cma_obj(obj);
> -	return drm_gem_cma_mmap_obj(cma_obj, vma);
> -}
> -EXPORT_SYMBOL_GPL(drm_gem_cma_prime_mmap);
> -
>  /**
>   * drm_gem_cma_vmap - map a CMA GEM object into the kernel's virtual
>   *     address space
> @@ -553,6 +471,43 @@ int drm_gem_cma_vmap(struct drm_gem_object *obj, struct dma_buf_map *map)
>  }
>  EXPORT_SYMBOL_GPL(drm_gem_cma_vmap);
>  
> +/**
> + * drm_gem_cma_mmap - memory-map an exported CMA GEM object
> + * @obj: GEM object
> + * @vma: VMA for the area to be mapped
> + *
> + * This function maps a buffer into a userspace process's address space.
> + * In addition to the usual GEM VMA setup it immediately faults in the entire
> + * object instead of using on-demand faulting. Drivers that use the CMA
> + * helpers should set this as their &drm_gem_object_funcs.mmap callback.
> + *
> + * Returns:
> + * 0 on success or a negative error code on failure.
> + */
> +int drm_gem_cma_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
> +{
> +	struct drm_gem_cma_object *cma_obj;
> +	int ret;
> +
> +	/*
> +	 * Clear the VM_PFNMAP flag that was set by drm_gem_mmap(), and set the
> +	 * vm_pgoff (used as a fake buffer offset by DRM) to 0 as we want to map
> +	 * the whole buffer.
> +	 */
> +	vma->vm_pgoff -= drm_vma_node_start(&obj->vma_node);
> +	vma->vm_flags &= ~VM_PFNMAP;
> +
> +	cma_obj = to_drm_gem_cma_obj(obj);
> +
> +	ret = dma_mmap_wc(cma_obj->base.dev->dev, vma, cma_obj->vaddr,
> +			  cma_obj->paddr, vma->vm_end - vma->vm_start);
> +	if (ret)
> +		drm_gem_vm_close(vma);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(drm_gem_cma_mmap);
> +
>  /**
>   * drm_gem_cma_prime_import_sg_table_vmap - PRIME import another driver's
>   *	scatter/gather table and get the virtual address of the buffer
> diff --git a/drivers/gpu/drm/pl111/pl111_drv.c b/drivers/gpu/drm/pl111/pl111_drv.c
> index 40e6708fbbe2..e4dcaef6c143 100644
> --- a/drivers/gpu/drm/pl111/pl111_drv.c
> +++ b/drivers/gpu/drm/pl111/pl111_drv.c
> @@ -228,7 +228,7 @@ static const struct drm_driver pl111_drm_driver = {
>  	.prime_handle_to_fd = drm_gem_prime_handle_to_fd,
>  	.prime_fd_to_handle = drm_gem_prime_fd_to_handle,
>  	.gem_prime_import_sg_table = pl111_gem_import_sg_table,
> -	.gem_prime_mmap = drm_gem_cma_prime_mmap,
> +	.gem_prime_mmap = drm_gem_prime_mmap,
>  
>  #if defined(CONFIG_DEBUG_FS)
>  	.debugfs_init = pl111_debugfs_init,
> diff --git a/drivers/gpu/drm/vc4/vc4_bo.c b/drivers/gpu/drm/vc4/vc4_bo.c
> index 813e6cb3f9af..dc316cb79e00 100644
> --- a/drivers/gpu/drm/vc4/vc4_bo.c
> +++ b/drivers/gpu/drm/vc4/vc4_bo.c
> @@ -782,7 +782,7 @@ int vc4_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
>  		return -EINVAL;
>  	}
>  
> -	return drm_gem_cma_prime_mmap(obj, vma);
> +	return drm_gem_prime_mmap(obj, vma);
>  }
>  
>  int vc4_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map)
> diff --git a/include/drm/drm_gem_cma_helper.h b/include/drm/drm_gem_cma_helper.h
> index 4680275ab339..0a9711caa3e8 100644
> --- a/include/drm/drm_gem_cma_helper.h
> +++ b/include/drm/drm_gem_cma_helper.h
> @@ -59,7 +59,7 @@ struct drm_gem_cma_object {
>  		.poll		= drm_poll,\
>  		.read		= drm_read,\
>  		.llseek		= noop_llseek,\
> -		.mmap		= drm_gem_cma_mmap,\
> +		.mmap		= drm_gem_mmap,\
>  		DRM_GEM_CMA_UNMAPPED_AREA_FOPS \
>  	}
>  
> @@ -76,9 +76,6 @@ int drm_gem_cma_dumb_create(struct drm_file *file_priv,
>  			    struct drm_device *drm,
>  			    struct drm_mode_create_dumb *args);
>  
> -/* set vm_flags and we can change the VM attribute to other one at here */
> -int drm_gem_cma_mmap(struct file *filp, struct vm_area_struct *vma);
> -
>  /* allocate physical memory */
>  struct drm_gem_cma_object *drm_gem_cma_create(struct drm_device *drm,
>  					      size_t size);
> @@ -101,9 +98,8 @@ struct drm_gem_object *
>  drm_gem_cma_prime_import_sg_table(struct drm_device *dev,
>  				  struct dma_buf_attachment *attach,
>  				  struct sg_table *sgt);
> -int drm_gem_cma_prime_mmap(struct drm_gem_object *obj,
> -			   struct vm_area_struct *vma);
>  int drm_gem_cma_vmap(struct drm_gem_object *obj, struct dma_buf_map *map);
> +int drm_gem_cma_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma);
>  
>  /**
>   * DRM_GEM_CMA_DRIVER_OPS_WITH_DUMB_CREATE - CMA GEM driver operations
> @@ -123,7 +119,7 @@ int drm_gem_cma_vmap(struct drm_gem_object *obj, struct dma_buf_map *map);
>  	.prime_handle_to_fd	= drm_gem_prime_handle_to_fd, \
>  	.prime_fd_to_handle	= drm_gem_prime_fd_to_handle, \
>  	.gem_prime_import_sg_table = drm_gem_cma_prime_import_sg_table, \
> -	.gem_prime_mmap		= drm_gem_cma_prime_mmap
> +	.gem_prime_mmap		= drm_gem_prime_mmap
>  
>  /**
>   * DRM_GEM_CMA_DRIVER_OPS - CMA GEM driver operations
> 

Re: [PATCH 2/2] drm/cma-helper: Implement mmap as GEM CMA object functions

[Thomas Zimmermann]

[-- Attachment #1.1.1: Type: text/plain, Size: 12295 bytes --]

Hi Kieran

Am 14.01.21 um 13:51 schrieb Kieran Bingham:
> Hi Thomas,
> 
> On 23/11/2020 11:56, Thomas Zimmermann wrote:
>> The new GEM object function drm_gem_cma_mmap() sets the VMA flags
>> and offset as in the old implementation and immediately maps in the
>> buffer's memory pages.
>>
>> Changing CMA helpers to use the GEM object function allows for the
>> removal of the special implementations for mmap and gem_prime_mmap
>> callbacks. The regular functions drm_gem_mmap() and drm_gem_prime_mmap()
>> are now used.
> 
> I've encountered a memory leak regression in our Renesas R-Car DU tests,
> and git bisection has led me to this patch (as commit f5ca8eb6f9).
> 
> Running the tests sequentially, while grepping /proc/meminfo for Cma, it
> is evident that CMA memory is not released, until exhausted and the
> allocations fail (seen in [0]) shown by the error report:
> 
>>      self.fbs.append(pykms.DumbFramebuffer(self.card, mode.hdisplay, mode.vdisplay, "XR24"))
>> ValueError: DRM_IOCTL_MODE_CREATE_DUMB failed: Cannot allocate memory
> 
> 
> Failing tests at f5ca8eb6f9 can be seen at [0], while the tests pass
> successfully [1] on the commit previous to that (bc2532ab7c2):
> 
> Reverting f5ca8eb6f9 also produces a successful pass [2]
> 
>   [0] https://paste.ubuntu.com/p/VjPGPgswxR/ # Failed at f5ca8eb6f9
>   [1] https://paste.ubuntu.com/p/78RRp2WpNR/ # Success at bc2532ab7c2
>   [2] https://paste.ubuntu.com/p/qJKjZZN2pt/ # Success with revert
> 
> 
> I don't believe we handle mmap specially in the RCar-DU driver, so I
> wonder if this issue has hit anyone else as well?
> 
> Any ideas of a repair without a revert ? Or do we just need to submit a
> revert?

I think we might not be setting the VMA ops and therefore not finalize 
the BO correctly. Could you please apply the attched (quick-and-dirty) 
patch and try again?

Best regards
Thomas

> 
> I've yet to fully understand the implications of the patch below.
> 
> Thanks
> --
> Regards
> 
> Kieran
> 
> 
> 
>> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
>> ---
>>   drivers/gpu/drm/drm_file.c           |   3 +-
>>   drivers/gpu/drm/drm_gem_cma_helper.c | 121 +++++++++------------------
>>   drivers/gpu/drm/pl111/pl111_drv.c    |   2 +-
>>   drivers/gpu/drm/vc4/vc4_bo.c         |   2 +-
>>   include/drm/drm_gem_cma_helper.h     |  10 +--
>>   5 files changed, 44 insertions(+), 94 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
>> index b50380fa80ce..80886d50d0f1 100644
>> --- a/drivers/gpu/drm/drm_file.c
>> +++ b/drivers/gpu/drm/drm_file.c
>> @@ -113,8 +113,7 @@ bool drm_dev_needs_global_mutex(struct drm_device *dev)
>>    * The memory mapping implementation will vary depending on how the driver
>>    * manages memory. Legacy drivers will use the deprecated drm_legacy_mmap()
>>    * function, modern drivers should use one of the provided memory-manager
>> - * specific implementations. For GEM-based drivers this is drm_gem_mmap(), and
>> - * for drivers which use the CMA GEM helpers it's drm_gem_cma_mmap().
>> + * specific implementations. For GEM-based drivers this is drm_gem_mmap().
>>    *
>>    * No other file operations are supported by the DRM userspace API. Overall the
>>    * following is an example &file_operations structure::
>> diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c b/drivers/gpu/drm/drm_gem_cma_helper.c
>> index 6a4ef335ebc9..7942cf05cd93 100644
>> --- a/drivers/gpu/drm/drm_gem_cma_helper.c
>> +++ b/drivers/gpu/drm/drm_gem_cma_helper.c
>> @@ -38,6 +38,7 @@ static const struct drm_gem_object_funcs drm_gem_cma_default_funcs = {
>>   	.print_info = drm_gem_cma_print_info,
>>   	.get_sg_table = drm_gem_cma_get_sg_table,
>>   	.vmap = drm_gem_cma_vmap,
>> +	.mmap = drm_gem_cma_mmap,
>>   	.vm_ops = &drm_gem_cma_vm_ops,
>>   };
>>   
>> @@ -277,62 +278,6 @@ const struct vm_operations_struct drm_gem_cma_vm_ops = {
>>   };
>>   EXPORT_SYMBOL_GPL(drm_gem_cma_vm_ops);
>>   
>> -static int drm_gem_cma_mmap_obj(struct drm_gem_cma_object *cma_obj,
>> -				struct vm_area_struct *vma)
>> -{
>> -	int ret;
>> -
>> -	/*
>> -	 * Clear the VM_PFNMAP flag that was set by drm_gem_mmap(), and set the
>> -	 * vm_pgoff (used as a fake buffer offset by DRM) to 0 as we want to map
>> -	 * the whole buffer.
>> -	 */
>> -	vma->vm_flags &= ~VM_PFNMAP;
>> -	vma->vm_pgoff = 0;
>> -
>> -	ret = dma_mmap_wc(cma_obj->base.dev->dev, vma, cma_obj->vaddr,
>> -			  cma_obj->paddr, vma->vm_end - vma->vm_start);
>> -	if (ret)
>> -		drm_gem_vm_close(vma);
>> -
>> -	return ret;
>> -}
>> -
>> -/**
>> - * drm_gem_cma_mmap - memory-map a CMA GEM object
>> - * @filp: file object
>> - * @vma: VMA for the area to be mapped
>> - *
>> - * This function implements an augmented version of the GEM DRM file mmap
>> - * operation for CMA objects: In addition to the usual GEM VMA setup it
>> - * immediately faults in the entire object instead of using on-demaind
>> - * faulting. Drivers which employ the CMA helpers should use this function
>> - * as their ->mmap() handler in the DRM device file's file_operations
>> - * structure.
>> - *
>> - * Instead of directly referencing this function, drivers should use the
>> - * DEFINE_DRM_GEM_CMA_FOPS().macro.
>> - *
>> - * Returns:
>> - * 0 on success or a negative error code on failure.
>> - */
>> -int drm_gem_cma_mmap(struct file *filp, struct vm_area_struct *vma)
>> -{
>> -	struct drm_gem_cma_object *cma_obj;
>> -	struct drm_gem_object *gem_obj;
>> -	int ret;
>> -
>> -	ret = drm_gem_mmap(filp, vma);
>> -	if (ret)
>> -		return ret;
>> -
>> -	gem_obj = vma->vm_private_data;
>> -	cma_obj = to_drm_gem_cma_obj(gem_obj);
>> -
>> -	return drm_gem_cma_mmap_obj(cma_obj, vma);
>> -}
>> -EXPORT_SYMBOL_GPL(drm_gem_cma_mmap);
>> -
>>   #ifndef CONFIG_MMU
>>   /**
>>    * drm_gem_cma_get_unmapped_area - propose address for mapping in noMMU cases
>> @@ -500,33 +445,6 @@ drm_gem_cma_prime_import_sg_table(struct drm_device *dev,
>>   }
>>   EXPORT_SYMBOL_GPL(drm_gem_cma_prime_import_sg_table);
>>   
>> -/**
>> - * drm_gem_cma_prime_mmap - memory-map an exported CMA GEM object
>> - * @obj: GEM object
>> - * @vma: VMA for the area to be mapped
>> - *
>> - * This function maps a buffer imported via DRM PRIME into a userspace
>> - * process's address space. Drivers that use the CMA helpers should set this
>> - * as their &drm_driver.gem_prime_mmap callback.
>> - *
>> - * Returns:
>> - * 0 on success or a negative error code on failure.
>> - */
>> -int drm_gem_cma_prime_mmap(struct drm_gem_object *obj,
>> -			   struct vm_area_struct *vma)
>> -{
>> -	struct drm_gem_cma_object *cma_obj;
>> -	int ret;
>> -
>> -	ret = drm_gem_mmap_obj(obj, obj->size, vma);
>> -	if (ret < 0)
>> -		return ret;
>> -
>> -	cma_obj = to_drm_gem_cma_obj(obj);
>> -	return drm_gem_cma_mmap_obj(cma_obj, vma);
>> -}
>> -EXPORT_SYMBOL_GPL(drm_gem_cma_prime_mmap);
>> -
>>   /**
>>    * drm_gem_cma_vmap - map a CMA GEM object into the kernel's virtual
>>    *     address space
>> @@ -553,6 +471,43 @@ int drm_gem_cma_vmap(struct drm_gem_object *obj, struct dma_buf_map *map)
>>   }
>>   EXPORT_SYMBOL_GPL(drm_gem_cma_vmap);
>>   
>> +/**
>> + * drm_gem_cma_mmap - memory-map an exported CMA GEM object
>> + * @obj: GEM object
>> + * @vma: VMA for the area to be mapped
>> + *
>> + * This function maps a buffer into a userspace process's address space.
>> + * In addition to the usual GEM VMA setup it immediately faults in the entire
>> + * object instead of using on-demand faulting. Drivers that use the CMA
>> + * helpers should set this as their &drm_gem_object_funcs.mmap callback.
>> + *
>> + * Returns:
>> + * 0 on success or a negative error code on failure.
>> + */
>> +int drm_gem_cma_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
>> +{
>> +	struct drm_gem_cma_object *cma_obj;
>> +	int ret;
>> +
>> +	/*
>> +	 * Clear the VM_PFNMAP flag that was set by drm_gem_mmap(), and set the
>> +	 * vm_pgoff (used as a fake buffer offset by DRM) to 0 as we want to map
>> +	 * the whole buffer.
>> +	 */
>> +	vma->vm_pgoff -= drm_vma_node_start(&obj->vma_node);
>> +	vma->vm_flags &= ~VM_PFNMAP;
>> +
>> +	cma_obj = to_drm_gem_cma_obj(obj);
>> +
>> +	ret = dma_mmap_wc(cma_obj->base.dev->dev, vma, cma_obj->vaddr,
>> +			  cma_obj->paddr, vma->vm_end - vma->vm_start);
>> +	if (ret)
>> +		drm_gem_vm_close(vma);
>> +
>> +	return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(drm_gem_cma_mmap);
>> +
>>   /**
>>    * drm_gem_cma_prime_import_sg_table_vmap - PRIME import another driver's
>>    *	scatter/gather table and get the virtual address of the buffer
>> diff --git a/drivers/gpu/drm/pl111/pl111_drv.c b/drivers/gpu/drm/pl111/pl111_drv.c
>> index 40e6708fbbe2..e4dcaef6c143 100644
>> --- a/drivers/gpu/drm/pl111/pl111_drv.c
>> +++ b/drivers/gpu/drm/pl111/pl111_drv.c
>> @@ -228,7 +228,7 @@ static const struct drm_driver pl111_drm_driver = {
>>   	.prime_handle_to_fd = drm_gem_prime_handle_to_fd,
>>   	.prime_fd_to_handle = drm_gem_prime_fd_to_handle,
>>   	.gem_prime_import_sg_table = pl111_gem_import_sg_table,
>> -	.gem_prime_mmap = drm_gem_cma_prime_mmap,
>> +	.gem_prime_mmap = drm_gem_prime_mmap,
>>   
>>   #if defined(CONFIG_DEBUG_FS)
>>   	.debugfs_init = pl111_debugfs_init,
>> diff --git a/drivers/gpu/drm/vc4/vc4_bo.c b/drivers/gpu/drm/vc4/vc4_bo.c
>> index 813e6cb3f9af..dc316cb79e00 100644
>> --- a/drivers/gpu/drm/vc4/vc4_bo.c
>> +++ b/drivers/gpu/drm/vc4/vc4_bo.c
>> @@ -782,7 +782,7 @@ int vc4_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
>>   		return -EINVAL;
>>   	}
>>   
>> -	return drm_gem_cma_prime_mmap(obj, vma);
>> +	return drm_gem_prime_mmap(obj, vma);
>>   }
>>   
>>   int vc4_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map)
>> diff --git a/include/drm/drm_gem_cma_helper.h b/include/drm/drm_gem_cma_helper.h
>> index 4680275ab339..0a9711caa3e8 100644
>> --- a/include/drm/drm_gem_cma_helper.h
>> +++ b/include/drm/drm_gem_cma_helper.h
>> @@ -59,7 +59,7 @@ struct drm_gem_cma_object {
>>   		.poll		= drm_poll,\
>>   		.read		= drm_read,\
>>   		.llseek		= noop_llseek,\
>> -		.mmap		= drm_gem_cma_mmap,\
>> +		.mmap		= drm_gem_mmap,\
>>   		DRM_GEM_CMA_UNMAPPED_AREA_FOPS \
>>   	}
>>   
>> @@ -76,9 +76,6 @@ int drm_gem_cma_dumb_create(struct drm_file *file_priv,
>>   			    struct drm_device *drm,
>>   			    struct drm_mode_create_dumb *args);
>>   
>> -/* set vm_flags and we can change the VM attribute to other one at here */
>> -int drm_gem_cma_mmap(struct file *filp, struct vm_area_struct *vma);
>> -
>>   /* allocate physical memory */
>>   struct drm_gem_cma_object *drm_gem_cma_create(struct drm_device *drm,
>>   					      size_t size);
>> @@ -101,9 +98,8 @@ struct drm_gem_object *
>>   drm_gem_cma_prime_import_sg_table(struct drm_device *dev,
>>   				  struct dma_buf_attachment *attach,
>>   				  struct sg_table *sgt);
>> -int drm_gem_cma_prime_mmap(struct drm_gem_object *obj,
>> -			   struct vm_area_struct *vma);
>>   int drm_gem_cma_vmap(struct drm_gem_object *obj, struct dma_buf_map *map);
>> +int drm_gem_cma_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma);
>>   
>>   /**
>>    * DRM_GEM_CMA_DRIVER_OPS_WITH_DUMB_CREATE - CMA GEM driver operations
>> @@ -123,7 +119,7 @@ int drm_gem_cma_vmap(struct drm_gem_object *obj, struct dma_buf_map *map);
>>   	.prime_handle_to_fd	= drm_gem_prime_handle_to_fd, \
>>   	.prime_fd_to_handle	= drm_gem_prime_fd_to_handle, \
>>   	.gem_prime_import_sg_table = drm_gem_cma_prime_import_sg_table, \
>> -	.gem_prime_mmap		= drm_gem_cma_prime_mmap
>> +	.gem_prime_mmap		= drm_gem_prime_mmap
>>   
>>   /**
>>    * DRM_GEM_CMA_DRIVER_OPS - CMA GEM driver operations
>>
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer

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From d0583fe22cd0cd29749ff679e46e13b58de325cb Mon Sep 17 00:00:00 2001
From: Thomas Zimmermann <tzimmermann@suse.de>
Date: Thu, 14 Jan 2021 14:21:51 +0100
Subject: [PATCH] drm/cma: Set vma ops in mmap function

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/gpu/drm/drm_gem_cma_helper.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c b/drivers/gpu/drm/drm_gem_cma_helper.c
index 7942cf05cd93..0bd192736169 100644
--- a/drivers/gpu/drm/drm_gem_cma_helper.c
+++ b/drivers/gpu/drm/drm_gem_cma_helper.c
@@ -489,6 +489,8 @@ int drm_gem_cma_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
 	struct drm_gem_cma_object *cma_obj;
 	int ret;
 
+	vma->vm_ops = obj->funcs->vm_ops;
+
 	/*
 	 * Clear the VM_PFNMAP flag that was set by drm_gem_mmap(), and set the
 	 * vm_pgoff (used as a fake buffer offset by DRM) to 0 as we want to map
-- 
2.29.2


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Re: [PATCH 2/2] drm/cma-helper: Implement mmap as GEM CMA object functions

[Kieran Bingham]

Hi Thomas,

On 14/01/2021 13:26, Thomas Zimmermann wrote:
> Hi Kieran
> 
> Am 14.01.21 um 13:51 schrieb Kieran Bingham:
>> Hi Thomas,
>>
>> On 23/11/2020 11:56, Thomas Zimmermann wrote:
>>> The new GEM object function drm_gem_cma_mmap() sets the VMA flags
>>> and offset as in the old implementation and immediately maps in the
>>> buffer's memory pages.
>>>
>>> Changing CMA helpers to use the GEM object function allows for the
>>> removal of the special implementations for mmap and gem_prime_mmap
>>> callbacks. The regular functions drm_gem_mmap() and drm_gem_prime_mmap()
>>> are now used.
>>
>> I've encountered a memory leak regression in our Renesas R-Car DU tests,
>> and git bisection has led me to this patch (as commit f5ca8eb6f9).
>>
>> Running the tests sequentially, while grepping /proc/meminfo for Cma, it
>> is evident that CMA memory is not released, until exhausted and the
>> allocations fail (seen in [0]) shown by the error report:
>>
>>>      self.fbs.append(pykms.DumbFramebuffer(self.card, mode.hdisplay,
>>> mode.vdisplay, "XR24"))
>>> ValueError: DRM_IOCTL_MODE_CREATE_DUMB failed: Cannot allocate memory
>>
>>
>> Failing tests at f5ca8eb6f9 can be seen at [0], while the tests pass
>> successfully [1] on the commit previous to that (bc2532ab7c2):
>>
>> Reverting f5ca8eb6f9 also produces a successful pass [2]
>>
>>   [0] https://paste.ubuntu.com/p/VjPGPgswxR/ # Failed at f5ca8eb6f9
>>   [1] https://paste.ubuntu.com/p/78RRp2WpNR/ # Success at bc2532ab7c2
>>   [2] https://paste.ubuntu.com/p/qJKjZZN2pt/ # Success with revert
>>
>>
>> I don't believe we handle mmap specially in the RCar-DU driver, so I
>> wonder if this issue has hit anyone else as well?
>>
>> Any ideas of a repair without a revert ? Or do we just need to submit a
>> revert?
> 
> I think we might not be setting the VMA ops and therefore not finalize
> the BO correctly. Could you please apply the attched (quick-and-dirty)
> patch and try again?

Thanks for the quick response.

I can confirm the quick-and-dirty patch resolves the issue:
  https://paste.ubuntu.com/p/sKDp3dNvwV/

You can add a
Tested-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>

if it stays like that, but I suspect there might be a better place to
initialise the ops rather than in the mmap call itself.

Happy to do further testing as required.

--
Regards

Kieran


> Best regards
> Thomas
> 
>>
>> I've yet to fully understand the implications of the patch below.
>>
>> Thanks
>> -- 
>> Regards
>>
>> Kieran
>>
>>
>>
>>> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
>>> ---
>>>   drivers/gpu/drm/drm_file.c           |   3 +-
>>>   drivers/gpu/drm/drm_gem_cma_helper.c | 121 +++++++++------------------
>>>   drivers/gpu/drm/pl111/pl111_drv.c    |   2 +-
>>>   drivers/gpu/drm/vc4/vc4_bo.c         |   2 +-
>>>   include/drm/drm_gem_cma_helper.h     |  10 +--
>>>   5 files changed, 44 insertions(+), 94 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
>>> index b50380fa80ce..80886d50d0f1 100644
>>> --- a/drivers/gpu/drm/drm_file.c
>>> +++ b/drivers/gpu/drm/drm_file.c
>>> @@ -113,8 +113,7 @@ bool drm_dev_needs_global_mutex(struct drm_device
>>> *dev)
>>>    * The memory mapping implementation will vary depending on how the
>>> driver
>>>    * manages memory. Legacy drivers will use the deprecated
>>> drm_legacy_mmap()
>>>    * function, modern drivers should use one of the provided
>>> memory-manager
>>> - * specific implementations. For GEM-based drivers this is
>>> drm_gem_mmap(), and
>>> - * for drivers which use the CMA GEM helpers it's drm_gem_cma_mmap().
>>> + * specific implementations. For GEM-based drivers this is
>>> drm_gem_mmap().
>>>    *
>>>    * No other file operations are supported by the DRM userspace API.
>>> Overall the
>>>    * following is an example &file_operations structure::
>>> diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c
>>> b/drivers/gpu/drm/drm_gem_cma_helper.c
>>> index 6a4ef335ebc9..7942cf05cd93 100644
>>> --- a/drivers/gpu/drm/drm_gem_cma_helper.c
>>> +++ b/drivers/gpu/drm/drm_gem_cma_helper.c
>>> @@ -38,6 +38,7 @@ static const struct drm_gem_object_funcs
>>> drm_gem_cma_default_funcs = {
>>>       .print_info = drm_gem_cma_print_info,
>>>       .get_sg_table = drm_gem_cma_get_sg_table,
>>>       .vmap = drm_gem_cma_vmap,
>>> +    .mmap = drm_gem_cma_mmap,
>>>       .vm_ops = &drm_gem_cma_vm_ops,
>>>   };
>>>   @@ -277,62 +278,6 @@ const struct vm_operations_struct
>>> drm_gem_cma_vm_ops = {
>>>   };
>>>   EXPORT_SYMBOL_GPL(drm_gem_cma_vm_ops);
>>>   -static int drm_gem_cma_mmap_obj(struct drm_gem_cma_object *cma_obj,
>>> -                struct vm_area_struct *vma)
>>> -{
>>> -    int ret;
>>> -
>>> -    /*
>>> -     * Clear the VM_PFNMAP flag that was set by drm_gem_mmap(), and
>>> set the
>>> -     * vm_pgoff (used as a fake buffer offset by DRM) to 0 as we
>>> want to map
>>> -     * the whole buffer.
>>> -     */
>>> -    vma->vm_flags &= ~VM_PFNMAP;
>>> -    vma->vm_pgoff = 0;
>>> -
>>> -    ret = dma_mmap_wc(cma_obj->base.dev->dev, vma, cma_obj->vaddr,
>>> -              cma_obj->paddr, vma->vm_end - vma->vm_start);
>>> -    if (ret)
>>> -        drm_gem_vm_close(vma);
>>> -
>>> -    return ret;
>>> -}
>>> -
>>> -/**
>>> - * drm_gem_cma_mmap - memory-map a CMA GEM object
>>> - * @filp: file object
>>> - * @vma: VMA for the area to be mapped
>>> - *
>>> - * This function implements an augmented version of the GEM DRM file
>>> mmap
>>> - * operation for CMA objects: In addition to the usual GEM VMA setup it
>>> - * immediately faults in the entire object instead of using on-demaind
>>> - * faulting. Drivers which employ the CMA helpers should use this
>>> function
>>> - * as their ->mmap() handler in the DRM device file's file_operations
>>> - * structure.
>>> - *
>>> - * Instead of directly referencing this function, drivers should use
>>> the
>>> - * DEFINE_DRM_GEM_CMA_FOPS().macro.
>>> - *
>>> - * Returns:
>>> - * 0 on success or a negative error code on failure.
>>> - */
>>> -int drm_gem_cma_mmap(struct file *filp, struct vm_area_struct *vma)
>>> -{
>>> -    struct drm_gem_cma_object *cma_obj;
>>> -    struct drm_gem_object *gem_obj;
>>> -    int ret;
>>> -
>>> -    ret = drm_gem_mmap(filp, vma);
>>> -    if (ret)
>>> -        return ret;
>>> -
>>> -    gem_obj = vma->vm_private_data;
>>> -    cma_obj = to_drm_gem_cma_obj(gem_obj);
>>> -
>>> -    return drm_gem_cma_mmap_obj(cma_obj, vma);
>>> -}
>>> -EXPORT_SYMBOL_GPL(drm_gem_cma_mmap);
>>> -
>>>   #ifndef CONFIG_MMU
>>>   /**
>>>    * drm_gem_cma_get_unmapped_area - propose address for mapping in
>>> noMMU cases
>>> @@ -500,33 +445,6 @@ drm_gem_cma_prime_import_sg_table(struct
>>> drm_device *dev,
>>>   }
>>>   EXPORT_SYMBOL_GPL(drm_gem_cma_prime_import_sg_table);
>>>   -/**
>>> - * drm_gem_cma_prime_mmap - memory-map an exported CMA GEM object
>>> - * @obj: GEM object
>>> - * @vma: VMA for the area to be mapped
>>> - *
>>> - * This function maps a buffer imported via DRM PRIME into a userspace
>>> - * process's address space. Drivers that use the CMA helpers should
>>> set this
>>> - * as their &drm_driver.gem_prime_mmap callback.
>>> - *
>>> - * Returns:
>>> - * 0 on success or a negative error code on failure.
>>> - */
>>> -int drm_gem_cma_prime_mmap(struct drm_gem_object *obj,
>>> -               struct vm_area_struct *vma)
>>> -{
>>> -    struct drm_gem_cma_object *cma_obj;
>>> -    int ret;
>>> -
>>> -    ret = drm_gem_mmap_obj(obj, obj->size, vma);
>>> -    if (ret < 0)
>>> -        return ret;
>>> -
>>> -    cma_obj = to_drm_gem_cma_obj(obj);
>>> -    return drm_gem_cma_mmap_obj(cma_obj, vma);
>>> -}
>>> -EXPORT_SYMBOL_GPL(drm_gem_cma_prime_mmap);
>>> -
>>>   /**
>>>    * drm_gem_cma_vmap - map a CMA GEM object into the kernel's virtual
>>>    *     address space
>>> @@ -553,6 +471,43 @@ int drm_gem_cma_vmap(struct drm_gem_object *obj,
>>> struct dma_buf_map *map)
>>>   }
>>>   EXPORT_SYMBOL_GPL(drm_gem_cma_vmap);
>>>   +/**
>>> + * drm_gem_cma_mmap - memory-map an exported CMA GEM object
>>> + * @obj: GEM object
>>> + * @vma: VMA for the area to be mapped
>>> + *
>>> + * This function maps a buffer into a userspace process's address
>>> space.
>>> + * In addition to the usual GEM VMA setup it immediately faults in
>>> the entire
>>> + * object instead of using on-demand faulting. Drivers that use the CMA
>>> + * helpers should set this as their &drm_gem_object_funcs.mmap
>>> callback.
>>> + *
>>> + * Returns:
>>> + * 0 on success or a negative error code on failure.
>>> + */
>>> +int drm_gem_cma_mmap(struct drm_gem_object *obj, struct
>>> vm_area_struct *vma)
>>> +{
>>> +    struct drm_gem_cma_object *cma_obj;
>>> +    int ret;
>>> +
>>> +    /*
>>> +     * Clear the VM_PFNMAP flag that was set by drm_gem_mmap(), and
>>> set the
>>> +     * vm_pgoff (used as a fake buffer offset by DRM) to 0 as we
>>> want to map
>>> +     * the whole buffer.
>>> +     */
>>> +    vma->vm_pgoff -= drm_vma_node_start(&obj->vma_node);
>>> +    vma->vm_flags &= ~VM_PFNMAP;
>>> +
>>> +    cma_obj = to_drm_gem_cma_obj(obj);
>>> +
>>> +    ret = dma_mmap_wc(cma_obj->base.dev->dev, vma, cma_obj->vaddr,
>>> +              cma_obj->paddr, vma->vm_end - vma->vm_start);
>>> +    if (ret)
>>> +        drm_gem_vm_close(vma);
>>> +
>>> +    return ret;
>>> +}
>>> +EXPORT_SYMBOL_GPL(drm_gem_cma_mmap);
>>> +
>>>   /**
>>>    * drm_gem_cma_prime_import_sg_table_vmap - PRIME import another
>>> driver's
>>>    *    scatter/gather table and get the virtual address of the buffer
>>> diff --git a/drivers/gpu/drm/pl111/pl111_drv.c
>>> b/drivers/gpu/drm/pl111/pl111_drv.c
>>> index 40e6708fbbe2..e4dcaef6c143 100644
>>> --- a/drivers/gpu/drm/pl111/pl111_drv.c
>>> +++ b/drivers/gpu/drm/pl111/pl111_drv.c
>>> @@ -228,7 +228,7 @@ static const struct drm_driver pl111_drm_driver = {
>>>       .prime_handle_to_fd = drm_gem_prime_handle_to_fd,
>>>       .prime_fd_to_handle = drm_gem_prime_fd_to_handle,
>>>       .gem_prime_import_sg_table = pl111_gem_import_sg_table,
>>> -    .gem_prime_mmap = drm_gem_cma_prime_mmap,
>>> +    .gem_prime_mmap = drm_gem_prime_mmap,
>>>     #if defined(CONFIG_DEBUG_FS)
>>>       .debugfs_init = pl111_debugfs_init,
>>> diff --git a/drivers/gpu/drm/vc4/vc4_bo.c b/drivers/gpu/drm/vc4/vc4_bo.c
>>> index 813e6cb3f9af..dc316cb79e00 100644
>>> --- a/drivers/gpu/drm/vc4/vc4_bo.c
>>> +++ b/drivers/gpu/drm/vc4/vc4_bo.c
>>> @@ -782,7 +782,7 @@ int vc4_prime_mmap(struct drm_gem_object *obj,
>>> struct vm_area_struct *vma)
>>>           return -EINVAL;
>>>       }
>>>   -    return drm_gem_cma_prime_mmap(obj, vma);
>>> +    return drm_gem_prime_mmap(obj, vma);
>>>   }
>>>     int vc4_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map
>>> *map)
>>> diff --git a/include/drm/drm_gem_cma_helper.h
>>> b/include/drm/drm_gem_cma_helper.h
>>> index 4680275ab339..0a9711caa3e8 100644
>>> --- a/include/drm/drm_gem_cma_helper.h
>>> +++ b/include/drm/drm_gem_cma_helper.h
>>> @@ -59,7 +59,7 @@ struct drm_gem_cma_object {
>>>           .poll        = drm_poll,\
>>>           .read        = drm_read,\
>>>           .llseek        = noop_llseek,\
>>> -        .mmap        = drm_gem_cma_mmap,\
>>> +        .mmap        = drm_gem_mmap,\
>>>           DRM_GEM_CMA_UNMAPPED_AREA_FOPS \
>>>       }
>>>   @@ -76,9 +76,6 @@ int drm_gem_cma_dumb_create(struct drm_file
>>> *file_priv,
>>>                   struct drm_device *drm,
>>>                   struct drm_mode_create_dumb *args);
>>>   -/* set vm_flags and we can change the VM attribute to other one at
>>> here */
>>> -int drm_gem_cma_mmap(struct file *filp, struct vm_area_struct *vma);
>>> -
>>>   /* allocate physical memory */
>>>   struct drm_gem_cma_object *drm_gem_cma_create(struct drm_device *drm,
>>>                             size_t size);
>>> @@ -101,9 +98,8 @@ struct drm_gem_object *
>>>   drm_gem_cma_prime_import_sg_table(struct drm_device *dev,
>>>                     struct dma_buf_attachment *attach,
>>>                     struct sg_table *sgt);
>>> -int drm_gem_cma_prime_mmap(struct drm_gem_object *obj,
>>> -               struct vm_area_struct *vma);
>>>   int drm_gem_cma_vmap(struct drm_gem_object *obj, struct dma_buf_map
>>> *map);
>>> +int drm_gem_cma_mmap(struct drm_gem_object *obj, struct
>>> vm_area_struct *vma);
>>>     /**
>>>    * DRM_GEM_CMA_DRIVER_OPS_WITH_DUMB_CREATE - CMA GEM driver operations
>>> @@ -123,7 +119,7 @@ int drm_gem_cma_vmap(struct drm_gem_object *obj,
>>> struct dma_buf_map *map);
>>>       .prime_handle_to_fd    = drm_gem_prime_handle_to_fd, \
>>>       .prime_fd_to_handle    = drm_gem_prime_fd_to_handle, \
>>>       .gem_prime_import_sg_table = drm_gem_cma_prime_import_sg_table, \
>>> -    .gem_prime_mmap        = drm_gem_cma_prime_mmap
>>> +    .gem_prime_mmap        = drm_gem_prime_mmap
>>>     /**
>>>    * DRM_GEM_CMA_DRIVER_OPS - CMA GEM driver operations
>>>
>>
>> _______________________________________________
>> dri-devel mailing list
>> dri-devel@lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/dri-devel
>>
> 

Re: [PATCH 2/2] drm/cma-helper: Implement mmap as GEM CMA object functions

[Thomas Zimmermann]

[-- Attachment #1.1: Type: text/plain, Size: 15114 bytes --]

Hi

Am 14.01.21 um 15:34 schrieb Kieran Bingham:
> Hi Thomas,
> 
> On 14/01/2021 13:26, Thomas Zimmermann wrote:
>> Hi Kieran
>>
>> Am 14.01.21 um 13:51 schrieb Kieran Bingham:
>>> Hi Thomas,
>>>
>>> On 23/11/2020 11:56, Thomas Zimmermann wrote:
>>>> The new GEM object function drm_gem_cma_mmap() sets the VMA flags
>>>> and offset as in the old implementation and immediately maps in the
>>>> buffer's memory pages.
>>>>
>>>> Changing CMA helpers to use the GEM object function allows for the
>>>> removal of the special implementations for mmap and gem_prime_mmap
>>>> callbacks. The regular functions drm_gem_mmap() and drm_gem_prime_mmap()
>>>> are now used.
>>>
>>> I've encountered a memory leak regression in our Renesas R-Car DU tests,
>>> and git bisection has led me to this patch (as commit f5ca8eb6f9).
>>>
>>> Running the tests sequentially, while grepping /proc/meminfo for Cma, it
>>> is evident that CMA memory is not released, until exhausted and the
>>> allocations fail (seen in [0]) shown by the error report:
>>>
>>>>       self.fbs.append(pykms.DumbFramebuffer(self.card, mode.hdisplay,
>>>> mode.vdisplay, "XR24"))
>>>> ValueError: DRM_IOCTL_MODE_CREATE_DUMB failed: Cannot allocate memory
>>>
>>>
>>> Failing tests at f5ca8eb6f9 can be seen at [0], while the tests pass
>>> successfully [1] on the commit previous to that (bc2532ab7c2):
>>>
>>> Reverting f5ca8eb6f9 also produces a successful pass [2]
>>>
>>>    [0] https://paste.ubuntu.com/p/VjPGPgswxR/ # Failed at f5ca8eb6f9
>>>    [1] https://paste.ubuntu.com/p/78RRp2WpNR/ # Success at bc2532ab7c2
>>>    [2] https://paste.ubuntu.com/p/qJKjZZN2pt/ # Success with revert
>>>
>>>
>>> I don't believe we handle mmap specially in the RCar-DU driver, so I
>>> wonder if this issue has hit anyone else as well?
>>>
>>> Any ideas of a repair without a revert ? Or do we just need to submit a
>>> revert?
>>
>> I think we might not be setting the VMA ops and therefore not finalize
>> the BO correctly. Could you please apply the attched (quick-and-dirty)
>> patch and try again?
> 
> Thanks for the quick response.
> 
> I can confirm the quick-and-dirty patch resolves the issue:
>    https://paste.ubuntu.com/p/sKDp3dNvwV/
> 
> You can add a
> Tested-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>

Great! If you don't mind, I'd also add you in the Reported-by tag.

> 
> if it stays like that, but I suspect there might be a better place to
> initialise the ops rather than in the mmap call itself.

I think that's the fix, basically. We could put such a line as a 
fall-back somewhere into the DRM core code. But I don't know if this 
really works with all drivers. Maybe there's one that requires vm_ops to 
be NULL.

Thanks for reporting this issue and testing quickly.

Best regards
Thomas

> 
> Happy to do further testing as required.
> 
> --
> Regards
> 
> Kieran
> 
> 
>> Best regards
>> Thomas
>>
>>>
>>> I've yet to fully understand the implications of the patch below.
>>>
>>> Thanks
>>> -- 
>>> Regards
>>>
>>> Kieran
>>>
>>>
>>>
>>>> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
>>>> ---
>>>>    drivers/gpu/drm/drm_file.c           |   3 +-
>>>>    drivers/gpu/drm/drm_gem_cma_helper.c | 121 +++++++++------------------
>>>>    drivers/gpu/drm/pl111/pl111_drv.c    |   2 +-
>>>>    drivers/gpu/drm/vc4/vc4_bo.c         |   2 +-
>>>>    include/drm/drm_gem_cma_helper.h     |  10 +--
>>>>    5 files changed, 44 insertions(+), 94 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
>>>> index b50380fa80ce..80886d50d0f1 100644
>>>> --- a/drivers/gpu/drm/drm_file.c
>>>> +++ b/drivers/gpu/drm/drm_file.c
>>>> @@ -113,8 +113,7 @@ bool drm_dev_needs_global_mutex(struct drm_device
>>>> *dev)
>>>>     * The memory mapping implementation will vary depending on how the
>>>> driver
>>>>     * manages memory. Legacy drivers will use the deprecated
>>>> drm_legacy_mmap()
>>>>     * function, modern drivers should use one of the provided
>>>> memory-manager
>>>> - * specific implementations. For GEM-based drivers this is
>>>> drm_gem_mmap(), and
>>>> - * for drivers which use the CMA GEM helpers it's drm_gem_cma_mmap().
>>>> + * specific implementations. For GEM-based drivers this is
>>>> drm_gem_mmap().
>>>>     *
>>>>     * No other file operations are supported by the DRM userspace API.
>>>> Overall the
>>>>     * following is an example &file_operations structure::
>>>> diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c
>>>> b/drivers/gpu/drm/drm_gem_cma_helper.c
>>>> index 6a4ef335ebc9..7942cf05cd93 100644
>>>> --- a/drivers/gpu/drm/drm_gem_cma_helper.c
>>>> +++ b/drivers/gpu/drm/drm_gem_cma_helper.c
>>>> @@ -38,6 +38,7 @@ static const struct drm_gem_object_funcs
>>>> drm_gem_cma_default_funcs = {
>>>>        .print_info = drm_gem_cma_print_info,
>>>>        .get_sg_table = drm_gem_cma_get_sg_table,
>>>>        .vmap = drm_gem_cma_vmap,
>>>> +    .mmap = drm_gem_cma_mmap,
>>>>        .vm_ops = &drm_gem_cma_vm_ops,
>>>>    };
>>>>    @@ -277,62 +278,6 @@ const struct vm_operations_struct
>>>> drm_gem_cma_vm_ops = {
>>>>    };
>>>>    EXPORT_SYMBOL_GPL(drm_gem_cma_vm_ops);
>>>>    -static int drm_gem_cma_mmap_obj(struct drm_gem_cma_object *cma_obj,
>>>> -                struct vm_area_struct *vma)
>>>> -{
>>>> -    int ret;
>>>> -
>>>> -    /*
>>>> -     * Clear the VM_PFNMAP flag that was set by drm_gem_mmap(), and
>>>> set the
>>>> -     * vm_pgoff (used as a fake buffer offset by DRM) to 0 as we
>>>> want to map
>>>> -     * the whole buffer.
>>>> -     */
>>>> -    vma->vm_flags &= ~VM_PFNMAP;
>>>> -    vma->vm_pgoff = 0;
>>>> -
>>>> -    ret = dma_mmap_wc(cma_obj->base.dev->dev, vma, cma_obj->vaddr,
>>>> -              cma_obj->paddr, vma->vm_end - vma->vm_start);
>>>> -    if (ret)
>>>> -        drm_gem_vm_close(vma);
>>>> -
>>>> -    return ret;
>>>> -}
>>>> -
>>>> -/**
>>>> - * drm_gem_cma_mmap - memory-map a CMA GEM object
>>>> - * @filp: file object
>>>> - * @vma: VMA for the area to be mapped
>>>> - *
>>>> - * This function implements an augmented version of the GEM DRM file
>>>> mmap
>>>> - * operation for CMA objects: In addition to the usual GEM VMA setup it
>>>> - * immediately faults in the entire object instead of using on-demaind
>>>> - * faulting. Drivers which employ the CMA helpers should use this
>>>> function
>>>> - * as their ->mmap() handler in the DRM device file's file_operations
>>>> - * structure.
>>>> - *
>>>> - * Instead of directly referencing this function, drivers should use
>>>> the
>>>> - * DEFINE_DRM_GEM_CMA_FOPS().macro.
>>>> - *
>>>> - * Returns:
>>>> - * 0 on success or a negative error code on failure.
>>>> - */
>>>> -int drm_gem_cma_mmap(struct file *filp, struct vm_area_struct *vma)
>>>> -{
>>>> -    struct drm_gem_cma_object *cma_obj;
>>>> -    struct drm_gem_object *gem_obj;
>>>> -    int ret;
>>>> -
>>>> -    ret = drm_gem_mmap(filp, vma);
>>>> -    if (ret)
>>>> -        return ret;
>>>> -
>>>> -    gem_obj = vma->vm_private_data;
>>>> -    cma_obj = to_drm_gem_cma_obj(gem_obj);
>>>> -
>>>> -    return drm_gem_cma_mmap_obj(cma_obj, vma);
>>>> -}
>>>> -EXPORT_SYMBOL_GPL(drm_gem_cma_mmap);
>>>> -
>>>>    #ifndef CONFIG_MMU
>>>>    /**
>>>>     * drm_gem_cma_get_unmapped_area - propose address for mapping in
>>>> noMMU cases
>>>> @@ -500,33 +445,6 @@ drm_gem_cma_prime_import_sg_table(struct
>>>> drm_device *dev,
>>>>    }
>>>>    EXPORT_SYMBOL_GPL(drm_gem_cma_prime_import_sg_table);
>>>>    -/**
>>>> - * drm_gem_cma_prime_mmap - memory-map an exported CMA GEM object
>>>> - * @obj: GEM object
>>>> - * @vma: VMA for the area to be mapped
>>>> - *
>>>> - * This function maps a buffer imported via DRM PRIME into a userspace
>>>> - * process's address space. Drivers that use the CMA helpers should
>>>> set this
>>>> - * as their &drm_driver.gem_prime_mmap callback.
>>>> - *
>>>> - * Returns:
>>>> - * 0 on success or a negative error code on failure.
>>>> - */
>>>> -int drm_gem_cma_prime_mmap(struct drm_gem_object *obj,
>>>> -               struct vm_area_struct *vma)
>>>> -{
>>>> -    struct drm_gem_cma_object *cma_obj;
>>>> -    int ret;
>>>> -
>>>> -    ret = drm_gem_mmap_obj(obj, obj->size, vma);
>>>> -    if (ret < 0)
>>>> -        return ret;
>>>> -
>>>> -    cma_obj = to_drm_gem_cma_obj(obj);
>>>> -    return drm_gem_cma_mmap_obj(cma_obj, vma);
>>>> -}
>>>> -EXPORT_SYMBOL_GPL(drm_gem_cma_prime_mmap);
>>>> -
>>>>    /**
>>>>     * drm_gem_cma_vmap - map a CMA GEM object into the kernel's virtual
>>>>     *     address space
>>>> @@ -553,6 +471,43 @@ int drm_gem_cma_vmap(struct drm_gem_object *obj,
>>>> struct dma_buf_map *map)
>>>>    }
>>>>    EXPORT_SYMBOL_GPL(drm_gem_cma_vmap);
>>>>    +/**
>>>> + * drm_gem_cma_mmap - memory-map an exported CMA GEM object
>>>> + * @obj: GEM object
>>>> + * @vma: VMA for the area to be mapped
>>>> + *
>>>> + * This function maps a buffer into a userspace process's address
>>>> space.
>>>> + * In addition to the usual GEM VMA setup it immediately faults in
>>>> the entire
>>>> + * object instead of using on-demand faulting. Drivers that use the CMA
>>>> + * helpers should set this as their &drm_gem_object_funcs.mmap
>>>> callback.
>>>> + *
>>>> + * Returns:
>>>> + * 0 on success or a negative error code on failure.
>>>> + */
>>>> +int drm_gem_cma_mmap(struct drm_gem_object *obj, struct
>>>> vm_area_struct *vma)
>>>> +{
>>>> +    struct drm_gem_cma_object *cma_obj;
>>>> +    int ret;
>>>> +
>>>> +    /*
>>>> +     * Clear the VM_PFNMAP flag that was set by drm_gem_mmap(), and
>>>> set the
>>>> +     * vm_pgoff (used as a fake buffer offset by DRM) to 0 as we
>>>> want to map
>>>> +     * the whole buffer.
>>>> +     */
>>>> +    vma->vm_pgoff -= drm_vma_node_start(&obj->vma_node);
>>>> +    vma->vm_flags &= ~VM_PFNMAP;
>>>> +
>>>> +    cma_obj = to_drm_gem_cma_obj(obj);
>>>> +
>>>> +    ret = dma_mmap_wc(cma_obj->base.dev->dev, vma, cma_obj->vaddr,
>>>> +              cma_obj->paddr, vma->vm_end - vma->vm_start);
>>>> +    if (ret)
>>>> +        drm_gem_vm_close(vma);
>>>> +
>>>> +    return ret;
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(drm_gem_cma_mmap);
>>>> +
>>>>    /**
>>>>     * drm_gem_cma_prime_import_sg_table_vmap - PRIME import another
>>>> driver's
>>>>     *    scatter/gather table and get the virtual address of the buffer
>>>> diff --git a/drivers/gpu/drm/pl111/pl111_drv.c
>>>> b/drivers/gpu/drm/pl111/pl111_drv.c
>>>> index 40e6708fbbe2..e4dcaef6c143 100644
>>>> --- a/drivers/gpu/drm/pl111/pl111_drv.c
>>>> +++ b/drivers/gpu/drm/pl111/pl111_drv.c
>>>> @@ -228,7 +228,7 @@ static const struct drm_driver pl111_drm_driver = {
>>>>        .prime_handle_to_fd = drm_gem_prime_handle_to_fd,
>>>>        .prime_fd_to_handle = drm_gem_prime_fd_to_handle,
>>>>        .gem_prime_import_sg_table = pl111_gem_import_sg_table,
>>>> -    .gem_prime_mmap = drm_gem_cma_prime_mmap,
>>>> +    .gem_prime_mmap = drm_gem_prime_mmap,
>>>>      #if defined(CONFIG_DEBUG_FS)
>>>>        .debugfs_init = pl111_debugfs_init,
>>>> diff --git a/drivers/gpu/drm/vc4/vc4_bo.c b/drivers/gpu/drm/vc4/vc4_bo.c
>>>> index 813e6cb3f9af..dc316cb79e00 100644
>>>> --- a/drivers/gpu/drm/vc4/vc4_bo.c
>>>> +++ b/drivers/gpu/drm/vc4/vc4_bo.c
>>>> @@ -782,7 +782,7 @@ int vc4_prime_mmap(struct drm_gem_object *obj,
>>>> struct vm_area_struct *vma)
>>>>            return -EINVAL;
>>>>        }
>>>>    -    return drm_gem_cma_prime_mmap(obj, vma);
>>>> +    return drm_gem_prime_mmap(obj, vma);
>>>>    }
>>>>      int vc4_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map
>>>> *map)
>>>> diff --git a/include/drm/drm_gem_cma_helper.h
>>>> b/include/drm/drm_gem_cma_helper.h
>>>> index 4680275ab339..0a9711caa3e8 100644
>>>> --- a/include/drm/drm_gem_cma_helper.h
>>>> +++ b/include/drm/drm_gem_cma_helper.h
>>>> @@ -59,7 +59,7 @@ struct drm_gem_cma_object {
>>>>            .poll        = drm_poll,\
>>>>            .read        = drm_read,\
>>>>            .llseek        = noop_llseek,\
>>>> -        .mmap        = drm_gem_cma_mmap,\
>>>> +        .mmap        = drm_gem_mmap,\
>>>>            DRM_GEM_CMA_UNMAPPED_AREA_FOPS \
>>>>        }
>>>>    @@ -76,9 +76,6 @@ int drm_gem_cma_dumb_create(struct drm_file
>>>> *file_priv,
>>>>                    struct drm_device *drm,
>>>>                    struct drm_mode_create_dumb *args);
>>>>    -/* set vm_flags and we can change the VM attribute to other one at
>>>> here */
>>>> -int drm_gem_cma_mmap(struct file *filp, struct vm_area_struct *vma);
>>>> -
>>>>    /* allocate physical memory */
>>>>    struct drm_gem_cma_object *drm_gem_cma_create(struct drm_device *drm,
>>>>                              size_t size);
>>>> @@ -101,9 +98,8 @@ struct drm_gem_object *
>>>>    drm_gem_cma_prime_import_sg_table(struct drm_device *dev,
>>>>                      struct dma_buf_attachment *attach,
>>>>                      struct sg_table *sgt);
>>>> -int drm_gem_cma_prime_mmap(struct drm_gem_object *obj,
>>>> -               struct vm_area_struct *vma);
>>>>    int drm_gem_cma_vmap(struct drm_gem_object *obj, struct dma_buf_map
>>>> *map);
>>>> +int drm_gem_cma_mmap(struct drm_gem_object *obj, struct
>>>> vm_area_struct *vma);
>>>>      /**
>>>>     * DRM_GEM_CMA_DRIVER_OPS_WITH_DUMB_CREATE - CMA GEM driver operations
>>>> @@ -123,7 +119,7 @@ int drm_gem_cma_vmap(struct drm_gem_object *obj,
>>>> struct dma_buf_map *map);
>>>>        .prime_handle_to_fd    = drm_gem_prime_handle_to_fd, \
>>>>        .prime_fd_to_handle    = drm_gem_prime_fd_to_handle, \
>>>>        .gem_prime_import_sg_table = drm_gem_cma_prime_import_sg_table, \
>>>> -    .gem_prime_mmap        = drm_gem_cma_prime_mmap
>>>> +    .gem_prime_mmap        = drm_gem_prime_mmap
>>>>      /**
>>>>     * DRM_GEM_CMA_DRIVER_OPS - CMA GEM driver operations
>>>>
>>>
>>> _______________________________________________
>>> dri-devel mailing list
>>> dri-devel@lists.freedesktop.org
>>> https://lists.freedesktop.org/mailman/listinfo/dri-devel
>>>
>>
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer


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Re: [PATCH 2/2] drm/cma-helper: Implement mmap as GEM CMA object functions

[Kieran Bingham]

Hi Thomas,

On 14/01/2021 15:15, Thomas Zimmermann wrote:
>>>> On 23/11/2020 11:56, Thomas Zimmermann wrote:
>>>>> The new GEM object function drm_gem_cma_mmap() sets the VMA flags
>>>>> and offset as in the old implementation and immediately maps in the
>>>>> buffer's memory pages.
>>>>>
>>>>> Changing CMA helpers to use the GEM object function allows for the
>>>>> removal of the special implementations for mmap and gem_prime_mmap
>>>>> callbacks. The regular functions drm_gem_mmap() and
>>>>> drm_gem_prime_mmap()
>>>>> are now used.
>>>>
>>>> I've encountered a memory leak regression in our Renesas R-Car DU
>>>> tests,
>>>> and git bisection has led me to this patch (as commit f5ca8eb6f9).
>>>>
>>>> Running the tests sequentially, while grepping /proc/meminfo for
>>>> Cma, it
>>>> is evident that CMA memory is not released, until exhausted and the
>>>> allocations fail (seen in [0]) shown by the error report:
>>>>
>>>>>       self.fbs.append(pykms.DumbFramebuffer(self.card, mode.hdisplay,
>>>>> mode.vdisplay, "XR24"))
>>>>> ValueError: DRM_IOCTL_MODE_CREATE_DUMB failed: Cannot allocate memory
>>>>
>>>>
>>>> Failing tests at f5ca8eb6f9 can be seen at [0], while the tests pass
>>>> successfully [1] on the commit previous to that (bc2532ab7c2):
>>>>
>>>> Reverting f5ca8eb6f9 also produces a successful pass [2]
>>>>
>>>>    [0] https://paste.ubuntu.com/p/VjPGPgswxR/ # Failed at f5ca8eb6f9
>>>>    [1] https://paste.ubuntu.com/p/78RRp2WpNR/ # Success at bc2532ab7c2
>>>>    [2] https://paste.ubuntu.com/p/qJKjZZN2pt/ # Success with revert
>>>>
>>>>
>>>> I don't believe we handle mmap specially in the RCar-DU driver, so I
>>>> wonder if this issue has hit anyone else as well?
>>>>
>>>> Any ideas of a repair without a revert ? Or do we just need to submit a
>>>> revert?
>>>
>>> I think we might not be setting the VMA ops and therefore not finalize
>>> the BO correctly. Could you please apply the attched (quick-and-dirty)
>>> patch and try again?
>>
>> Thanks for the quick response.
>>
>> I can confirm the quick-and-dirty patch resolves the issue:
>>    https://paste.ubuntu.com/p/sKDp3dNvwV/
>>
>> You can add a
>> Tested-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
> 
> Great! If you don't mind, I'd also add you in the Reported-by tag.

Certainly!

>>
>> if it stays like that, but I suspect there might be a better place to
>> initialise the ops rather than in the mmap call itself.
> 
> I think that's the fix, basically. We could put such a line as a
> fall-back somewhere into the DRM core code. But I don't know if this
> really works with all drivers. Maybe there's one that requires vm_ops to
> be NULL.

Ok, that's reaching beyond code I've explored, so I'll leave it to you.


> Thanks for reporting this issue and testing quickly.

Thanks for fixing so quickly :-)

Regards

Kieran

Re: [PATCH 2/2] drm/cma-helper: Implement mmap as GEM CMA object functions

[Thomas Zimmermann]

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Hi

Am 14.01.21 um 17:28 schrieb Kieran Bingham:
> Hi Thomas,
> 
> On 14/01/2021 15:15, Thomas Zimmermann wrote:
>>>>> On 23/11/2020 11:56, Thomas Zimmermann wrote:
>>>>>> The new GEM object function drm_gem_cma_mmap() sets the VMA flags
>>>>>> and offset as in the old implementation and immediately maps in the
>>>>>> buffer's memory pages.
>>>>>>
>>>>>> Changing CMA helpers to use the GEM object function allows for the
>>>>>> removal of the special implementations for mmap and gem_prime_mmap
>>>>>> callbacks. The regular functions drm_gem_mmap() and
>>>>>> drm_gem_prime_mmap()
>>>>>> are now used.
>>>>>
>>>>> I've encountered a memory leak regression in our Renesas R-Car DU
>>>>> tests,
>>>>> and git bisection has led me to this patch (as commit f5ca8eb6f9).
>>>>>
>>>>> Running the tests sequentially, while grepping /proc/meminfo for
>>>>> Cma, it
>>>>> is evident that CMA memory is not released, until exhausted and the
>>>>> allocations fail (seen in [0]) shown by the error report:
>>>>>
>>>>>>        self.fbs.append(pykms.DumbFramebuffer(self.card, mode.hdisplay,
>>>>>> mode.vdisplay, "XR24"))
>>>>>> ValueError: DRM_IOCTL_MODE_CREATE_DUMB failed: Cannot allocate memory
>>>>>
>>>>>
>>>>> Failing tests at f5ca8eb6f9 can be seen at [0], while the tests pass
>>>>> successfully [1] on the commit previous to that (bc2532ab7c2):
>>>>>
>>>>> Reverting f5ca8eb6f9 also produces a successful pass [2]
>>>>>
>>>>>     [0] https://paste.ubuntu.com/p/VjPGPgswxR/ # Failed at f5ca8eb6f9
>>>>>     [1] https://paste.ubuntu.com/p/78RRp2WpNR/ # Success at bc2532ab7c2
>>>>>     [2] https://paste.ubuntu.com/p/qJKjZZN2pt/ # Success with revert
>>>>>
>>>>>
>>>>> I don't believe we handle mmap specially in the RCar-DU driver, so I
>>>>> wonder if this issue has hit anyone else as well?
>>>>>
>>>>> Any ideas of a repair without a revert ? Or do we just need to submit a
>>>>> revert?
>>>>
>>>> I think we might not be setting the VMA ops and therefore not finalize
>>>> the BO correctly. Could you please apply the attched (quick-and-dirty)
>>>> patch and try again?
>>>
>>> Thanks for the quick response.
>>>
>>> I can confirm the quick-and-dirty patch resolves the issue:
>>>     https://paste.ubuntu.com/p/sKDp3dNvwV/
>>>
>>> You can add a
>>> Tested-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
>>
>> Great! If you don't mind, I'd also add you in the Reported-by tag.
> 
> Certainly!
> 
>>>
>>> if it stays like that, but I suspect there might be a better place to
>>> initialise the ops rather than in the mmap call itself.
>>
>> I think that's the fix, basically. We could put such a line as a
>> fall-back somewhere into the DRM core code. But I don't know if this
>> really works with all drivers. Maybe there's one that requires vm_ops to
>> be NULL.
> 
> Ok, that's reaching beyond code I've explored, so I'll leave it to you.

Daniel asked for a fix in the DRM core, so I'll go with the alternative 
approach. If you have the time, I'd appreciate another test run.

Best regards
Thomas

> 
> 
>> Thanks for reporting this issue and testing quickly.
> 
> Thanks for fixing so quickly :-)
> 
> Regards
> 
> Kieran
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer


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Re: [PATCH 2/2] drm/cma-helper: Implement mmap as GEM CMA object functions

[Daniel Vetter]

On Thu, Jan 14, 2021 at 02:26:41PM +0100, Thomas Zimmermann wrote:
> From d0583fe22cd0cd29749ff679e46e13b58de325cb Mon Sep 17 00:00:00 2001
> From: Thomas Zimmermann <tzimmermann@suse.de>
> Date: Thu, 14 Jan 2021 14:21:51 +0100
> Subject: [PATCH] drm/cma: Set vma ops in mmap function
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---
>  drivers/gpu/drm/drm_gem_cma_helper.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c b/drivers/gpu/drm/drm_gem_cma_helper.c
> index 7942cf05cd93..0bd192736169 100644
> --- a/drivers/gpu/drm/drm_gem_cma_helper.c
> +++ b/drivers/gpu/drm/drm_gem_cma_helper.c
> @@ -489,6 +489,8 @@ int drm_gem_cma_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
>  	struct drm_gem_cma_object *cma_obj;
>  	int ret;
>  
> +	vma->vm_ops = obj->funcs->vm_ops;

I think this should be done in core, otherwise we have tons of refcount
leaks. I think this was an oversight when we've done that refactoring.

Also drivers can easily overwrite this one if they really have to, but not
assigned this is a clear bug.
-Daniel

> +
>  	/*
>  	 * Clear the VM_PFNMAP flag that was set by drm_gem_mmap(), and set the
>  	 * vm_pgoff (used as a fake buffer offset by DRM) to 0 as we want to map
> -- 
> 2.29.2
> 


-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch