Re: [Intel-gfx] [RFC v4 03/14] drm/i915/vm_bind: Expose i915_gem_object_max_page_size()

[Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>]

On 21/09/2022 08:09, Niranjana Vishwanathapura wrote:
> Expose i915_gem_object_max_page_size() function non-static
> which will be used by the vm_bind feature.
> 
> Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>
> Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
> ---
>   drivers/gpu/drm/i915/gem/i915_gem_create.c | 20 +++++++++++++++-----
>   drivers/gpu/drm/i915/gem/i915_gem_object.h |  2 ++
>   2 files changed, 17 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_create.c b/drivers/gpu/drm/i915/gem/i915_gem_create.c
> index 33673fe7ee0a..3b3ab4abb0a3 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_create.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_create.c
> @@ -11,14 +11,24 @@
>   #include "pxp/intel_pxp.h"
>   
>   #include "i915_drv.h"
> +#include "i915_gem_context.h"

I can't spot that you are adding any code which would need this? 
I915_GTT_PAGE_SIZE_4K? It is in intel_gtt.h.

>   #include "i915_gem_create.h"
>   #include "i915_trace.h"
>   #include "i915_user_extensions.h"
>   
> -static u32 object_max_page_size(struct intel_memory_region **placements,
> -				unsigned int n_placements)
> +/**
> + * i915_gem_object_max_page_size() - max of min_page_size of the regions
> + * @placements:  list of regions
> + * @n_placements: number of the placements
> + *
> + * Calculates the max of the min_page_size of a list of placements passed in.
> + *
> + * Return: max of the min_page_size
> + */
> +u32 i915_gem_object_max_page_size(struct intel_memory_region **placements,
> +				  unsigned int n_placements)
>   {
> -	u32 max_page_size = 0;
> +	u32 max_page_size = I915_GTT_PAGE_SIZE_4K;
>   	int i;
>   
>   	for (i = 0; i < n_placements; i++) {
> @@ -28,7 +38,6 @@ static u32 object_max_page_size(struct intel_memory_region **placements,
>   		max_page_size = max_t(u32, max_page_size, mr->min_page_size);
>   	}
>   
> -	GEM_BUG_ON(!max_page_size);
>   	return max_page_size;
>   }
>   
> @@ -99,7 +108,8 @@ __i915_gem_object_create_user_ext(struct drm_i915_private *i915, u64 size,
>   
>   	i915_gem_flush_free_objects(i915);
>   
> -	size = round_up(size, object_max_page_size(placements, n_placements));
> +	size = round_up(size, i915_gem_object_max_page_size(placements,
> +							    n_placements));
>   	if (size == 0)
>   		return ERR_PTR(-EINVAL);

Because of the changes above this path is now unreachable. I suppose it 
was meant to tell the user "you have supplied no placements"? But then 
GEM_BUG_ON (which you remove) used to be wrong.

Regards,

Tvrtko

>   
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h
> index 7317d4102955..8c97bddad921 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
> @@ -47,6 +47,8 @@ static inline bool i915_gem_object_size_2big(u64 size)
>   }
>   
>   void i915_gem_init__objects(struct drm_i915_private *i915);
> +u32 i915_gem_object_max_page_size(struct intel_memory_region **placements,
> +				  unsigned int n_placements);
>   
>   void i915_objects_module_exit(void);
>   int i915_objects_module_init(void);