Re: [PATCH 3/5] drm/msm: use the right pgprot when mapping BOs in the kernel

[Jordan Crouse]

On Fri, Apr 23, 2021 at 03:08:19PM -0400, Jonathan Marek wrote:
> Use the same logic as the userspace mapping.
> 
> This fixes msm_rd with cached BOs.
> 

Acked-by: Jordan Crouse <jordan@xxxxxxxxxxxxxxxxx>

> Signed-off-by: Jonathan Marek <jonathan@xxxxxxxx>
> ---
>  drivers/gpu/drm/msm/msm_gem.c | 19 +++++++++++--------
>  1 file changed, 11 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
> index 09abda42d764..0f58937be0a9 100644
> --- a/drivers/gpu/drm/msm/msm_gem.c
> +++ b/drivers/gpu/drm/msm/msm_gem.c
> @@ -199,6 +199,15 @@ void msm_gem_put_pages(struct drm_gem_object *obj)
>  	/* when we start tracking the pin count, then do something here */
>  }
>  
> +static pgprot_t msm_gem_pgprot(struct msm_gem_object *msm_obj, pgprot_t prot)
> +{
> +	if (msm_obj->flags & MSM_BO_WC)
> +		return pgprot_writecombine(prot);
> +	if (msm_obj->flags & MSM_BO_UNCACHED)
> +		return pgprot_noncached(prot);
> +	return prot;
> +}
> +
>  int msm_gem_mmap_obj(struct drm_gem_object *obj,
>  		struct vm_area_struct *vma)
>  {
> @@ -206,13 +215,7 @@ int msm_gem_mmap_obj(struct drm_gem_object *obj,
>  
>  	vma->vm_flags &= ~VM_PFNMAP;
>  	vma->vm_flags |= VM_MIXEDMAP;
> -
> -	if (msm_obj->flags & MSM_BO_WC)
> -		vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
> -	else if (msm_obj->flags & MSM_BO_UNCACHED)
> -		vma->vm_page_prot = pgprot_noncached(vm_get_page_prot(vma->vm_flags));
> -	else
> -		vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
> +	vma->vm_page_prot = msm_gem_pgprot(msm_obj, vm_get_page_prot(vma->vm_flags));
>  
>  	return 0;
>  }
> @@ -632,7 +635,7 @@ static void *get_vaddr(struct drm_gem_object *obj, unsigned madv)
>  			goto fail;
>  		}
>  		msm_obj->vaddr = vmap(pages, obj->size >> PAGE_SHIFT,
> -				VM_MAP, pgprot_writecombine(PAGE_KERNEL));
> +				VM_MAP, msm_gem_pgprot(msm_obj, PAGE_KERNEL));
>  		if (msm_obj->vaddr == NULL) {
>  			ret = -ENOMEM;
>  			goto fail;
> -- 
> 2.26.1
>