Re: [PATCH v2] drm/gem: fix mmap vma size calculations

[Daniel Vetter <daniel@ffwll.ch>]

On Fri, Jul 26, 2013 at 12:09:32PM +0200, David Herrmann wrote:
> The VMA manager is page-size based so drm_vma_node_size() returns the size
> in pages. However, drm_gem_mmap_obj() requires the size in bytes. Apply
> PAGE_SHIFT so we no longer get EINVAL during mmaps due to too small
> buffers.
> 
> This bug was introduced in commit:
>   0de23977cfeb5b357ec884ba15417ae118ff9e9b
>   "drm/gem: convert to new unified vma manager"
> 
> Fixes i915 gtt mmap failure reported by Sedat Dilek in:
>   Re: linux-next: Tree for Jul 25 [ call-trace: drm | drm-intel related? ]
> 
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
> Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
> Tested-by: Sedat Dilek <sedat.dilek@gmail.com>

I remember that I even checked whether v4 was consistent with pages vs.
bytes ;-) So

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

on this little fixup.
-Daniel

> ---
>  drivers/gpu/drm/drm_gem.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
> index 3613b50..1f76572 100644
> --- a/drivers/gpu/drm/drm_gem.c
> +++ b/drivers/gpu/drm/drm_gem.c
> @@ -666,7 +666,7 @@ int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
>  	}
>  
>  	obj = container_of(node, struct drm_gem_object, vma_node);
> -	ret = drm_gem_mmap_obj(obj, drm_vma_node_size(node), vma);
> +	ret = drm_gem_mmap_obj(obj, drm_vma_node_size(node) << PAGE_SHIFT, vma);
>  
>  	mutex_unlock(&dev->struct_mutex);
>  
> -- 
> 1.8.3.4
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch