Re: [PATCH] drm/i915: fix up error cleanup in i915_gem_object_bind_to_gtt

[Ben Widawsky <ben@bwidawsk.net>]

On Mon, Jul 22, 2013 at 12:12:38PM +0200, Daniel Vetter wrote:
> This has been broken in
> 
> commit 2f63315692b1d3c055972ad33fc7168ae908b97b
> Author: Ben Widawsky <ben@bwidawsk.net>
> Date:   Wed Jul 17 12:19:03 2013 -0700
> 
>     drm/i915: Create VMAs
> 
> which resulted in an OOPS the first time around we've hit -ENOSPC.
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=67156
> Cc: Imre Deak <imre.deak@intel.com>
> Cc: Ben Widawsky <ben@bwidawsk.net>
> Tested-by: meng <mengmeng.meng@intel.com>
> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> ---
>  drivers/gpu/drm/i915/i915_gem.c | 14 ++++++++------
>  1 file changed, 8 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index cfa6588..c87a6ec 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -3121,8 +3121,8 @@ i915_gem_object_bind_to_gtt(struct drm_i915_gem_object *obj,
>  
>  	vma = i915_gem_vma_create(obj, &dev_priv->gtt.base);
>  	if (IS_ERR(vma)) {
> -		i915_gem_object_unpin_pages(obj);
> -		return PTR_ERR(vma);
> +		ret = PTR_ERR(vma);
> +		goto err_unpin;
>  	}

Adding the extra goto here seems pointless to me.

>  
>  search_free:
> @@ -3138,17 +3138,17 @@ search_free:
>  		if (ret == 0)
>  			goto search_free;
>  
> -		goto err_out;
> +		goto err_free_vma;
>  	}

My preference would be to exit early in drm_mm_remove_node() if the node
isn't allocated. I think at least we should add a WARN to
drm_mm_remove_node if the node->allocated == 0.

>  	if (WARN_ON(!i915_gem_valid_gtt_space(dev, &vma->node,
>  					      obj->cache_level))) {
>  		ret = -EINVAL;
> -		goto err_out;
> +		goto err_remove_node;
>  	}
>  
>  	ret = i915_gem_gtt_prepare_object(obj);
>  	if (ret)
> -		goto err_out;
> +		goto err_remove_node;
>  
>  	list_move_tail(&obj->global_list, &dev_priv->mm.bound_list);
>  	list_add_tail(&obj->mm_list, &vm->inactive_list);
> @@ -3167,9 +3167,11 @@ search_free:
>  	i915_gem_verify_gtt(dev);
>  	return 0;
>  
> -err_out:
> +err_remove_node:
>  	drm_mm_remove_node(&vma->node);
> +err_free_vma:
>  	i915_gem_vma_destroy(vma);
> +err_unpin:
>  	i915_gem_object_unpin_pages(obj);
>  	return ret;
>  }

Reviewed-by: Ben Widawsky <ben@bwidawsk.net>

-- 
Ben Widawsky, Intel Open Source Technology Center