[Intel-gfx] [PATCH v2] drm/i915/query: Split out query item checks

[Tvrtko Ursulin]

On 16/01/2019 08:59, Abdiel Janulgue wrote:
> This simplifies adding new query item objects.
> 
> v2: Use query_hdr (Tvrtko, Chris).
>      int instead of u32 in return (Tvrtko)
> 
> Signed-off-by: Abdiel Janulgue <abdiel.janulgue at linux.intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> ---
>   drivers/gpu/drm/i915/i915_query.c | 39 ++++++++++++++++++++-----------
>   1 file changed, 26 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_query.c b/drivers/gpu/drm/i915/i915_query.c
> index cbcb957b7141..b2449cffda51 100644
> --- a/drivers/gpu/drm/i915/i915_query.c
> +++ b/drivers/gpu/drm/i915/i915_query.c
> @@ -10,12 +10,34 @@
>   #include "i915_query.h"
>   #include <uapi/drm/i915_drm.h>
>   
> +static int init_query_item_check(void *query_hdr, size_t data_sz,

AFAIR I think we talked about renaming both header related fields, so 
query_hdr and query_sz, no?

The rest looks good to me.

Although now I am also thinking about how descriptive 
"init_query_item_check" is.. so am tempted to suggest some more obvious 
name for it, maybe even shorter. :) copy_query_item?

Regards,

Tvrtko

> +				 u32 total_length,
> +				 struct drm_i915_query_item *query_item)
> +{
> +	if (query_item->length == 0)
> +		return total_length;
> +
> +	if (query_item->length < total_length)
> +		return -EINVAL;
> +
> +	if (copy_from_user(query_hdr, u64_to_user_ptr(query_item->data_ptr),
> +			   data_sz))
> +		return -EFAULT;
> +
> +	if (!access_ok(u64_to_user_ptr(query_item->data_ptr),
> +		       total_length))
> +		return -EFAULT;
> +
> +	return 0;
> +}
> +
>   static int query_topology_info(struct drm_i915_private *dev_priv,
>   			       struct drm_i915_query_item *query_item)
>   {
>   	const struct sseu_dev_info *sseu = &RUNTIME_INFO(dev_priv)->sseu;
>   	struct drm_i915_query_topology_info topo;
>   	u32 slice_length, subslice_length, eu_length, total_length;
> +	int ret;
>   
>   	if (query_item->flags != 0)
>   		return -EINVAL;
> @@ -33,23 +55,14 @@ static int query_topology_info(struct drm_i915_private *dev_priv,
>   
>   	total_length = sizeof(topo) + slice_length + subslice_length + eu_length;
>   
> -	if (query_item->length == 0)
> -		return total_length;
> -
> -	if (query_item->length < total_length)
> -		return -EINVAL;
> -
> -	if (copy_from_user(&topo, u64_to_user_ptr(query_item->data_ptr),
> -			   sizeof(topo)))
> -		return -EFAULT;
> +	ret = init_query_item_check(&topo, sizeof(topo), total_length,
> +				    query_item);
> +	if (ret != 0)
> +		return ret;
>   
>   	if (topo.flags != 0)
>   		return -EINVAL;
>   
> -	if (!access_ok(u64_to_user_ptr(query_item->data_ptr),
> -		       total_length))
> -		return -EFAULT;
> -
>   	memset(&topo, 0, sizeof(topo));
>   	topo.max_slices = sseu->max_slices;
>   	topo.max_subslices = sseu->max_subslices;
>