[PATCH] drm/v3d: fix copy_from_user() error codes

[Melissa Wen]

On 10/11, Dan Carpenter wrote:
> The copy_to/from_user() function returns the number of bytes remaining
> to be copied, but we want to return -EFAULT on error.
> 
> Fixes: e4165ae8304e ("drm/v3d: add multiple syncobjs support")
> Signed-off-by: Dan Carpenter <dan.carpenter at oracle.com>
> ---
>  drivers/gpu/drm/v3d/v3d_gem.c | 13 ++++++-------
>  1 file changed, 6 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/v3d/v3d_gem.c b/drivers/gpu/drm/v3d/v3d_gem.c
> index 6a000d77c568..e47ae40a865a 100644
> --- a/drivers/gpu/drm/v3d/v3d_gem.c
> +++ b/drivers/gpu/drm/v3d/v3d_gem.c
> @@ -487,8 +487,8 @@ v3d_job_init(struct v3d_dev *v3d, struct drm_file *file_priv,
>  			for (i = 0; i < se->in_sync_count; i++) {
>  				struct drm_v3d_sem in;
>  
> -				ret = copy_from_user(&in, handle++, sizeof(in));
> -				if (ret) {
> +				if (copy_from_user(&in, handle++, sizeof(in))) {
> +					ret = -EFAULT;
>  					DRM_DEBUG("Failed to copy wait dep handle.\n");
>  					goto fail_deps;
>  				}
> @@ -609,8 +609,8 @@ v3d_get_multisync_post_deps(struct drm_file *file_priv,
>  	for (i = 0; i < count; i++) {
>  		struct drm_v3d_sem out;
>  
> -		ret = copy_from_user(&out, post_deps++, sizeof(out));
> -		if (ret) {
> +		if (copy_from_user(&out, post_deps++, sizeof(out))) {
> +			ret = -EFAULT;
>  			DRM_DEBUG("Failed to copy post dep handles\n");
>  			goto fail;
>  		}
> @@ -646,9 +646,8 @@ v3d_get_multisync_submit_deps(struct drm_file *file_priv,
>  	struct v3d_submit_ext *se = data;
>  	int ret;
>  
> -	ret = copy_from_user(&multisync, ext, sizeof(multisync));
> -	if (ret)
> -		return ret;
> +	if (copy_from_user(&multisync, ext, sizeof(multisync)))
> +		return -EFAULT;
>  
>  	if (multisync.pad)
>  		return -EINVAL;
Hi Dan,

Thanks for catching this.

Reviewed-by: Melissa Wen <mwen at igalia.com>
> -- 
> 2.20.1
> 
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