[PATCH 1/1] drm/mm/selftests: fix wrong return type casting

[Christian König]

Am 22.06.20 um 15:45 schrieb Nirmoy Das:
> Function prepare_igt_frag() and get_insert_time() were casting
> signed value to unsigned value before returning error.
> So error check in igt_frag() would not work with unsigned
> return value from get_insert_time() compared against negative
> value.
>
> Addresses-Coverity: ("Unsigned compared against 0, no effect")
> Signed-off-by: Nirmoy Das <nirmoy.das at amd.com>
> Reported-by: Colin Ian King <colin.king at canonical.com>

Reviewed-by: Christian König <christian.koenig at amd.com>

> ---
>   drivers/gpu/drm/selftests/test-drm_mm.c | 21 +++++++--------------
>   1 file changed, 7 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/gpu/drm/selftests/test-drm_mm.c b/drivers/gpu/drm/selftests/test-drm_mm.c
> index 3846b0f5bae3..3306d8bd0544 100644
> --- a/drivers/gpu/drm/selftests/test-drm_mm.c
> +++ b/drivers/gpu/drm/selftests/test-drm_mm.c
> @@ -1041,13 +1041,12 @@ static int prepare_igt_frag(struct drm_mm *mm,
>   {
>   	unsigned int size = 4096;
>   	unsigned int i;
> -	u64 ret = -EINVAL;
>
>   	for (i = 0; i < num_insert; i++) {
>   		if (!expect_insert(mm, &nodes[i], size, 0, i,
>   				   mode) != 0) {
>   			pr_err("%s insert failed\n", mode->name);
> -			goto out;
> +			return -EINVAL;
>   		}
>   	}
>
> @@ -1057,8 +1056,7 @@ static int prepare_igt_frag(struct drm_mm *mm,
>   			drm_mm_remove_node(&nodes[i]);
>   	}
>
> -out:
> -	return ret;
> +	return 0;
>
>   }
>
> @@ -1070,21 +1068,16 @@ static u64 get_insert_time(struct drm_mm *mm,
>   	unsigned int size = 8192;
>   	ktime_t start;
>   	unsigned int i;
> -	u64 ret = -EINVAL;
>
>   	start = ktime_get();
>   	for (i = 0; i < num_insert; i++) {
>   		if (!expect_insert(mm, &nodes[i], size, 0, i, mode) != 0) {
>   			pr_err("%s insert failed\n", mode->name);
> -			goto out;
> +			return 0;
>   		}
>   	}
>
> -	ret = ktime_to_ns(ktime_sub(ktime_get(), start));
> -
> -out:
> -	return ret;
> -
> +	return ktime_to_ns(ktime_sub(ktime_get(), start));
>   }
>
>   static int igt_frag(void *ignored)
> @@ -1119,17 +1112,17 @@ static int igt_frag(void *ignored)
>   			continue;
>
>   		ret = prepare_igt_frag(&mm, nodes, insert_size, mode);
> -		if (!ret)
> +		if (ret)
>   			goto err;
>
>   		insert_time1 = get_insert_time(&mm, insert_size,
>   					       nodes + insert_size, mode);
> -		if (insert_time1 < 0)
> +		if (insert_time1 == 0)
>   			goto err;
>
>   		insert_time2 = get_insert_time(&mm, (insert_size * 2),
>   					       nodes + insert_size * 2, mode);
> -		if (insert_time2 < 0)
> +		if (insert_time2 == 0)
>   			goto err;
>
>   		pr_info("%s fragmented insert of %u and %u insertions took %llu and %llu nsecs\n",
> --
> 2.27.0
>