Re: [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....@amd.com>
Reported-by: Colin Ian King <colin.k...@canonical.com>

Reviewed-by: Christian König <christian.koe...@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

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