drm/amd/display: Add KUnit test for wb jobs

[WHAT]
Add KUnit tests to verify both functions return early when
job->fb is NULL without touching any buffer object.

Assisted-by: Copilot:Claude-Opus-4.6
Reviewed-by: Bhawanpreet Lakha <bhawanpreet.lakha@amd.com>
Signed-off-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: George Zhang <george.zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_wb.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_wb.c
index 0bf82e4..1fbb568 100644 (file)
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_wb.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_wb.c
@@ -85,7 +85,7 @@ STATIC_IFN_KUNIT int amdgpu_dm_wb_connector_get_modes(struct drm_connector *conn
 }
 EXPORT_IF_KUNIT(amdgpu_dm_wb_connector_get_modes);
 
-static int amdgpu_dm_wb_prepare_job(struct drm_writeback_connector *wb_connector,
+STATIC_IFN_KUNIT int amdgpu_dm_wb_prepare_job(struct drm_writeback_connector *wb_connector,
                               struct drm_writeback_job *job)
 {
        struct amdgpu_framebuffer *afb;
@@ -146,8 +146,9 @@ error_unlock:
        amdgpu_bo_unreserve(rbo);
        return r;
 }
+EXPORT_IF_KUNIT(amdgpu_dm_wb_prepare_job);
 
-static void amdgpu_dm_wb_cleanup_job(struct drm_writeback_connector *connector,
+STATIC_IFN_KUNIT void amdgpu_dm_wb_cleanup_job(struct drm_writeback_connector *connector,
                                struct drm_writeback_job *job)
 {
        struct amdgpu_bo *rbo;
@@ -167,6 +168,7 @@ static void amdgpu_dm_wb_cleanup_job(struct drm_writeback_connector *connector,
        amdgpu_bo_unreserve(rbo);
        amdgpu_bo_unref(&rbo);
 }
+EXPORT_IF_KUNIT(amdgpu_dm_wb_cleanup_job);
 
 static const struct drm_encoder_helper_funcs amdgpu_dm_wb_encoder_helper_funcs = {
        .atomic_check = amdgpu_dm_wb_encoder_atomic_check,

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_wb.h b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_wb.h
index 7e9fd7a..5fd616b 100644 (file)
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_wb.h
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_wb.h
@@ -44,6 +44,10 @@ int amdgpu_dm_wb_encoder_atomic_check(struct drm_encoder *encoder,
                                      struct drm_crtc_state *crtc_state,
                                      struct drm_connector_state *conn_state);
 int amdgpu_dm_wb_connector_get_modes(struct drm_connector *connector);
+int amdgpu_dm_wb_prepare_job(struct drm_writeback_connector *wb_connector,
+                            struct drm_writeback_job *job);
+void amdgpu_dm_wb_cleanup_job(struct drm_writeback_connector *connector,
+                             struct drm_writeback_job *job);
 #endif
 
 #endif

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_wb_test.c b/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_wb_test.c
index c71f61a..b43bc24 100644 (file)
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_wb_test.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_wb_test.c
@@ -364,6 +364,47 @@ static void dm_test_wb_connector_init_success(struct kunit *test)
        KUNIT_EXPECT_EQ(test, wbcon->base.encoder.possible_crtcs, 0x1);
 }
 
+/* Tests for amdgpu_dm_wb_prepare_job / amdgpu_dm_wb_cleanup_job */
+
+/**
+ * dm_test_wb_prepare_job_no_fb - Verify prepare_job early return without a framebuffer
+ * @test: KUnit test context
+ *
+ * When job->fb is NULL there is nothing to pin, so amdgpu_dm_wb_prepare_job()
+ * must return 0 without touching any buffer object.
+ */
+static void dm_test_wb_prepare_job_no_fb(struct kunit *test)
+{
+       struct drm_writeback_job *job;
+       int ret;
+
+       job = kunit_kzalloc(test, sizeof(*job), GFP_KERNEL);
+       KUNIT_ASSERT_NOT_NULL(test, job);
+
+       job->fb = NULL;
+       ret = amdgpu_dm_wb_prepare_job(NULL, job);
+       KUNIT_EXPECT_EQ(test, ret, 0);
+}
+
+/**
+ * dm_test_wb_cleanup_job_no_fb - Verify cleanup_job early return without a framebuffer
+ * @test: KUnit test context
+ *
+ * When job->fb is NULL there is nothing to unpin, so amdgpu_dm_wb_cleanup_job()
+ * must return immediately.
+ */
+static void dm_test_wb_cleanup_job_no_fb(struct kunit *test)
+{
+       struct drm_writeback_job *job;
+
+       job = kunit_kzalloc(test, sizeof(*job), GFP_KERNEL);
+       KUNIT_ASSERT_NOT_NULL(test, job);
+
+       job->fb = NULL;
+       /* Should return without dereferencing any buffer object. */
+       amdgpu_dm_wb_cleanup_job(NULL, job);
+}
+
 static struct kunit_case dm_wb_test_cases[] = {
        /* amdgpu_dm_wb_encoder_atomic_check */
        KUNIT_CASE(dm_test_wb_atomic_check_no_job),
@@ -378,6 +419,9 @@ static struct kunit_case dm_wb_test_cases[] = {
        KUNIT_CASE(dm_test_wb_get_modes_bounded_by_max),
        /* amdgpu_dm_wb_connector_init */
        KUNIT_CASE(dm_test_wb_connector_init_success),
+       /* amdgpu_dm_wb_prepare_job / amdgpu_dm_wb_cleanup_job */
+       KUNIT_CASE(dm_test_wb_prepare_job_no_fb),
+       KUNIT_CASE(dm_test_wb_cleanup_job_no_fb),
        {}
 };