drm/msm/dpu: use drmm-managed allocation for dpu_encoder_virt

It is incorrect to use devm-managed memory allocations for DRM data
structures exposed to userspace. They should use drmm_ allocations.
Change struct dpu_encoder allocation to use drmm_encoder_alloc(). This
removes the need to perform any actions on encoder destruction.
Reviewed-by: Jessica Zhang <quic_jesszhan@quicinc.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/570053/
Link: https://lore.kernel.org/r/20231201211845.1026967-14-dmitry.baryshkov@linaro.org

drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c

@@ -442,23 +442,6 @@ int dpu_encoder_get_linecount(struct drm_encoder *drm_enc)
 	return linecount;
 }
 
-static void dpu_encoder_destroy(struct drm_encoder *drm_enc)
-{
-	struct dpu_encoder_virt *dpu_enc = NULL;
-	int i = 0;
-
-	if (!drm_enc) {
-		DPU_ERROR("invalid encoder\n");
-		return;
-	}
-
-	dpu_enc = to_dpu_encoder_virt(drm_enc);
-	DPU_DEBUG_ENC(dpu_enc, "\n");
-
-	drm_encoder_cleanup(drm_enc);
-	mutex_destroy(&dpu_enc->enc_lock);
-}
-
 void dpu_encoder_helper_split_config(
 		struct dpu_encoder_phys *phys_enc,
 		enum dpu_intf interface)
@@ -2346,7 +2329,6 @@ static const struct drm_encoder_helper_funcs dpu_encoder_helper_funcs = {
 };
 
 static const struct drm_encoder_funcs dpu_encoder_funcs = {
-		.destroy = dpu_encoder_destroy,
 		.late_register = dpu_encoder_late_register,
 		.early_unregister = dpu_encoder_early_unregister,
 };
@@ -2357,20 +2339,13 @@ struct drm_encoder *dpu_encoder_init(struct drm_device *dev,
 {
 	struct msm_drm_private *priv = dev->dev_private;
 	struct dpu_kms *dpu_kms = to_dpu_kms(priv->kms);
-	struct drm_encoder *drm_enc = NULL;
-	struct dpu_encoder_virt *dpu_enc = NULL;
-	int ret = 0;
+	struct dpu_encoder_virt *dpu_enc;
+	int ret;
 
-	dpu_enc = devm_kzalloc(dev->dev, sizeof(*dpu_enc), GFP_KERNEL);
-	if (!dpu_enc)
-		return ERR_PTR(-ENOMEM);
-
-	ret = drm_encoder_init(dev, &dpu_enc->base, &dpu_encoder_funcs,
-			       drm_enc_mode, NULL);
-	if (ret) {
-		devm_kfree(dev->dev, dpu_enc);
-		return ERR_PTR(ret);
-	}
+	dpu_enc = drmm_encoder_alloc(dev, struct dpu_encoder_virt, base,
+				     &dpu_encoder_funcs, drm_enc_mode, NULL);
+	if (IS_ERR(dpu_enc))
+		return ERR_CAST(dpu_enc);
 
 	drm_encoder_helper_add(&dpu_enc->base, &dpu_encoder_helper_funcs);
 
@@ -2380,8 +2355,10 @@ struct drm_encoder *dpu_encoder_init(struct drm_device *dev,
 	mutex_init(&dpu_enc->rc_lock);
 
 	ret = dpu_encoder_setup_display(dpu_enc, dpu_kms, disp_info);
-	if (ret)
-		goto fail;
+	if (ret) {
+		DPU_ERROR("failed to setup encoder\n");
+		return ERR_PTR(-ENOMEM);
+	}
 
 	atomic_set(&dpu_enc->frame_done_timeout_ms, 0);
 	atomic_set(&dpu_enc->frame_done_timeout_cnt, 0);
@@ -2397,13 +2374,6 @@ struct drm_encoder *dpu_encoder_init(struct drm_device *dev,
 	DPU_DEBUG_ENC(dpu_enc, "created\n");
 
 	return &dpu_enc->base;
-
-fail:
-	DPU_ERROR("failed to create encoder\n");
-	if (drm_enc)
-		dpu_encoder_destroy(drm_enc);
-
-	return ERR_PTR(ret);
 }
 
 int dpu_encoder_wait_for_event(struct drm_encoder *drm_enc,