drm: Don't swallow error codes in drm_dev_alloc()

There are many reasons other than ENOMEM that drm_dev_init() can
fail. Return ERR_PTR rather than NULL to be able to distinguish
these in the caller.
Signed-off-by: Tom Gundersen <teg@jklm.no>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: http://patchwork.freedesktop.org/patch/msgid/20160921145919.13754-2-teg@jklm.no

drivers/gpu/drm/arc/arcpgu_drv.c

@@ -198,8 +198,8 @@ static int arcpgu_probe(struct platform_device *pdev)
 	int ret;
 
 	drm = drm_dev_alloc(&arcpgu_drm_driver, &pdev->dev);
-	if (!drm)
-		return -ENOMEM;
+	if (IS_ERR(drm))
+		return PTR_ERR(drm);
 
 	ret = arcpgu_load(drm);
 	if (ret)

drivers/gpu/drm/arm/hdlcd_drv.c

@@ -326,8 +326,8 @@ static int hdlcd_drm_bind(struct device *dev)
 		return -ENOMEM;
 
 	drm = drm_dev_alloc(&hdlcd_driver, dev);
-	if (!drm)
-		return -ENOMEM;
+	if (IS_ERR(drm))
+		return PTR_ERR(drm);
 
 	drm->dev_private = hdlcd;
 	dev_set_drvdata(dev, drm);

drivers/gpu/drm/arm/malidp_drv.c

@@ -311,8 +311,8 @@ static int malidp_bind(struct device *dev)
 		return ret;
 
 	drm = drm_dev_alloc(&malidp_driver, dev);
-	if (!drm) {
-		ret = -ENOMEM;
+	if (IS_ERR(drm)) {
+		ret = PTR_ERR(drm);
 		goto alloc_fail;
 	}
 

drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c

@@ -797,8 +797,8 @@ static int atmel_hlcdc_dc_drm_probe(struct platform_device *pdev)
 	int ret;
 
 	ddev = drm_dev_alloc(&atmel_hlcdc_dc_driver, &pdev->dev);
-	if (!ddev)
-		return -ENOMEM;
+	if (IS_ERR(ddev))
+		return PTR_ERR(ddev);
 
 	ret = atmel_hlcdc_dc_load(ddev);
 	if (ret)

drivers/gpu/drm/drm_drv.c

@@ -591,7 +591,7 @@ EXPORT_SYMBOL(drm_dev_init);
  * own struct should look at using drm_dev_init() instead.
  *
  * RETURNS:
- * Pointer to new DRM device, or NULL if out of memory.
+ * Pointer to new DRM device, or ERR_PTR on failure.
  */
 struct drm_device *drm_dev_alloc(struct drm_driver *driver,
 				 struct device *parent)
@@ -601,12 +601,12 @@ struct drm_device *drm_dev_alloc(struct drm_driver *driver,
 
 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 	if (!dev)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
 	ret = drm_dev_init(dev, driver, parent);
 	if (ret) {
 		kfree(dev);
-		return NULL;
+		return ERR_PTR(ret);
 	}
 
 	return dev;

drivers/gpu/drm/drm_pci.c

@@ -236,8 +236,8 @@ int drm_get_pci_dev(struct pci_dev *pdev, const struct pci_device_id *ent,
 	DRM_DEBUG("\n");
 
 	dev = drm_dev_alloc(driver, &pdev->dev);
-	if (!dev)
-		return -ENOMEM;
+	if (IS_ERR(dev))
+		return PTR_ERR(dev);
 
 	ret = pci_enable_device(pdev);
 	if (ret)

drivers/gpu/drm/drm_platform.c

@@ -48,8 +48,8 @@ static int drm_get_platform_dev(struct platform_device *platdev,
 	DRM_DEBUG("\n");
 
 	dev = drm_dev_alloc(driver, &platdev->dev);
-	if (!dev)
-		return -ENOMEM;
+	if (IS_ERR(dev))
+		return PTR_ERR(dev);
 
 	dev->platformdev = platdev;
 

drivers/gpu/drm/etnaviv/etnaviv_drv.c

@@ -529,8 +529,8 @@ static int etnaviv_bind(struct device *dev)
 	int ret;
 
 	drm = drm_dev_alloc(&etnaviv_drm_driver, dev);
-	if (!drm)
-		return -ENOMEM;
+	if (IS_ERR(drm))
+		return PTR_ERR(drm);
 
 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 	if (!priv) {

drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c

@@ -402,8 +402,8 @@ static int fsl_dcu_drm_probe(struct platform_device *pdev)
 	fsl_dev->tcon = fsl_tcon_init(dev);
 
 	drm = drm_dev_alloc(driver, dev);
-	if (!drm) {
-		ret = -ENOMEM;
+	if (IS_ERR(drm)) {
+		ret = PTR_ERR(drm);
 		goto disable_pix_clk;
 	}
 

drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c

@@ -207,8 +207,8 @@ static int kirin_drm_bind(struct device *dev)
 	int ret;
 
 	drm_dev = drm_dev_alloc(driver, dev);
-	if (!drm_dev)
-		return -ENOMEM;
+	if (IS_ERR(drm_dev))
+		return PTR_ERR(drm_dev);
 
 	drm_dev->platformdev = to_platform_device(dev);
 

drivers/gpu/drm/mediatek/mtk_drm_drv.c

@@ -294,8 +294,8 @@ static int mtk_drm_bind(struct device *dev)
 	int ret;
 
 	drm = drm_dev_alloc(&mtk_drm_driver, dev);
-	if (!drm)
-		return -ENOMEM;
+	if (IS_ERR(drm))
+		return PTR_ERR(drm);
 
 	drm->dev_private = private;
 	private->drm = drm;

drivers/gpu/drm/msm/msm_drv.c

@@ -347,9 +347,9 @@ static int msm_drm_init(struct device *dev, struct drm_driver *drv)
 	int ret;
 
 	ddev = drm_dev_alloc(drv, dev);
-	if (!ddev) {
+	if (IS_ERR(ddev)) {
 		dev_err(dev, "failed to allocate drm_device\n");
-		return -ENOMEM;
+		return PTR_ERR(ddev);
 	}
 
 	platform_set_drvdata(pdev, ddev);

drivers/gpu/drm/nouveau/nouveau_drm.c

@@ -1067,8 +1067,8 @@ nouveau_platform_device_create(const struct nvkm_device_tegra_func *func,
 		goto err_free;
 
 	drm = drm_dev_alloc(&driver_platform, &pdev->dev);
-	if (!drm) {
-		err = -ENOMEM;
+	if (IS_ERR(drm)) {
+		err = PTR_ERR(drm);
 		goto err_free;
 	}
 

drivers/gpu/drm/rcar-du/rcar_du_drv.c

@@ -316,8 +316,8 @@ static int rcar_du_probe(struct platform_device *pdev)
 	rcdu->info = of_match_device(rcar_du_of_table, rcdu->dev)->data;
 
 	ddev = drm_dev_alloc(&rcar_du_driver, &pdev->dev);
-	if (!ddev)
-		return -ENOMEM;
+	if (IS_ERR(ddev))
+		return PTR_ERR(ddev);
 
 	rcdu->ddev = ddev;
 	ddev->dev_private = rcdu;

drivers/gpu/drm/rockchip/rockchip_drm_drv.c

@@ -143,8 +143,8 @@ static int rockchip_drm_bind(struct device *dev)
 	int ret;
 
 	drm_dev = drm_dev_alloc(&rockchip_drm_driver, dev);
-	if (!drm_dev)
-		return -ENOMEM;
+	if (IS_ERR(drm_dev))
+		return PTR_ERR(drm_dev);
 
 	dev_set_drvdata(dev, drm_dev);
 

drivers/gpu/drm/sti/sti_drv.c

@@ -365,8 +365,8 @@ static int sti_bind(struct device *dev)
 	int ret;
 
 	ddev = drm_dev_alloc(&sti_driver, dev);
-	if (!ddev)
-		return -ENOMEM;
+	if (IS_ERR(ddev))
+		return PTR_ERR(ddev);
 
 	ddev->platformdev = to_platform_device(dev);
 

drivers/gpu/drm/sun4i/sun4i_drv.c

@@ -121,8 +121,8 @@ static int sun4i_drv_bind(struct device *dev)
 	int ret;
 
 	drm = drm_dev_alloc(&sun4i_drv_driver, dev);
-	if (!drm)
-		return -ENOMEM;
+	if (IS_ERR(drm))
+		return PTR_ERR(drm);
 
 	drv = devm_kzalloc(dev, sizeof(*drv), GFP_KERNEL);
 	if (!drv) {

drivers/gpu/drm/tegra/drm.c

@@ -983,8 +983,8 @@ static int host1x_drm_probe(struct host1x_device *dev)
 	int err;
 
 	drm = drm_dev_alloc(driver, &dev->dev);
-	if (!drm)
-		return -ENOMEM;
+	if (IS_ERR(drm))
+		return PTR_ERR(drm);
 
 	dev_set_drvdata(&dev->dev, drm);
 

drivers/gpu/drm/udl/udl_drv.c

@@ -86,8 +86,8 @@ static int udl_usb_probe(struct usb_interface *interface,
 	int r;
 
 	dev = drm_dev_alloc(&driver, &interface->dev);
-	if (!dev)
-		return -ENOMEM;
+	if (IS_ERR(dev))
+		return PTR_ERR(dev);
 
 	r = drm_dev_register(dev, (unsigned long)udev);
 	if (r)

drivers/gpu/drm/vc4/vc4_drv.c

@@ -233,8 +233,8 @@ static int vc4_drm_bind(struct device *dev)
 		return -ENOMEM;
 
 	drm = drm_dev_alloc(&vc4_drm_driver, dev);
-	if (!drm)
-		return -ENOMEM;
+	if (IS_ERR(drm))
+		return PTR_ERR(drm);
 	platform_set_drvdata(pdev, drm);
 	vc4->dev = drm;
 	drm->dev_private = vc4;

drivers/gpu/drm/vgem/vgem_drv.c

@@ -334,8 +334,8 @@ static int __init vgem_init(void)
 	int ret;
 
 	vgem_device = drm_dev_alloc(&vgem_driver, NULL);
-	if (!vgem_device) {
-		ret = -ENOMEM;
+	if (IS_ERR(vgem_device)) {
+		ret = PTR_ERR(vgem_device);
 		goto out;
 	}
 

drivers/gpu/drm/virtio/virtgpu_drm_bus.c

@@ -54,8 +54,8 @@ int drm_virtio_init(struct drm_driver *driver, struct virtio_device *vdev)
 	int ret;
 
 	dev = drm_dev_alloc(driver, &vdev->dev);
-	if (!dev)
-		return -ENOMEM;
+	if (IS_ERR(dev))
+		return PTR_ERR(dev);
 	dev->virtdev = vdev;
 	vdev->priv = dev;