[PATCH 04/44] drm/vgem: Use devm_drm_dev_alloc

[Daniel Vetter]

This means we also need to slightly restructure the exit code, so that
final cleanup of the drm_device is triggered by unregistering the
platform device. Note that devres is both clean up when the driver is
unbound (not the case for vgem, we don't bind), and also when unregistering
the device (very much the case for vgem). Therefore we can rely on devres
even though vgem isn't a proper platform device driver.

This also somewhat untangles the load code, since the drm and platform device
setup are no longer interleaved, but two distinct steps.

Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
Cc: Emil Velikov <emil.velikov at collabora.com>
Cc: Sean Paul <seanpaul at chromium.org>
Cc: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Sam Ravnborg <sam at ravnborg.org>
Cc: Rob Clark <robdclark at chromium.org>
---
 drivers/gpu/drm/vgem/vgem_drv.c | 51 ++++++++++-----------------------
 1 file changed, 15 insertions(+), 36 deletions(-)

diff --git a/drivers/gpu/drm/vgem/vgem_drv.c b/drivers/gpu/drm/vgem/vgem_drv.c
index ec1a8ebb6f1b..2ce3b547312a 100644
--- a/drivers/gpu/drm/vgem/vgem_drv.c
+++ b/drivers/gpu/drm/vgem/vgem_drv.c
@@ -427,16 +427,8 @@ static int vgem_prime_mmap(struct drm_gem_object *obj,
 	return 0;
 }
 
-static void vgem_release(struct drm_device *dev)
-{
-	struct vgem_device *vgem = container_of(dev, typeof(*vgem), drm);
-
-	platform_device_unregister(vgem->platform);
-}
-
 static struct drm_driver vgem_driver = {
 	.driver_features		= DRIVER_GEM | DRIVER_RENDER,
-	.release			= vgem_release,
 	.open				= vgem_open,
 	.postclose			= vgem_postclose,
 	.gem_free_object_unlocked	= vgem_gem_free_object,
@@ -469,48 +461,35 @@ static struct drm_driver vgem_driver = {
 static int __init vgem_init(void)
 {
 	int ret;
+	struct platform_device *pdev;
 
-	vgem_device = kzalloc(sizeof(*vgem_device), GFP_KERNEL);
-	if (!vgem_device)
-		return -ENOMEM;
-
-	vgem_device->platform =
-		platform_device_register_simple("vgem", -1, NULL, 0);
-	if (IS_ERR(vgem_device->platform)) {
-		ret = PTR_ERR(vgem_device->platform);
-		goto out_free;
-	}
+	pdev = platform_device_register_simple("vgem", -1, NULL, 0);
+	if (IS_ERR(pdev))
+		return PTR_ERR(vgem_device->platform);
 
-	dma_coerce_mask_and_coherent(&vgem_device->platform->dev,
+	dma_coerce_mask_and_coherent(&pdev->dev,
 				     DMA_BIT_MASK(64));
-	ret = drm_dev_init(&vgem_device->drm, &vgem_driver,
-			   &vgem_device->platform->dev);
-	if (ret)
-		goto out_unregister;
-	drmm_add_final_kfree(&vgem_device->drm, vgem_device);
+
+	vgem_device = devm_drm_dev_alloc(&pdev->dev, &vgem_driver,
+					 struct vgem_device, drm);
+	if (IS_ERR(vgem_device)) {
+		platform_device_unregister(pdev);
+		return PTR_ERR(vgem_device);
+	}
+	vgem_device->platform = pdev;
 
 	/* Final step: expose the device/driver to userspace */
 	ret = drm_dev_register(&vgem_device->drm, 0);
 	if (ret)
-		goto out_put;
+		return ret;
 
 	return 0;
-
-out_put:
-	drm_dev_put(&vgem_device->drm);
-	return ret;
-
-out_unregister:
-	platform_device_unregister(vgem_device->platform);
-out_free:
-	kfree(vgem_device);
-	return ret;
 }
 
 static void __exit vgem_exit(void)
 {
 	drm_dev_unregister(&vgem_device->drm);
-	drm_dev_put(&vgem_device->drm);
+	platform_device_unregister(vgem_device->platform);
 }
 
 module_init(vgem_init);
-- 
2.25.1