drm: Add devm_drm_dev_alloc macro

Add a new macro helper to combine the usual init sequence in drivers,
consisting of a kzalloc + devm_drm_dev_init + drmm_add_final_kfree
triplet. This allows us to remove the rather unsightly
drmm_add_final_kfree from all currently merged drivers.

The kerneldoc is only added for this new function. Existing kerneldoc
and examples will be udated at the very end, since once all drivers
are converted over to devm_drm_dev_alloc we can unexport a lot of
interim functions and make the documentation for driver authors a lot
cleaner and less confusing. There will be only one true way to
initialize a drm_device at the end of this, which is going to be
devm_drm_dev_alloc.

v2:
- Actually explain what this is for in the commit message (Sam)
- Fix checkpatch issues (Sam)

Acked-by: Noralf Trønnes <noralf@tronnes.org>
Cc: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200415074034.175360-2-daniel.vetter@ffwll.ch

1 files changed, 23 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index c15c9b4540e1..bc38322f306e 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -739,6 +739,29 @@ int devm_drm_dev_init(struct device *parent,
 }
 EXPORT_SYMBOL(devm_drm_dev_init);
 
+void *__devm_drm_dev_alloc(struct device *parent, struct drm_driver *driver,
+			   size_t size, size_t offset)
+{
+	void *container;
+	struct drm_device *drm;
+	int ret;
+
+	container = kzalloc(size, GFP_KERNEL);
+	if (!container)
+		return ERR_PTR(-ENOMEM);
+
+	drm = container + offset;
+	ret = devm_drm_dev_init(parent, drm, driver);
+	if (ret) {
+		kfree(container);
+		return ERR_PTR(ret);
+	}
+	drmm_add_final_kfree(drm, container);
+
+	return container;
+}
+EXPORT_SYMBOL(__devm_drm_dev_alloc);
+
 /**
  * drm_dev_alloc - Allocate new DRM device
  * @driver: DRM driver to allocate device for