[PATCH 02/44] drm: Add devm_drm_dev_alloc macro

[Daniel Vetter]

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.

Cc: Paul Kocialkowski <paul.kocialkowski at bootlin.com>
Cc: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
---
 drivers/gpu/drm/drm_drv.c | 23 +++++++++++++++++++++++
 include/drm/drm_drv.h     | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 56 insertions(+)

diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 1bb4f636b83c..9e60b784b3ac 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
diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
index e7c6ea261ed1..26776be5a21e 100644
--- a/include/drm/drm_drv.h
+++ b/include/drm/drm_drv.h
@@ -626,6 +626,39 @@ int devm_drm_dev_init(struct device *parent,
 		      struct drm_device *dev,
 		      struct drm_driver *driver);
 
+void* __devm_drm_dev_alloc(struct device *parent, struct drm_driver *driver,
+			   size_t size, size_t offset);
+
+/**
+ * devm_drm_dev_alloc - Resource managed allocation of a &drm_device instance
+ * @parent: Parent device object
+ * @driver: DRM driver
+ * @type: the type of the struct which contains struct &drm_device
+ * @member: the name of the &drm_device within @type.
+ *
+ * This allocates and initialize a new DRM device. No device registration is done.
+ * Call drm_dev_register() to advertice the device to user space and register it
+ * with other core subsystems. This should be done last in the device
+ * initialization sequence to make sure userspace can't access an inconsistent
+ * state.
+ *
+ * The initial ref-count of the object is 1. Use drm_dev_get() and
+ * drm_dev_put() to take and drop further ref-counts.
+ *
+ * It is recommended that drivers embed &struct drm_device into their own device
+ * structure.
+ *
+ * Note that this manages the lifetime of the resulting &drm_device
+ * automatically using devres. The DRM device initialized with this function is
+ * automatically put on driver detach using drm_dev_put().
+ *
+ * RETURNS:
+ * Pointer to new DRM device, or ERR_PTR on failure.
+ */
+#define devm_drm_dev_alloc(parent, driver, type, member) \
+	((type *) __devm_drm_dev_alloc(parent, driver, sizeof(type), \
+				       offsetof(type, member)))
+
 struct drm_device *drm_dev_alloc(struct drm_driver *driver,
 				 struct device *parent);
 int drm_dev_register(struct drm_device *dev, unsigned long flags);
-- 
2.25.1