drm: Compile out legacy chunks from struct drm_device

This means some very few #ifdef in code, but it allows us to
enlist the compiler to make sure this stuff isn't used anymore.

More important, only legacy drivers change drm_device (for the
legacy_dev_list shadow attach management), therefore this is
prep to allow modern drivers to have a const driver struct. Which
is nice, because there's a ton of function pointers in there.

Acked-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Review-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20201104100425.1922351-2-daniel.vetter@ffwll.ch

drivers/gpu/drm/drm_file.c

@@ -258,9 +258,11 @@ void drm_file_free(struct drm_file *file)
 		  (long)old_encode_dev(file->minor->kdev->devt),
 		  atomic_read(&dev->open_count));
 
+#ifdef CONFIG_DRM_LEGACY
 	if (drm_core_check_feature(dev, DRIVER_LEGACY) &&
 	    dev->driver->preclose)
 		dev->driver->preclose(dev, file);
+#endif
 
 	if (drm_core_check_feature(dev, DRIVER_LEGACY))
 		drm_legacy_lock_release(dev, file->filp);

drivers/gpu/drm/drm_vblank.c

@@ -209,9 +209,12 @@ static u32 __get_vblank_counter(struct drm_device *dev, unsigned int pipe)
 
 		if (crtc->funcs->get_vblank_counter)
 			return crtc->funcs->get_vblank_counter(crtc);
-	} else if (dev->driver->get_vblank_counter) {
+	}
+#ifdef CONFIG_DRM_LEGACY
+	else if (dev->driver->get_vblank_counter) {
 		return dev->driver->get_vblank_counter(dev, pipe);
 	}
+#endif
 
 	return drm_vblank_no_hw_counter(dev, pipe);
 }
@@ -429,9 +432,12 @@ static void __disable_vblank(struct drm_device *dev, unsigned int pipe)
 
 		if (crtc->funcs->disable_vblank)
 			crtc->funcs->disable_vblank(crtc);
-	} else {
+	}
+#ifdef CONFIG_DRM_LEGACY
+	else {
 		dev->driver->disable_vblank(dev, pipe);
 	}
+#endif
 }
 
 /*
@@ -1096,9 +1102,12 @@ static int __enable_vblank(struct drm_device *dev, unsigned int pipe)
 
 		if (crtc->funcs->enable_vblank)
 			return crtc->funcs->enable_vblank(crtc);
-	} else if (dev->driver->enable_vblank) {
+	}
+#ifdef CONFIG_DRM_LEGACY
+	else if (dev->driver->enable_vblank) {
 		return dev->driver->enable_vblank(dev, pipe);
 	}
+#endif
 
 	return -EINVAL;
 }

include/drm/drm_drv.h

@@ -495,6 +495,7 @@ struct drm_driver {
 	 */
 	const struct file_operations *fops;
 
+#ifdef CONFIG_DRM_LEGACY
 	/* Everything below here is for legacy driver, never use! */
 	/* private: */
 
@@ -509,6 +510,7 @@ struct drm_driver {
 	int (*enable_vblank)(struct drm_device *dev, unsigned int pipe);
 	void (*disable_vblank)(struct drm_device *dev, unsigned int pipe);
 	int dev_priv_size;
+#endif
 };
 
 void *__devm_drm_dev_alloc(struct device *parent, struct drm_driver *driver,