Hi Daniel,
On Wed, Feb 19, 2020 at 04:27:57PM +0100, Daniel Vetter wrote:
On Wed, Feb 19, 2020 at 3:35 PM Laurent Pinchart wrote:
On Wed, Feb 19, 2020 at 11:20:52AM +0100, Daniel Vetter wrote:
Well for the simple stuff at least, vblank, gem and minor cleanup I want to further split up as a demonstration.
v2: We need to clear drm_device->dev otherwise the debug drm printing after our cleanup hook (e.g. in drm_manged_release) will chase released memory and result in a use-after-free. Not really pretty, but oh well.
Signed-off-by: Daniel Vetter daniel.vetter@intel.com
drivers/gpu/drm/drm_drv.c | 48 ++++++++++++++++++++------------------- 1 file changed, 25 insertions(+), 23 deletions(-)
Is the managed API overhead, coupled with the fact that the code size doesn't get reduced, worth it for core code ?
I've mostly done this as an example, to show how if you do this consistently, you can drop a few if (is_it_set_up) checks and remove the onion unwinding with lots of gotos.
That's however more a matter of making the cleanup handlers idempotent than using a managed API, isn't it ?
I do think it's worth it from that pov, since long-term I want to get to a world where everything related to drm_device gets unwound with drmm_ actions. The logging output becomes fairly nice if you enable it :-)
But yeah stand-alone it's not a good pitch. Heck even the overall patch series is still a net loss I think, simply because this is just the bare minimum to get started. -Daniel
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c index 782fd5d6f8b2..1f7ab88d9435 100644 --- a/drivers/gpu/drm/drm_drv.c +++ b/drivers/gpu/drm/drm_drv.c @@ -580,6 +580,23 @@ static void drm_fs_inode_free(struct inode *inode)
- used.
*/
+static void drm_dev_init_release(struct drm_device *dev, void *res) +{
drm_legacy_ctxbitmap_cleanup(dev);drm_legacy_remove_map_hash(dev);drm_fs_inode_free(dev->anon_inode);put_device(dev->dev);/* Prevent use-after-free in drm_managed_release when debugging is* enabled. Slightly awkward, but can't really be helped. */dev->dev = NULL;mutex_destroy(&dev->master_mutex);mutex_destroy(&dev->clientlist_mutex);mutex_destroy(&dev->filelist_mutex);mutex_destroy(&dev->struct_mutex);drm_legacy_destroy_members(dev);+}
/**
- drm_dev_init - Initialise new DRM device
- @dev: DRM device
@@ -647,11 +664,15 @@ int drm_dev_init(struct drm_device *dev, mutex_init(&dev->clientlist_mutex); mutex_init(&dev->master_mutex);
ret = drmm_add_action(dev, drm_dev_init_release, NULL);if (ret)return ret;dev->anon_inode = drm_fs_inode_new(); if (IS_ERR(dev->anon_inode)) { ret = PTR_ERR(dev->anon_inode); DRM_ERROR("Cannot allocate anonymous inode: %d\n", ret);
goto err_free;
goto err; } if (drm_core_check_feature(dev, DRIVER_RENDER)) {@@ -688,19 +709,12 @@ int drm_dev_init(struct drm_device *dev, if (drm_core_check_feature(dev, DRIVER_GEM)) drm_gem_destroy(dev); err_ctxbitmap:
drm_legacy_ctxbitmap_cleanup(dev);drm_legacy_remove_map_hash(dev);err_minors: drm_minor_free(dev, DRM_MINOR_PRIMARY); drm_minor_free(dev, DRM_MINOR_RENDER);
drm_fs_inode_free(dev->anon_inode);-err_free:
put_device(dev->dev);mutex_destroy(&dev->master_mutex);mutex_destroy(&dev->clientlist_mutex);mutex_destroy(&dev->filelist_mutex);mutex_destroy(&dev->struct_mutex);drm_legacy_destroy_members(dev);+err:
drm_managed_release(dev);return ret;} EXPORT_SYMBOL(drm_dev_init); @@ -763,20 +777,8 @@ void drm_dev_fini(struct drm_device *dev) if (drm_core_check_feature(dev, DRIVER_GEM)) drm_gem_destroy(dev);
drm_legacy_ctxbitmap_cleanup(dev);drm_legacy_remove_map_hash(dev);drm_fs_inode_free(dev->anon_inode);drm_minor_free(dev, DRM_MINOR_PRIMARY); drm_minor_free(dev, DRM_MINOR_RENDER);put_device(dev->dev);mutex_destroy(&dev->master_mutex);mutex_destroy(&dev->clientlist_mutex);mutex_destroy(&dev->filelist_mutex);mutex_destroy(&dev->struct_mutex);drm_legacy_destroy_members(dev);} EXPORT_SYMBOL(drm_dev_fini);