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drm: Provide a driver hook for drm_dev_release()

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Some state is coupled into the device lifetime outside of the
load/unload timeframe and requires teardown during final unreference
from drm_dev_release(). For example, dmabufs hold both a device and
module reference and may live longer than expected (i.e. the current
pattern of the driver tearing down its state and then releasing a
reference to the drm device) and yet touch driver private state when
destroyed.

v2: Export drm_dev_fini() and move the responsibility for finalizing the
drm_device and freeing it to the release callback. (If no callback is
provided, the core will call drm_dev_fini() and kfree(dev) as before.)
v3: Remember to add drm_dev_fini() to drm_drv.h
v4: Tidy language for kerneldoc
v5: Cross reference from drm_dev_init() to note that driver->release()
allows for arbitrary embedding.
v6: Refer to driver data rather than driver state, as state is now
becoming associated with the struct drm_atomic_state and friends.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
[danvet: Use the proper reference for struct members, which is
&drm_driver.release.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20170202093632.31017-1-chris@chris-wilson.co.uk
This commit is contained in:
Chris Wilson 2017-02-02 09:36:32 +00:00 committed by Daniel Vetter
parent 8aaacbc0e5
commit f30c92576a
2 changed files with 58 additions and 20 deletions
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65
drivers/gpu/drm/drm_drv.c
View file

@ -465,7 +465,10 @@ static void drm_fs_inode_free(struct inode *inode)
* that do embed &struct drm_device it must be placed first in the overall
* structure, and the overall structure must be allocated using kmalloc(): The
* drm core's release function unconditionally calls kfree() on the @dev pointer
* when the final reference is released.
* when the final reference is released. To override this behaviour, and so
* allow embedding of the drm_device inside the driver's device struct at an
* arbitrary offset, you must supply a &drm_driver.release callback and control
* the finalization explicitly.
*
* RETURNS:
* 0 on success, or error code on failure.
@ -552,6 +555,41 @@ int drm_dev_init(struct drm_device *dev,
}
EXPORT_SYMBOL(drm_dev_init);
/**
* drm_dev_fini - Finalize a dead DRM device
* @dev: DRM device
*
* Finalize a dead DRM device. This is the converse to drm_dev_init() and
* frees up all data allocated by it. All driver private data should be
* finalized first. Note that this function does not free the @dev, that is
* left to the caller.
*
* The ref-count of @dev must be zero, and drm_dev_fini() should only be called
* from a &drm_driver.release callback.
*/
void drm_dev_fini(struct drm_device *dev)
{
drm_vblank_cleanup(dev);
if (drm_core_check_feature(dev, DRIVER_GEM))
drm_gem_destroy(dev);
drm_legacy_ctxbitmap_cleanup(dev);
drm_ht_remove(&dev->map_hash);
drm_fs_inode_free(dev->anon_inode);
drm_minor_free(dev, DRM_MINOR_PRIMARY);
drm_minor_free(dev, DRM_MINOR_RENDER);
drm_minor_free(dev, DRM_MINOR_CONTROL);
mutex_destroy(&dev->master_mutex);
mutex_destroy(&dev->ctxlist_mutex);
mutex_destroy(&dev->filelist_mutex);
mutex_destroy(&dev->struct_mutex);
kfree(dev->unique);
}
EXPORT_SYMBOL(drm_dev_fini);
/**
* drm_dev_alloc - Allocate new DRM device
* @driver: DRM driver to allocate device for
@ -598,25 +636,12 @@ static void drm_dev_release(struct kref *ref)
{
struct drm_device *dev = container_of(ref, struct drm_device, ref);
drm_vblank_cleanup(dev);
if (drm_core_check_feature(dev, DRIVER_GEM))
drm_gem_destroy(dev);
drm_legacy_ctxbitmap_cleanup(dev);
drm_ht_remove(&dev->map_hash);
drm_fs_inode_free(dev->anon_inode);
drm_minor_free(dev, DRM_MINOR_PRIMARY);
drm_minor_free(dev, DRM_MINOR_RENDER);
drm_minor_free(dev, DRM_MINOR_CONTROL);
mutex_destroy(&dev->master_mutex);
mutex_destroy(&dev->ctxlist_mutex);
mutex_destroy(&dev->filelist_mutex);
mutex_destroy(&dev->struct_mutex);
kfree(dev->unique);
kfree(dev);
if (dev->driver->release) {
dev->driver->release(dev);
} else {
drm_dev_fini(dev);
kfree(dev);
}
}
/**

13
include/drm/drm_drv.h
View file

@ -102,6 +102,17 @@ struct drm_driver {
*
*/
void (*unload) (struct drm_device *);
/**
* @release:
*
* Optional callback for destroying device data after the final
* reference is released, i.e. the device is being destroyed. Drivers
* using this callback are responsible for calling drm_dev_fini()
* to finalize the device and then freeing the struct themselves.
*/
void (*release) (struct drm_device *);
int (*set_busid)(struct drm_device *dev, struct drm_master *master);
/**
@ -437,6 +448,8 @@ extern unsigned int drm_debug;
int drm_dev_init(struct drm_device *dev,
struct drm_driver *driver,
struct device *parent);
void drm_dev_fini(struct drm_device *dev);
struct drm_device *drm_dev_alloc(struct drm_driver *driver,
struct device *parent);
int drm_dev_register(struct drm_device *dev, unsigned long flags);