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.
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
---
drivers/gpu/drm/drm_drv.c | 67 +++++++++++++++++++++++++++++++++--------------
include/drm/drm_drv.h | 13 +++++++++
2 files changed, 60 insertions(+), 20 deletions(-)
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 72116978ec06..3db1f9003cc8 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -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 driver->release() callback and control
+ * the finalization explicitly.
*
* RETURNS:
* 0 on success, or error code on failure.
@@ -553,6 +556,43 @@ 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 state allocated by it. All driver state 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)
+{
+ WARN_ON(atomic_read(&dev->ref.refcount));
+
+ 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
* @parent: Parent device object
@@ -598,25 +638,12 @@ 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);
+ }
}
/**
diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
index 34ece393c639..3562f5be547e 100644
--- a/include/drm/drm_drv.h
+++ b/include/drm/drm_drv.h
@@ -103,6 +103,17 @@ struct drm_driver {
*
*/
void (*unload) (struct drm_device *);
+
+ /**
+ * @release:
+ *
+ * Optional callback for destroying device state 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 (*dma_ioctl) (struct drm_device *dev, void *data, struct drm_file *file_priv);
int (*dma_quiescent) (struct drm_device *);
int (*context_dtor) (struct drm_device *dev, int context);
@@ -451,6 +462,8 @@ 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);
--
2.11.0
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