| Message ID | 20170121105825.27661-1-chris@chris-wilson.co.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Den 21.01.2017 11:58, skrev Chris Wilson: > 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 responsible 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 > > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> > Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> > Cc: Daniel Vetter <daniel.vetter@ffwll.ch> > --- > drivers/gpu/drm/drm_drv.c | 56 +++++++++++++++++++++++++++++++++-------------- > include/drm/drm_drv.h | 11 ++++++++++ > 2 files changed, 50 insertions(+), 17 deletions(-) > > diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c > index 1b11ab628da7..517718e4f6e4 100644 > --- a/drivers/gpu/drm/drm_drv.c > +++ b/drivers/gpu/drm/drm_drv.c > @@ -553,6 +553,39 @@ 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. drm_dev_fini() should only Looks like the end of the sentence is missing. Noralf. > + * > + * 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) > +{ > + 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 > @@ -598,23 +631,12 @@ static void drm_dev_release(struct kref *ref) > { > struct drm_device *dev = container_of(ref, struct drm_device, ref); > > - 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..bc5865ad0bbd 100644 > --- a/include/drm/drm_drv.h > +++ b/include/drm/drm_drv.h > @@ -103,6 +103,15 @@ 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. > + */ > + 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 +460,8 @@ 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);
On Sat, Jan 21, 2017 at 12:02:03PM +0100, Noralf Trønnes wrote: > > Den 21.01.2017 11:58, skrev Chris Wilson: > >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 responsible 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 > > > >Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> > >Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> > >Cc: Daniel Vetter <daniel.vetter@ffwll.ch> > >--- > > drivers/gpu/drm/drm_drv.c | 56 +++++++++++++++++++++++++++++++++-------------- > > include/drm/drm_drv.h | 11 ++++++++++ > > 2 files changed, 50 insertions(+), 17 deletions(-) > > > >diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c > >index 1b11ab628da7..517718e4f6e4 100644 > >--- a/drivers/gpu/drm/drm_drv.c > >+++ b/drivers/gpu/drm/drm_drv.c > >@@ -553,6 +553,39 @@ 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. drm_dev_fini() should only > > Looks like the end of the sentence is missing. Ah, started then moved it to the note about ref-count. -Chris
Hi Chris, Thank you for the patch. On Saturday 21 Jan 2017 10:58:25 Chris Wilson wrote: > 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 responsible 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 This takes my comments into account, thank you for that. Do you have a patch that shows usage of the release callback in a driver ? > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> > Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> > Cc: Daniel Vetter <daniel.vetter@ffwll.ch> > --- > drivers/gpu/drm/drm_drv.c | 56 ++++++++++++++++++++++++++++++-------------- > include/drm/drm_drv.h | 11 ++++++++++ > 2 files changed, 50 insertions(+), 17 deletions(-) > > diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c > index 1b11ab628da7..517718e4f6e4 100644 > --- a/drivers/gpu/drm/drm_drv.c > +++ b/drivers/gpu/drm/drm_drv.c > @@ -553,6 +553,39 @@ 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. drm_dev_fini() should only > + * > + * 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) > +{ > + 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 > @@ -598,23 +631,12 @@ static void drm_dev_release(struct kref *ref) > { > struct drm_device *dev = container_of(ref, struct drm_device, ref); > > - 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..bc5865ad0bbd 100644 > --- a/include/drm/drm_drv.h > +++ b/include/drm/drm_drv.h > @@ -103,6 +103,15 @@ 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. > + */ > + 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 +460,8 @@ 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);
On Sat, Jan 21, 2017 at 11:21:28PM +0200, Laurent Pinchart wrote: > Hi Chris, > > Thank you for the patch. > > On Saturday 21 Jan 2017 10:58:25 Chris Wilson wrote: > > 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 responsible 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 > > This takes my comments into account, thank you for that. Do you have a patch > that shows usage of the release callback in a driver ? I haven't yet dared start to split i915 between pci-device teardown and system teardown, but https://cgit.freedesktop.org/~ickle/linux-2.6/commit/?h=prescheduler&id=00a6ab3689ad09a0f2ea1df8e4a03a38721d2328 shows a use of driver->release to avoid the memory corruption with dmabuf versus the virtual device. vgem should also provide a useful example. -Chris
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c index 1b11ab628da7..517718e4f6e4 100644 --- a/drivers/gpu/drm/drm_drv.c +++ b/drivers/gpu/drm/drm_drv.c @@ -553,6 +553,39 @@ 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. drm_dev_fini() should only + * + * 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) +{ + 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 @@ -598,23 +631,12 @@ static void drm_dev_release(struct kref *ref) { struct drm_device *dev = container_of(ref, struct drm_device, ref); - 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..bc5865ad0bbd 100644 --- a/include/drm/drm_drv.h +++ b/include/drm/drm_drv.h @@ -103,6 +103,15 @@ 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. + */ + 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 +460,8 @@ 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);
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 responsible 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 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> --- drivers/gpu/drm/drm_drv.c | 56 +++++++++++++++++++++++++++++++++-------------- include/drm/drm_drv.h | 11 ++++++++++ 2 files changed, 50 insertions(+), 17 deletions(-)