The main focus of this series is to make VFIO follow the normal kernel convention of structure embedding for structure inheritance instead of linking using a 'void *opaque'. Here we focus on moving the vfio_device to be a member of every struct vfio_XX_device that is linked by a vfio_add_group_dev(). In turn this allows 'struct vfio_device *' to be used everwhere, and the public API out of vfio.c can be cleaned to remove places using 'struct device *' and 'void *' as surrogates to refer to the device. While this has the minor trade off of moving 'struct vfio_device' the clarity of the design is worth it. I can speak directly to this idea, as I've invested a fair amount of time carefully working backwards what all the type-erased APIs are supposed to be and it is certainly not trivial or intuitive. When we get into mdev land things become even more inscrutable, and while I now have a pretty clear picture, it was hard to obtain. I think this agrees with the kernel style ideal of being explicit in typing and not sacrificing clarity to create opaque structs. After this series the general rules are: - Any vfio_XX_device * can be obtained at no cost from a vfio_device * using container_of(), and the reverse is possible by &XXdev->vdev This is similar to how 'struct pci_device' and 'struct device' are interrelated. This allows 'device_data' to be completely removed from the vfio.c API. - The drvdata for a struct device points at the vfio_XX_device that belongs to the driver that was probed. drvdata is removed from the core code, and only used as part of the implementation of the struct device_driver. - The lifetime of vfio_XX_device and vfio_device are identical, they are the same memory. This follows the existing model where vfio_del_group_dev() blocks until all vfio_device_put()'s are completed. This in turn means the struct device_driver remove() blocks, and thus under the driver_lock() a bound driver must have a valid drvdata pointing at both vfio device structs. A following series exploits this further. Most vfio_XX_device structs have data that duplicates the 'struct device *dev' member of vfio_device, a following series removes that duplication too. v2: - Split the get/put changes out of "Simlpify the lifetime logic for vfio_device" - Add a patch to fix probe ordering in fsl-mc and remove FIXME - Add a patch to re-org pci probe - Add a patch to fix probe odering in pci and remove FIXME - Remove the **pf_dev output from get_pf_vdev() v1: https://lore.kernel.org/r/0-v1-7355d38b9344+17481-vfio1_jgg@xxxxxxxxxx Thanks, Jason Jason Gunthorpe (14): vfio: Remove extra put/gets around vfio_device->group vfio: Simplify the lifetime logic for vfio_device vfio: Split creation of a vfio_device into init and register ops vfio/platform: Use vfio_init/register/unregister_group_dev vfio/fsl-mc: Re-order vfio_fsl_mc_probe() vfio/fsl-mc: Use vfio_init/register/unregister_group_dev vfio/pci: Move VGA and VF initialization to functions vfio/pci: Re-order vfio_pci_probe() vfio/pci: Use vfio_init/register/unregister_group_dev vfio/mdev: Use vfio_init/register/unregister_group_dev vfio/mdev: Make to_mdev_device() into a static inline vfio: Make vfio_device_ops pass a 'struct vfio_device *' instead of 'void *' vfio/pci: Replace uses of vfio_device_data() with container_of vfio: Remove device_data from the vfio bus driver API Documentation/driver-api/vfio.rst | 48 ++-- drivers/vfio/fsl-mc/vfio_fsl_mc.c | 96 ++++--- drivers/vfio/fsl-mc/vfio_fsl_mc_private.h | 1 + drivers/vfio/mdev/mdev_private.h | 5 +- drivers/vfio/mdev/vfio_mdev.c | 57 ++-- drivers/vfio/pci/vfio_pci.c | 253 ++++++++++-------- drivers/vfio/pci/vfio_pci_private.h | 1 + drivers/vfio/platform/vfio_amba.c | 8 +- drivers/vfio/platform/vfio_platform.c | 21 +- drivers/vfio/platform/vfio_platform_common.c | 56 ++-- drivers/vfio/platform/vfio_platform_private.h | 5 +- drivers/vfio/vfio.c | 210 +++++---------- include/linux/vfio.h | 37 ++- 13 files changed, 397 insertions(+), 401 deletions(-) -- 2.30.2
