simplify the mdev interface v6

[Christoph Hellwig]

Alex, does this series look good to you now?

On Sat, Jul 09, 2022 at 06:54:36AM +0200, Christoph Hellwig wrote:
> Hi all,
> 
> this series signigicantly simplies the mdev driver interface by following
> the patterns for device model interaction used elsewhere in the kernel.
> 
> Changes since v5:
>  - rebased to the latest vfio/next branch
>  - drop the last patch again
>  - make sure show_available_instances works properly for the internallly
>    tracked case
> 
> Changes since v4:
>  - move the kobject_put later in mdev_device_release 
>  - add a Fixes tag for the first patch
>  - add another patch to remove an extra kobject_get/put
> 
> Changes since v3:
>  - make the sysfs_name and pretty_name fields pointers instead of arrays
>  - add an i915 cleanup to prepare for the above
> 
> Changes since v2:
>  - rebased to vfio/next
>  - fix a pre-existing memory leak in i915 instead of making it worse
>  - never manipulate if ->available_instances if drv->get_available is
>    provided
>  - keep a parent reference for the mdev_type
>  - keep a few of the sysfs.c helper function around
>  - improve the documentation for the parent device lifetime
>  - minor spellig / formatting fixes
> 
> Changes since v1:
>  - embedd the mdev_parent into a different sub-structure in i916
>  - remove headers now inclued by mdev.h from individual source files
>  - pass an array of mdev_types to mdev_register_parent
>  - add additional patches to implement all attributes on the
>    mdev_type in the core code
> 
> Diffstat:
>  Documentation/driver-api/vfio-mediated-device.rst |   26 +-
>  Documentation/s390/vfio-ap.rst                    |    2 
>  Documentation/s390/vfio-ccw.rst                   |    2 
>  drivers/gpu/drm/i915/gvt/aperture_gm.c            |   20 +-
>  drivers/gpu/drm/i915/gvt/gvt.h                    |   42 ++--
>  drivers/gpu/drm/i915/gvt/kvmgt.c                  |  168 ++++-------------
>  drivers/gpu/drm/i915/gvt/vgpu.c                   |  210 +++++++---------------
>  drivers/s390/cio/cio.h                            |    4 
>  drivers/s390/cio/vfio_ccw_drv.c                   |   12 -
>  drivers/s390/cio/vfio_ccw_ops.c                   |   51 -----
>  drivers/s390/cio/vfio_ccw_private.h               |    2 
>  drivers/s390/crypto/vfio_ap_ops.c                 |   68 +------
>  drivers/s390/crypto/vfio_ap_private.h             |    6 
>  drivers/vfio/mdev/mdev_core.c                     |  190 ++++---------------
>  drivers/vfio/mdev/mdev_driver.c                   |    7 
>  drivers/vfio/mdev/mdev_private.h                  |   32 ---
>  drivers/vfio/mdev/mdev_sysfs.c                    |  189 ++++++++++---------
>  include/linux/mdev.h                              |   77 ++++----
>  samples/vfio-mdev/mbochs.c                        |  103 +++-------
>  samples/vfio-mdev/mdpy.c                          |  115 +++---------
>  samples/vfio-mdev/mtty.c                          |   94 +++------
>  21 files changed, 463 insertions(+), 957 deletions(-)
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