[Intel-gfx] [PATCH 00/12] Remove vfio_mdev.c, mdev_parent_ops and more

[Jason Gunthorpe]

Prologue
========

This is series #3 in part of a larger work that arose from the minor
remark that the mdev_parent_ops indirection shim is useless and
complicates things.

It applies on top of Alex's current tree and requires the prior two
series.

This series achieves the removal of vfio_mdev.c. The future patches are all
focused on leveraging the changes made in the prior series to simplify the
API and device operation.

A preview of the future series's is here:
  https://github.com/jgunthorpe/linux/pull/3/commits

========

The mdev bus's core part for managing the lifecycle of devices is mostly
as one would expect for a driver core bus subsystem.

However instead of having a normal 'struct device_driver' and binding the
actual mdev drivers through the standard driver core mechanisms it open
codes this with the struct mdev_parent_ops and provides a single driver
that shims between the VFIO core and the actual device driver.

Make every one of the mdev drivers implement an actual struct mdev_driver
and directly call vfio_register_group_dev() in the probe() function for
the mdev.

Squash what is left of the mdev_parent_ops into the mdev_driver and remap
create(), remove() and mdev_attr_groups to their driver core
equivalents. Arrange to bind the created mdev_device to the mdev_driver
that is provided by the end driver.

The actual execution flow doesn't change much, eg what was
parent_ops->create is now device_driver->probe and it is called at almost
the exact same time - except under the normal control of the driver core.

This allows deleting the entire mdev_drvdata, and tidying some of the
sysfs. Many places in the drivers start using container_of()

This cleanly splits the mdev sysfs GUID lifecycle management stuff from
the vfio_device implementation part, the only VFIO special part of mdev
that remains is the mdev specific iommu intervention.

Thanks,
Jason

Jason Gunthorpe (12):
  vfio/mdev: Remove CONFIG_VFIO_MDEV_DEVICE
  vfio/mdev: Allow the mdev_parent_ops to specify the device driver to
    bind
  vfio/mtty: Convert to use vfio_register_group_dev()
  vfio/mdpy: Convert to use vfio_register_group_dev()
  vfio/mbochs: Convert to use vfio_register_group_dev()
  vfio/ap_ops: Convert to use vfio_register_group_dev()
  vfio/ccw: Convert to use vfio_register_group_dev()
  vfio/gvt: Convert to use vfio_register_group_dev()
  vfio/mdev: Remove mdev_parent_ops dev_attr_groups
  vfio/mdev: Remove mdev_parent_ops
  vfio/mdev: Use the driver core to create the 'remove' file
  vfio/mdev: Remove mdev drvdata

 .../driver-api/vfio-mediated-device.rst       |  55 ++---
 Documentation/s390/vfio-ap.rst                |   1 -
 arch/s390/Kconfig                             |   2 +-
 drivers/gpu/drm/i915/Kconfig                  |   2 +-
 drivers/gpu/drm/i915/gvt/kvmgt.c              | 210 +++++++++--------
 drivers/s390/cio/vfio_ccw_drv.c               |  21 +-
 drivers/s390/cio/vfio_ccw_ops.c               | 136 ++++++-----
 drivers/s390/cio/vfio_ccw_private.h           |   5 +
 drivers/s390/crypto/vfio_ap_ops.c             | 138 ++++++-----
 drivers/s390/crypto/vfio_ap_private.h         |   2 +
 drivers/vfio/mdev/Kconfig                     |   7 -
 drivers/vfio/mdev/Makefile                    |   1 -
 drivers/vfio/mdev/mdev_core.c                 |  65 ++++--
 drivers/vfio/mdev/mdev_driver.c               |  10 +-
 drivers/vfio/mdev/mdev_private.h              |   4 +-
 drivers/vfio/mdev/mdev_sysfs.c                |  37 ++-
 drivers/vfio/mdev/vfio_mdev.c                 | 180 ---------------
 drivers/vfio/vfio.c                           |   6 +-
 include/linux/mdev.h                          |  86 +------
 include/linux/vfio.h                          |   4 +
 samples/Kconfig                               |   6 +-
 samples/vfio-mdev/mbochs.c                    | 166 +++++++------
 samples/vfio-mdev/mdpy.c                      | 162 +++++++------
 samples/vfio-mdev/mtty.c                      | 218 +++++++-----------
 24 files changed, 649 insertions(+), 875 deletions(-)
 delete mode 100644 drivers/vfio/mdev/vfio_mdev.c

-- 
2.31.1