[PATCH v2 0/3] drm, drm/vmwgfx: fixes and updates related to drm_master

[Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>]

Hi,

Just a note that only patch 2 changed from v1 to v2 of this series.

This series contains some improvements that Daniel Vetter proposed following a discussion on a recent series:
https://lore.kernel.org/lkml/20210712043508.11584-1-desmondcheongzx@gmail.com/

While preparing these patches, I also noticed some unprotected uses of drm_master in the vmwgfx driver that can be addressed by new functions from the previous series.

This series is thus broken up into three patches:

1. Switch from the outer drm_device.master_mutex to the inner drm_file.master_lookup_lock in drm_is_current_master.

2. Update the kerneldoc for drm leases to clarify usage and lifetime/locking rules.

3. Prevent potential use-after-free bugs by replacing calls to drm_master_get with drm_file_get_master in vmwgfx_surface.c.

v1 -> v2:
Changes to patch 2:
- Clarified description of lease fields in drm_master with suggestions from Daniel Vetter.
- Added an overview DOC: section for drm leases in drm-uapi.rst.
- Cleaned up function documentation in drm_lease.c to use kernel-doc formatting.

Best wishes,
Desmond

Desmond Cheong Zhi Xi (3):
  drm: use the lookup lock in drm_is_current_master
  drm: clarify usage of drm leases
  drm/vmwgfx: fix potential UAF in vmwgfx_surface.c

 Documentation/gpu/drm-uapi.rst          |  15 ++
 drivers/gpu/drm/drm_auth.c              |   9 +-
 drivers/gpu/drm/drm_lease.c             | 182 ++++++++++++++----------
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c |   4 +-
 include/drm/drm_auth.h                  |  67 +++++++--
 5 files changed, 187 insertions(+), 90 deletions(-)

-- 
2.25.1