[PATCH 0/4] ntsync documentation, selftests, and owner validation

This series improves ntsync without changing wait/wake semantics:

 1/4 — Align Documentation/userspace-api/ntsync.rst with
       include/uapi/linux/ntsync.h (ioctl macro names and struct layout).

 2/4 — Fix wake_all selftest: CREATE_EVENT returns an fd, not zero.

 3/4 — Add selftests for documented EINVAL cases (zero owner, non-zero
       pad, cross-instance object use).

 4/4 — Reject wait ioctls when owner is zero, matching the documented
       uAPI (3/4 depends on 4/4 for the owner tests).

Patch 4/4 closes a spec gap: Documentation/userspace-api/ntsync.rst
requires EINVAL when wait owner is zero, but setup_wait() only validated
pad and flags.  Unlock/kill mutex ioctls already reject owner == 0.

Testing:
- scripts/checkpatch.pl --strict --no-tree: clean (4/4 patches)
- make headers && make -C tools/testing/selftests TARGETS=drivers/ntsync
- Kernel 7.1.0-ntsync-test+ (CONFIG_NTSYNC=y), QEMU x86_64 initramfs:
  tools/testing/selftests/drivers/ntsync/ntsync — 12/12 PASS,
  including wake_all and wait_args_validation
- On 6.17.0-35-generic with the distro ntsync.ko (without patch 4/4):
  wait_args_validation fails on owner==0 (wait proceeds instead of
  EINVAL), confirming the gap this series fixes

Elizabeth Figura <[email protected]>
[email protected]
---
 Documentation/userspace-api/ntsync.rst         | 22 +++++-----
 tools/testing/selftests/drivers/ntsync/ntsync.c | 45 ++++++++++++++++++++
 drivers/misc/ntsync.c                          |  3 ++
 3 files changed, 59 insertions(+), 11 deletions(-)

Iván Ezequiel Rodriguez (4):
  docs: ntsync: align uAPI ioctl names and struct layout with ntsync.h
  selftests: ntsync: fix wake_all CREATE_EVENT fd expectation
  selftests: ntsync: add wait argument validation tests
  ntsync: reject wait ioctls with zero owner

--
2.43.0