[PATCH v4 0/4] rust: serdev: Refactor

[Markus Probst <markus.probst@posteo.de>]

The following has been changed:
- introduce mutex to C serdev tty port controller
- introduce a new C serdev API to fix race conditions and simplify rust
  code. Should also be useful on the C side.
- fix race conditions
- simplify rust code

Signed-off-by: Markus Probst <markus.probst@posteo.de>
---
Changes in v4:
- fix issues reported by Sashiko:
  - add receive_lock to prevent deadlocks
- Link to v3: https://patch.msgid.link/20260930-rust_serdev_probe_refactor-v3-0-d1b6e77135e0@posteo.de

Changes in v3:
- add mutex
- Link to v2: https://patch.msgid.link/20260920-rust_serdev_probe_refactor-v2-0-43b855162f5d@posteo.de

Changes in v2:
- fix missing memory barriers in serdev apis
- use `tty_buffer_restart_work` instead of `tty_flip_buffer_push`
- use `tty_buffer_flush_work` instead of exclusively locking the mutex
- add `#[inline]` to `PrivateData::driver_data`
- remove patches for mutable references
- Link to v1: https://patch.msgid.link/20260906-rust_serdev_probe_refactor-v1-0-69cdae0074ec@posteo.de

---
Markus Probst (4):
      tty: serdev: Add mutex lock
      tty: serdev: Export functions to pause receive_buf callback calls
      rust: serdev: Replace `active` mutex with receive pause
      rust: serdev: Simplify callbacks

 drivers/tty/serdev/core.c           |  54 +++++++++++-
 drivers/tty/serdev/serdev-ttyport.c |  84 ++++++++++++++++--
 include/linux/serdev.h              |   8 +-
 rust/kernel/serdev.rs               | 167 ++++++++++++------------------------
 4 files changed, 188 insertions(+), 125 deletions(-)
---
base-commit: ec8bf8280261294a9b9b4520414b42704c7f9f6b
change-id: 20260905-rust_serdev_probe_refactor-0e2b044354a7