Re: [PATCH v10 0/5] rust: add SRCU abstraction

["Onur Özkan" <work@onurozkan.dev>]

On Sat, 13 Jun 2026 09:40:06 +0300
Onur Özkan <work@onurozkan.dev> wrote:

> The immediate motivation is the Tyr reset infrastructure [1] which needs
> to serialize reset sensitive hardware access against reset and teardown
> paths. That reset series started to require many independent dependencies
> so this SRCU support is split out as a standalone Rust API to keep the
> reset series focused on the reset logic and easier to review, rebase and
> land.
> 
> 
> Changes since v9:
> 
> - SRCU initialization restructuring is now a separate patch (the first
>   one in this series).
> - Comment fix on C initialization functions.
> 
> 
> Changes since v8:
> 
> - Refactor srcu init handling to provide better init API (motivated by
>   the "mutex.h" initializers.
> - Use warn_on! instead of pr_warn! on leaked guard detection.
> 
> 
> Changes since v7:
> 
> - Moved synchronize_srcu() call inside "if srcu_readers_active()"
>   condition in "impl PinnedDrop for Srcu".
> - Improved comments on the synchronize_srcu() call in
>   "impl PinnedDrop for Srcu".
> 
> 
> Changes since v6:
> 
> - Removed "CONFIG_DEBUG_LOCK_ALLOC" condition from "rust/helpers/srcu.c"
>   and created a simple wrapper inside "include/linux/srcu.h" for it.
> 
> 
> Changes since v5:
> 
> - Created separate srcu_readers_active() variants for "srcutiny.h" and
>   "srcutree.h".
> 
> 
> Changes since v4:
> 
> - Exposed srcu_readers_active from C side and wired it to the Rust
>   helpers.
> - Used srcu_readers_active() in SRCU drop and logged with pr_warn if
>   there are leaked guards during the drop.
> 
> 
> Changes since v3 (which are for Sashiko notes [2]):
> 
> - Added rust helpers for srcu_barrier() and synchronize_srcu_expedited()
>   so the abstraction builds with CONFIG_TINY_SRCU, where these are
>   static inline functions.
> - Added missing INVARIANT comment in Srcu::new() about why the type
>   invariants hold after successful initialization.
> 
> 
> Changes since v2:
> 
> - Removed closure-based API.
> - Added #[doc(hidden)] on new_srcu macro.
> - Added #[must_use..] on srcu::Guard.
> - Improved the clean-up path (PinnedDrop implementation) which
>   eventually made read_lock safe with leaked guards.
> 
> 
> Changes since v1:
> 
> - Made the owned SRCU read-side guard API unsafe and added a safe closure
>   based helper for callers that do not need to keep the guard. This is to
>   avoid UB on the C side cleanup_srcu_struct where the SRCU struct is freed
>   while there are still active guards, which can happen if the caller leaks
>   the guard e.g., with mem::forget().
> - Improved doc comments.
> 
> 
> v1: https://lore.kernel.org/all/20260428103437.156236-1-work@onurozkan.dev
> v2: https://lore.kernel.org/all/20260502162833.34334-1-work@onurozkan.dev
> v3: https://lore.kernel.org/all/20260522054228.114814-1-work@onurozkan.dev
> v4: https://lore.kernel.org/all/20260525175706.124910-1-work@onurozkan.dev
> v5: https://lore.kernel.org/all/20260527174120.510447-1-work@onurozkan.dev
> v6: https://lore.kernel.org/all/20260527203615.163688-1-work@onurozkan.dev
> v7: https://lore.kernel.org/all/20260528062810.256212-1-work@onurozkan.dev
> v8: https://lore.kernel.org/all/20260529114449.112066-1-work@onurozkan.dev
> v9: https://lore.kernel.org/all/20260529134004.396743-1-work@onurozkan.dev
> 
> [1]: https://lore.kernel.org/all/20260416171728.205141-1-work@onurozkan.dev
> [2]: https://sashiko.dev/#/patchset/20260522054228.114814-1-work@onurozkan.dev?part=2
> 
> Onur Özkan (5):
>   srcu: make init_srcu_struct() consistently wrap __init_srcu_struct()
>   rust: helpers: add SRCU helpers
>   srcu: expose srcu_readers_active()
>   rust: sync: add SRCU abstraction
>   MAINTAINERS: add Rust SRCU files to SRCU entry
> 
>  MAINTAINERS              |   3 +
>  include/linux/srcu.h     |  29 ++++---
>  include/linux/srcutiny.h |  13 +++
>  include/linux/srcutree.h |  24 ++++++
>  kernel/rcu/srcutiny.c    |  14 ++--
>  kernel/rcu/srcutree.c    |  36 ++-------
>  rust/helpers/helpers.c   |   1 +
>  rust/helpers/srcu.c      |  35 ++++++++
>  rust/kernel/sync.rs      |   2 +
>  rust/kernel/sync/srcu.rs | 171 +++++++++++++++++++++++++++++++++++++++
>  10 files changed, 282 insertions(+), 46 deletions(-)
>  create mode 100644 rust/helpers/srcu.c
>  create mode 100644 rust/kernel/sync/srcu.rs
> 
> -- 
> 2.51.2
> 

A gentle ping on this series. Are there any remaining concerns with v10?

Regards,
Onur