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 v5: - Created separate srcu_readers_active() variants for "srcutiny.h" and "srcutree.h". v5: https://lore.kernel.org/all/[email protected] 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. v4: https://lore.kernel.org/all/[email protected] 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. v3: https://lore.kernel.org/all/[email protected] 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. v2: https://lore.kernel.org/all/[email protected] 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/[email protected] [1]: https://lore.kernel.org/all/[email protected] [2]: https://sashiko.dev/#/patchset/[email protected]?part=2 Onur Özkan (4): 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/srcutiny.h | 13 +++ include/linux/srcutree.h | 24 ++++++ kernel/rcu/srcutiny.c | 2 +- kernel/rcu/srcutree.c | 25 ------ rust/helpers/helpers.c | 1 + rust/helpers/srcu.c | 39 +++++++++ rust/kernel/sync.rs | 2 + rust/kernel/sync/srcu.rs | 166 +++++++++++++++++++++++++++++++++++++++ 9 files changed, 249 insertions(+), 26 deletions(-) create mode 100644 rust/helpers/srcu.c create mode 100644 rust/kernel/sync/srcu.rs -- 2.51.2
