From: Ye Liu <[email protected]> Introduce for_each_process_rculock(), for_each_thread_rculock() and for_each_process_thread_rculock() macros that combine the existing iteration macros with scoped_guard(rcu), so that the RCU read lock is automatically acquired before iteration and released when the loop exits — including via break, goto, or return.
The rest of the series converts manual rcu_read_lock()/ rcu_read_unlock() and guard(rcu)() pairs across mm/, kernel/, fs/, lib/ and security/ to use the new macros. Suggested by Michal Hocko for the oom_kill path [2]. Signed-off-by: Ye Liu <[email protected]> --- Changes since v3 [4]: - Fix patch 5 (cpu/hotplug): title and commit message incorrectly said "thread iterator" and "for_each_thread_rculock" while the code converts for_each_process() to for_each_process_rculock(). Note: Patches 4, 11, and 13 received automated reviews from sashiko-bot in the v3 thread [4] that were verified as false positives: - Patch 4: claimed the folio lock is dropped before collect_procs(), leading to a NULL deref on folio->mapping; the lock is held in all call paths. - Patch 11: claimed mixing goto/scope-based cleanup in alloc_retstack_tasklist(); the goto free label handles memory cleanup, not lock management. - Patch 13: claimed mixing goto/scope-based cleanup in __set_oom_adj(); goto err_unlock manages oom_adj_mutex while scoped_guard(rcu) manages the RCU read lock — different resources. Changes since v2 [3]: - Split the kernel/ patch into per-subsystem patches, as the combined patch could not be applied (Peter Zijlstra, Steven Rostedt). - Move changelog below the --- separator so it is excluded from the commit message (Lorenzo Stoakes). - Indent loop body in macro definitions to show scoped_guard scope (Lorenzo Stoakes). Changes since v1 [1]: - Rename macros from *_rcu to *_rculock, as suggested by Steven Rostedt and acked by Thomas Gleixner, to avoid confusion with existing *_rcu() list iterators that expect the caller to hold the RCU read lock. - Improve the comment on for_each_process_thread_rculock() to document that 'break' only exits the inner loop and 'goto' is needed to exit both loops (Thomas Gleixner). - Rename the stale 'unlock:' label to 'out:' in hung_task.c, as noted by Günther Noack. - Clarify in patch 4 that page_pgoff() is safe outside the RCU read-side critical section (SJ Park). - CC all relevant maintainers on every patch (Lorenzo Stoakes). - Drop the mm: prefix from patch 1, as the macros are in include/linux/sched/signal.h (Michal Hocko). [1] https://lore.kernel.org/all/[email protected]/ [2] https://lore.kernel.org/all/[email protected]/ [3] https://lore.kernel.org/all/[email protected]/ [4] https://lore.kernel.org/all/[email protected]/ Ye Liu (15): sched: introduce for_each_process_rculock and for_each_thread_rculock mm/oom_kill: convert process/thread iterators to for_each_*_rculock mm/ksm: convert process iterator to for_each_process_rculock mm/memory-failure: convert process iterator to for_each_process_rculock cpu/hotplug: convert process iterator to for_each_process_rculock freezer: convert thread iterator to for_each_thread_rculock hung_task: convert process/thread iterators to for_each_*_rculock locking/lockdep: convert process/thread iterators to for_each_*_rculock rcu: convert process/thread iterator to for_each_process_thread_rculock sched: convert process/thread iterators to for_each_*_rculock tracing/fgraph: convert process/thread iterator to for_each_process_thread_rculock unwind: convert process/thread iterator to for_each_process_thread_rculock fs: convert process/thread iterators to for_each_*_rculock lib: convert process iterator to for_each_process_rculock security/landlock: convert thread iterator to for_each_thread_rculock fs/proc/base.c | 4 +--- fs/resctrl/rdtgroup.c | 8 ++------ include/linux/sched/signal.h | 26 ++++++++++++++++++++++++++ kernel/cpu.c | 4 +--- kernel/freezer.c | 4 +--- kernel/hung_task.c | 11 ++++------- kernel/locking/lockdep.c | 4 +--- kernel/rcu/update.c | 4 +--- kernel/sched/core.c | 3 +-- kernel/sched/debug.c | 4 +--- kernel/trace/fgraph.c | 8 ++------ kernel/unwind/deferred.c | 3 +-- lib/is_single_threaded.c | 5 +---- mm/ksm.c | 4 +--- mm/memory-failure.c | 16 ++++------------ mm/oom_kill.c | 20 +++++--------------- security/landlock/tsync.c | 8 ++------ 17 files changed, 55 insertions(+), 81 deletions(-) -- 2.25.1
