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.
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).
Patch 1 may trigger checkpatch "Macros with complex values should be
enclosed in parentheses" errors. These are false positives — the
scoped_guard() pattern is a control-flow construct, not a multi-
statement macro, and the same idiom is used elsewhere in the kernel.
Suggested by Michal Hocko for the oom_kill path [2].
[1] https://lore.kernel.org/all/[email protected]/
[2] https://lore.kernel.org/all/[email protected]/
Ye Liu (8):
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
kernel: convert process/thread iterators to for_each_*_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 | 25 +++++++++++++++++++++++++
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, 54 insertions(+), 81 deletions(-)
Signed-off-by: Ye Liu <[email protected]>
--
2.25.1
