From: Ye Liu <[email protected]> Replace the manual rcu_read_lock()/rcu_read_unlock() pair combined with for_each_process_thread() loop in kernel/rcu/update.c with for_each_process_thread_rculock(), which scopes the RCU read lock to the loop body via scoped_guard(rcu).
No functional change. Signed-off-by: Ye Liu <[email protected]> Acked-by: Michal Hocko <[email protected]> Reviewed-by: SJ Park <[email protected]> Reviewed-by: Lorenzo Stoakes (ARM) <[email protected]> Reviewed-by: Oleg Nesterov <[email protected]> --- Changes in v3: - Split from kernel/ patch in v2 (Peter Zijlstra, Steven Rostedt) Changes in v2: - Rename *_rcu to *_rculock kernel/rcu/update.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c index 2a778b8ab4ad..d8e0b5896db9 100644 --- a/kernel/rcu/update.c +++ b/kernel/rcu/update.c @@ -548,15 +548,13 @@ void synchronize_rcu_trivial_preempt(void) struct task_struct *t; smp_mb(); // Order prior accesses before grace-period start. - rcu_read_lock(); // Protect task list. - for_each_process_thread(g, t) { + for_each_process_thread_rculock(g, t) { if (t == current) continue; // Don't deadlock on ourselves! // Order later rcu_read_lock() on other tasks after QS. while (smp_load_acquire(&t->rcu_trivial_preempt_nesting)) continue; } - rcu_read_unlock(); } EXPORT_SYMBOL_GPL(synchronize_rcu_trivial_preempt); #endif // #if IS_ENABLED(CONFIG_TRIVIAL_PREEMPT_RCU) -- 2.25.1
