From: Zqiang Date: Wed, 13 Aug 2025 13:30:02 +0000 (+0800) Subject: rcu: Remove local_irq_save/restore() in rcu_preempt_deferred_qs_handler() X-Git-Tag: v6.18-rc1~86^2~2^2~4 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=42d590d100f2e47e47d974a902b9ed610e464824;p=thirdparty%2Fkernel%2Fstable.git rcu: Remove local_irq_save/restore() in rcu_preempt_deferred_qs_handler() The per-CPU rcu_data structure's ->defer_qs_iw field is initialized by IRQ_WORK_INIT_HARD(), which means that the subsequent invocation of rcu_preempt_deferred_qs_handler() will always be executed with interrupts disabled. This commit therefore removes the local_irq_save/restore() operations from rcu_preempt_deferred_qs_handler() and adds a call to lockdep_assert_irqs_disabled() in order to enable lockdep to diagnose mistaken invocations of this function from interrupts-enabled code. Signed-off-by: Zqiang Signed-off-by: Paul E. McKenney --- diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 4cd170b2d6551..d85763336b3c0 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -626,11 +626,10 @@ notrace void rcu_preempt_deferred_qs(struct task_struct *t) */ static void rcu_preempt_deferred_qs_handler(struct irq_work *iwp) { - unsigned long flags; struct rcu_data *rdp; + lockdep_assert_irqs_disabled(); rdp = container_of(iwp, struct rcu_data, defer_qs_iw); - local_irq_save(flags); /* * If the IRQ work handler happens to run in the middle of RCU read-side @@ -647,8 +646,6 @@ static void rcu_preempt_deferred_qs_handler(struct irq_work *iwp) */ if (rcu_preempt_depth() > 0) WRITE_ONCE(rdp->defer_qs_iw_pending, DEFER_QS_IDLE); - - local_irq_restore(flags); } /*