diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 17b5abf999ca..b3684b284677 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2199,8 +2199,8 @@ static void rcu_report_unblock_qs_rnp(struct rcu_state *rsp, unsigned long mask; struct rcu_node *rnp_p; - WARN_ON_ONCE(rsp == &rcu_bh_state || rsp == &rcu_sched_state); - if (rnp->qsmask != 0 || rcu_preempt_blocked_readers_cgp(rnp)) { + if (rcu_state_p == &rcu_sched_state || rsp != rcu_state_p || + rnp->qsmask != 0 || rcu_preempt_blocked_readers_cgp(rnp)) { raw_spin_unlock_irqrestore(&rnp->lock, flags); return; /* Still need more quiescent states! */ } @@ -2208,9 +2208,8 @@ static void rcu_report_unblock_qs_rnp(struct rcu_state *rsp, rnp_p = rnp->parent; if (rnp_p == NULL) { /* - * Either there is only one rcu_node in the tree, - * or tasks were kicked up to root rcu_node due to - * CPUs going offline. + * Only one rcu_node structure in the tree, so don't + * try to report up to its nonexistent parent! */ rcu_report_qs_rsp(rsp, flags); return; @@ -2713,8 +2712,29 @@ static void force_qs_rnp(struct rcu_state *rsp, return; } if (rnp->qsmask == 0) { - rcu_initiate_boost(rnp, flags); /* releases rnp->lock */ - continue; + if (rcu_state_p == &rcu_sched_state || + rsp != rcu_state_p || + rcu_preempt_blocked_readers_cgp(rnp)) { + /* + * No point in scanning bits because they + * are all zero. But we might need to + * priority-boost blocked readers. + */ + rcu_initiate_boost(rnp, flags); + /* rcu_initiate_boost() releases rnp->lock */ + continue; + } + if (rnp->parent && + (rnp->parent->qsmask & rnp->grpmask)) { + /* + * Race between grace-period + * initialization and task exiting RCU + * read-side critical section: Report. + */ + rcu_report_unblock_qs_rnp(rsp, rnp, flags); + /* rcu_report_unblock_qs_rnp() rlses ->lock */ + continue; + } } cpu = rnp->grplo; bit = 1; @@ -2729,15 +2749,6 @@ static void force_qs_rnp(struct rcu_state *rsp, if (mask != 0) { /* Idle/offline CPUs, report. */ rcu_report_qs_rnp(mask, rsp, rnp, flags); - } else if (rnp->parent && - list_empty(&rnp->blkd_tasks) && - !rnp->qsmask && - (rnp->parent->qsmask & rnp->grpmask)) { - /* - * Race between grace-period initialization and task - * existing RCU read-side critical section, report. - */ - rcu_report_unblock_qs_rnp(rsp, rnp, flags); } else { /* Nothing to do here, so just drop the lock. */ raw_spin_unlock_irqrestore(&rnp->lock, flags);