diff options
| -rw-r--r-- | kernel/rcu/tree.h | 5 | ||||
| -rw-r--r-- | kernel/rcu/tree_plugin.h | 8 |
2 files changed, 12 insertions, 1 deletions
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index 0f69a79c5b7d..3eeb919e26a2 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -172,6 +172,11 @@ struct rcu_node { /* queued on this rcu_node structure that */ /* are blocking the current grace period, */ /* there can be no such task. */ + struct completion boost_completion; + /* Used to ensure that the rt_mutex used */ + /* to carry out the boosting is fully */ + /* released with no future boostee accesses */ + /* before that rt_mutex is re-initialized. */ unsigned long boost_time; /* When to start boosting (jiffies). */ struct task_struct *boost_kthread_task; diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 5da9f9b3abc9..9c811879d31e 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -427,8 +427,10 @@ void rcu_read_unlock_special(struct task_struct *t) #ifdef CONFIG_RCU_BOOST /* Unboost if we were boosted. */ - if (rbmp) + if (rbmp) { rt_mutex_unlock(rbmp); + complete(&rnp->boost_completion); + } #endif /* #ifdef CONFIG_RCU_BOOST */ /* @@ -1202,10 +1204,14 @@ static int rcu_boost(struct rcu_node *rnp) t = container_of(tb, struct task_struct, rcu_node_entry); rt_mutex_init_proxy_locked(&mtx, t); t->rcu_boost_mutex = &mtx; + init_completion(&rnp->boost_completion); raw_spin_unlock_irqrestore(&rnp->lock, flags); rt_mutex_lock(&mtx); /* Side effect: boosts task t's priority. */ rt_mutex_unlock(&mtx); /* Keep lockdep happy. */ + /* Wait until boostee is done accessing mtx before reinitializing. */ + wait_for_completion(&rnp->boost_completion); + return ACCESS_ONCE(rnp->exp_tasks) != NULL || ACCESS_ONCE(rnp->boost_tasks) != NULL; } |