diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/rcu/tree_plugin.h | 21 |
1 files changed, 13 insertions, 8 deletions
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 0bb1c1593ca4..3ed43f8cb029 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -397,6 +397,11 @@ static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp) return rnp->gp_tasks != NULL; } +/* Bias and limit values for ->rcu_read_lock_nesting. */ +#define RCU_NEST_BIAS INT_MAX +#define RCU_NEST_NMAX (-INT_MAX / 2) +#define RCU_NEST_PMAX (INT_MAX / 2) + /* * Preemptible RCU implementation for rcu_read_lock(). * Just increment ->rcu_read_lock_nesting, shared state will be updated @@ -405,6 +410,8 @@ static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp) void __rcu_read_lock(void) { current->rcu_read_lock_nesting++; + if (IS_ENABLED(CONFIG_PROVE_LOCKING)) + WARN_ON_ONCE(current->rcu_read_lock_nesting > RCU_NEST_PMAX); barrier(); /* critical section after entry code. */ } EXPORT_SYMBOL_GPL(__rcu_read_lock); @@ -424,20 +431,18 @@ void __rcu_read_unlock(void) --t->rcu_read_lock_nesting; } else { barrier(); /* critical section before exit code. */ - t->rcu_read_lock_nesting = INT_MIN; + t->rcu_read_lock_nesting = -RCU_NEST_BIAS; barrier(); /* assign before ->rcu_read_unlock_special load */ if (unlikely(READ_ONCE(t->rcu_read_unlock_special.s))) rcu_read_unlock_special(t); barrier(); /* ->rcu_read_unlock_special load before assign */ t->rcu_read_lock_nesting = 0; } -#ifdef CONFIG_PROVE_LOCKING - { - int rrln = READ_ONCE(t->rcu_read_lock_nesting); + if (IS_ENABLED(CONFIG_PROVE_LOCKING)) { + int rrln = t->rcu_read_lock_nesting; - WARN_ON_ONCE(rrln < 0 && rrln > INT_MIN / 2); + WARN_ON_ONCE(rrln < 0 && rrln > RCU_NEST_NMAX); } -#endif /* #ifdef CONFIG_PROVE_LOCKING */ } EXPORT_SYMBOL_GPL(__rcu_read_unlock); @@ -617,11 +622,11 @@ static void rcu_preempt_deferred_qs(struct task_struct *t) if (!rcu_preempt_need_deferred_qs(t)) return; if (couldrecurse) - t->rcu_read_lock_nesting -= INT_MIN; + t->rcu_read_lock_nesting -= RCU_NEST_BIAS; local_irq_save(flags); rcu_preempt_deferred_qs_irqrestore(t, flags); if (couldrecurse) - t->rcu_read_lock_nesting += INT_MIN; + t->rcu_read_lock_nesting += RCU_NEST_BIAS; } /* |