Merge branches 'pm-core', 'pm-qos', 'pm-domains' and 'pm-opp'

[linux.git] / kernel / rcu / tree_exp.h

diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h
index e59e1849b89aca14797999deb3e9e91bdd9b78c2..a7b639ccd46e0ade81946639ef1d50bdc2b68d21 100644 (file)
--- a/kernel/rcu/tree_exp.h
+++ b/kernel/rcu/tree_exp.h
@@ -20,16 +20,26 @@
  * Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
  */
 
-/* Wrapper functions for expedited grace periods.  */
+/*
+ * Record the start of an expedited grace period.
+ */
 static void rcu_exp_gp_seq_start(struct rcu_state *rsp)
 {
        rcu_seq_start(&rsp->expedited_sequence);
 }
+
+/*
+ * Record the end of an expedited grace period.
+ */
 static void rcu_exp_gp_seq_end(struct rcu_state *rsp)
 {
        rcu_seq_end(&rsp->expedited_sequence);
        smp_mb(); /* Ensure that consecutive grace periods serialize. */
 }
+
+/*
+ * Take a snapshot of the expedited-grace-period counter.
+ */
 static unsigned long rcu_exp_gp_seq_snap(struct rcu_state *rsp)
 {
        unsigned long s;
@@ -39,6 +49,12 @@ static unsigned long rcu_exp_gp_seq_snap(struct rcu_state *rsp)
        trace_rcu_exp_grace_period(rsp->name, s, TPS("snap"));
        return s;
 }
+
+/*
+ * Given a counter snapshot from rcu_exp_gp_seq_snap(), return true
+ * if a full expedited grace period has elapsed since that snapshot
+ * was taken.
+ */
 static bool rcu_exp_gp_seq_done(struct rcu_state *rsp, unsigned long s)
 {
        return rcu_seq_done(&rsp->expedited_sequence, s);
@@ -356,12 +372,11 @@ static void sync_rcu_exp_select_cpus(struct rcu_state *rsp,
                mask_ofl_test = 0;
                for_each_leaf_node_possible_cpu(rnp, cpu) {
                        struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu);
-                       struct rcu_dynticks *rdtp = &per_cpu(rcu_dynticks, cpu);
 
                        rdp->exp_dynticks_snap =
-                               atomic_add_return(0, &rdtp->dynticks);
+                               rcu_dynticks_snap(rdp->dynticks);
                        if (raw_smp_processor_id() == cpu ||
-                           !(rdp->exp_dynticks_snap & 0x1) ||
+                           rcu_dynticks_in_eqs(rdp->exp_dynticks_snap) ||
                            !(rnp->qsmaskinitnext & rdp->grpmask))
                                mask_ofl_test |= rdp->grpmask;
                }
@@ -380,13 +395,12 @@ static void sync_rcu_exp_select_cpus(struct rcu_state *rsp,
                for_each_leaf_node_possible_cpu(rnp, cpu) {
                        unsigned long mask = leaf_node_cpu_bit(rnp, cpu);
                        struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu);
-                       struct rcu_dynticks *rdtp = &per_cpu(rcu_dynticks, cpu);
 
                        if (!(mask_ofl_ipi & mask))
                                continue;
 retry_ipi:
-                       if (atomic_add_return(0, &rdtp->dynticks) !=
-                           rdp->exp_dynticks_snap) {
+                       if (rcu_dynticks_in_eqs_since(rdp->dynticks,
+                                                     rdp->exp_dynticks_snap)) {
                                mask_ofl_test |= mask;
                                continue;
                        }
@@ -623,6 +637,11 @@ void synchronize_sched_expedited(void)
 {
        struct rcu_state *rsp = &rcu_sched_state;
 
+       RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map) ||
+                        lock_is_held(&rcu_lock_map) ||
+                        lock_is_held(&rcu_sched_lock_map),
+                        "Illegal synchronize_sched_expedited() in RCU read-side critical section");
+
        /* If only one CPU, this is automatically a grace period. */
        if (rcu_blocking_is_gp())
                return;
@@ -692,6 +711,11 @@ void synchronize_rcu_expedited(void)
 {
        struct rcu_state *rsp = rcu_state_p;
 
+       RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map) ||
+                        lock_is_held(&rcu_lock_map) ||
+                        lock_is_held(&rcu_sched_lock_map),
+                        "Illegal synchronize_rcu_expedited() in RCU read-side critical section");
+
        if (rcu_scheduler_active == RCU_SCHEDULER_INACTIVE)
                return;
        _synchronize_rcu_expedited(rsp, sync_rcu_exp_handler);