3 files changed, 10 insertions, 24 deletions

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 497f139056c7..afc5e32f0da4 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1763,14 +1763,14 @@ out:
  * Clean up any old requests for the just-ended grace period.  Also return
  * whether any additional grace periods have been requested.
  */
-static int rcu_future_gp_cleanup(struct rcu_state *rsp, struct rcu_node *rnp)
+static bool rcu_future_gp_cleanup(struct rcu_state *rsp, struct rcu_node *rnp)
 {
         int c = rnp->completed;
-        int needmore;
+        bool needmore;
         struct rcu_data *rdp = this_cpu_ptr(rsp->rda);
 
         need_future_gp_element(rnp, c) = 0;
-        needmore = need_future_gp_element(rnp, c + 1);
+        needmore = need_any_future_gp(rnp);
         trace_rcu_future_gp(rnp, rdp, c,
                             needmore ? TPS("CleanupMore") : TPS("Cleanup"));
         return needmore;
@@ -2113,7 +2113,6 @@ static void rcu_gp_cleanup(struct rcu_state *rsp)
 {
         unsigned long gp_duration;
         bool needgp = false;
-        int nocb = 0;
         struct rcu_data *rdp;
         struct rcu_node *rnp = rcu_get_root(rsp);
         struct swait_queue_head *sq;
@@ -2152,7 +2151,7 @@ static void rcu_gp_cleanup(struct rcu_state *rsp)
                 if (rnp == rdp->mynode)
                         needgp = __note_gp_changes(rsp, rnp, rdp) || needgp;
                 /* smp_mb() provided by prior unlock-lock pair. */
-                nocb += rcu_future_gp_cleanup(rsp, rnp);
+                needgp = rcu_future_gp_cleanup(rsp, rnp) || needgp;
                 sq = rcu_nocb_gp_get(rnp);
                 raw_spin_unlock_irq_rcu_node(rnp);
                 rcu_nocb_gp_cleanup(sq);
@@ -2162,13 +2161,18 @@ static void rcu_gp_cleanup(struct rcu_state *rsp)
         }
         rnp = rcu_get_root(rsp);
         raw_spin_lock_irq_rcu_node(rnp); /* Order GP before ->completed update. */
-        rcu_nocb_gp_set(rnp, nocb);
 
         /* Declare grace period done. */
         WRITE_ONCE(rsp->completed, rsp->gpnum);
         trace_rcu_grace_period(rsp->name, rsp->completed, TPS("end"));
         rsp->gp_state = RCU_GP_IDLE;
+        /* Check for GP requests since above loop. */
         rdp = this_cpu_ptr(rsp->rda);
+        if (need_any_future_gp(rnp)) {
+                trace_rcu_future_gp(rnp, rdp, rsp->completed - 1,
+                                    TPS("CleanupMore"));
+                needgp = true;
+        }
         /* Advance CBs to reduce false positives below. */
         needgp = rcu_advance_cbs(rsp, rnp, rdp) || needgp;
         if (needgp || cpu_needs_another_gp(rsp, rdp)) {
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index 18b091474ffa..bd1103763551 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -469,7 +469,6 @@ static void print_cpu_stall_info_end(void);
 static void zero_cpu_stall_ticks(struct rcu_data *rdp);
 static void increment_cpu_stall_ticks(void);
 static bool rcu_nocb_cpu_needs_barrier(struct rcu_state *rsp, int cpu);
-static void rcu_nocb_gp_set(struct rcu_node *rnp, int nrq);
 static struct swait_queue_head *rcu_nocb_gp_get(struct rcu_node *rnp);
 static void rcu_nocb_gp_cleanup(struct swait_queue_head *sq);
 static void rcu_init_one_nocb(struct rcu_node *rnp);
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 640ea927d8a4..313b77d9cf06 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -1780,19 +1780,6 @@ static void rcu_nocb_gp_cleanup(struct swait_queue_head *sq)
         swake_up_all(sq);
 }
 
-/*
- * Set the root rcu_node structure's ->need_future_gp field
- * based on the sum of those of all rcu_node structures.  This does
- * double-count the root rcu_node structure's requests, but this
- * is necessary to handle the possibility of a rcu_nocb_kthread()
- * having awakened during the time that the rcu_node structures
- * were being updated for the end of the previous grace period.
- */
-static void rcu_nocb_gp_set(struct rcu_node *rnp, int nrq)
-{
-        need_future_gp_element(rnp, rnp->completed + 1) += nrq;
-}
-
 static struct swait_queue_head *rcu_nocb_gp_get(struct rcu_node *rnp)
 {
         return &rnp->nocb_gp_wq[rnp->completed & 0x1];
@@ -2495,10 +2482,6 @@ static void rcu_nocb_gp_cleanup(struct swait_queue_head *sq)
 {
 }
 
-static void rcu_nocb_gp_set(struct rcu_node *rnp, int nrq)
-{
-}
-
 static struct swait_queue_head *rcu_nocb_gp_get(struct rcu_node *rnp)
 {
         return NULL;