1 files changed, 16 insertions, 23 deletions

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index fd2f582a6db0..bcd659e65dfd 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1790,24 +1790,23 @@ static bool __note_gp_changes(struct rcu_state *rsp, struct rcu_node *rnp,
 
         raw_lockdep_assert_held_rcu_node(rnp);
 
-        /* Handle the ends of any preceding grace periods first. */
-        if (rdp->completed == rnp->completed &&
-            !unlikely(READ_ONCE(rdp->gpwrap))) {
-
-                /* No grace period end, so just accelerate recent callbacks. */
-                ret = rcu_accelerate_cbs(rsp, rnp, rdp);
-
-        } else {
-
-                /* Advance callbacks. */
-                ret = rcu_advance_cbs(rsp, rnp, rdp);
+        if (rdp->gp_seq == rnp->gp_seq)
+                return false; /* Nothing to do. */
 
+        /* Handle the ends of any preceding grace periods first. */
+        if (rcu_seq_completed_gp(rdp->gp_seq, rnp->gp_seq) ||
+            unlikely(READ_ONCE(rdp->gpwrap))) {
+                ret = rcu_advance_cbs(rsp, rnp, rdp); /* Advance callbacks. */
                 /* Remember that we saw this grace-period completion. */
                 rdp->completed = rnp->completed;
-                trace_rcu_grace_period(rsp->name, rdp->gpnum, TPS("cpuend"));
+                trace_rcu_grace_period(rsp->name, rdp->gp_seq, TPS("cpuend"));
+        } else {
+                ret = rcu_accelerate_cbs(rsp, rnp, rdp); /* Recent callbacks. */
         }
 
-        if (rdp->gpnum != rnp->gpnum || unlikely(READ_ONCE(rdp->gpwrap))) {
+        /* Now handle the beginnings of any new-to-this-CPU grace periods. */
+        if (rcu_seq_new_gp(rdp->gp_seq, rnp->gp_seq) ||
+            unlikely(READ_ONCE(rdp->gpwrap))) {
                 /*
                  * If the current grace period is waiting for this CPU,
                  * set up to detect a quiescent state, otherwise don't
@@ -1823,8 +1822,7 @@ static bool __note_gp_changes(struct rcu_state *rsp, struct rcu_node *rnp,
                 WRITE_ONCE(rdp->gpwrap, false);
                 rcu_gpnum_ovf(rnp, rdp);
         }
-        if (rdp->gp_seq != rnp->gp_seq)
-                rdp->gp_seq = rnp->gp_seq;
+        rdp->gp_seq = rnp->gp_seq;  /* Remember new grace-period state. */
         return ret;
 }
 
@@ -1836,8 +1834,7 @@ static void note_gp_changes(struct rcu_state *rsp, struct rcu_data *rdp)
 
         local_irq_save(flags);
         rnp = rdp->mynode;
-        if ((rdp->gpnum == READ_ONCE(rnp->gpnum) &&
-             rdp->completed == READ_ONCE(rnp->completed) &&
+        if ((rdp->gp_seq == rcu_seq_current(&rnp->gp_seq) &&
              !unlikely(READ_ONCE(rdp->gpwrap))) || /* w/out lock. */
             !raw_spin_trylock_rcu_node(rnp)) { /* irqs already off, so later. */
                 local_irq_restore(flags);
@@ -3286,12 +3283,8 @@ static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp)
             !rcu_segcblist_restempty(&rdp->cblist, RCU_NEXT_READY_TAIL))
                 return 1;
 
-        /* Has another RCU grace period completed?  */
-        if (READ_ONCE(rnp->completed) != rdp->completed) /* outside lock */
-                return 1;
-
-        /* Has a new RCU grace period started? */
-        if (READ_ONCE(rnp->gpnum) != rdp->gpnum ||
+        /* Have RCU grace period completed or started?  */
+        if (rcu_seq_current(&rnp->gp_seq) != rdp->gp_seq ||
             unlikely(READ_ONCE(rdp->gpwrap))) /* outside lock */
                 return 1;