rcu: Remove CPU-hotplug failsafe from force-quiescent-state code path

Now that quiescent states for newly offlined CPUs are reported either
when that CPU goes offline or at the end of grace-period initialization,
the CPU-hotplug failsafe in the force-quiescent-state code path is no
longer needed.

This commit therefore removes this failsafe.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

1 files changed, 1 insertions, 8 deletions

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 770f0df54015..5f1a11f1f7bc 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1188,14 +1188,6 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp)
                 smp_store_release(ruqp, true);
         }
 
-        /* Check for the CPU being offline. */
-        if (!(rdp->grpmask & rcu_rnp_online_cpus(rnp))) {
-                trace_rcu_fqs(rdp->rsp->name, rdp->gp_seq, rdp->cpu, TPS("ofl"));
-                rdp->offline_fqs++;
-                rcu_gpnum_ovf(rnp, rdp);
-                return 1;
-        }
-
         /*
          * A CPU running for an extended time within the kernel can
          * delay RCU grace periods.  When the CPU is in NO_HZ_FULL mode,
@@ -3718,6 +3710,7 @@ void rcu_cpu_starting(unsigned int cpu)
                 nbits = bitmap_weight(&oldmask, BITS_PER_LONG);
                 /* Allow lockless access for expedited grace periods. */
                 smp_store_release(&rsp->ncpus, rsp->ncpus + nbits); /* ^^^ */
+                rcu_gpnum_ovf(rnp, rdp); /* Offline-induced counter wrap? */
                 if (rnp->qsmask & mask) { /* RCU waiting on incoming CPU? */
                         /* Report QS -after- changing ->qsmaskinitnext! */
                         rcu_report_qs_rnp(mask, rsp, rnp, rnp->gp_seq, flags);