1 files changed, 36 insertions, 10 deletions

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 5d80925e7fc8..69a5611a7e7c 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -41,7 +41,6 @@
 #include <linux/export.h>
 #include <linux/completion.h>
 #include <linux/moduleparam.h>
-#include <linux/module.h>
 #include <linux/percpu.h>
 #include <linux/notifier.h>
 #include <linux/cpu.h>
@@ -60,7 +59,6 @@
 #include "tree.h"
 #include "rcu.h"
 
-MODULE_ALIAS("rcutree");
 #ifdef MODULE_PARAM_PREFIX
 #undef MODULE_PARAM_PREFIX
 #endif
@@ -1848,6 +1846,7 @@ static bool __note_gp_changes(struct rcu_state *rsp, struct rcu_node *rnp,
                               struct rcu_data *rdp)
 {
         bool ret;
+        bool need_gp;
 
         /* Handle the ends of any preceding grace periods first. */
         if (rdp->completed == rnp->completed &&
@@ -1874,9 +1873,10 @@ static bool __note_gp_changes(struct rcu_state *rsp, struct rcu_node *rnp,
                  */
                 rdp->gpnum = rnp->gpnum;
                 trace_rcu_grace_period(rsp->name, rdp->gpnum, TPS("cpustart"));
-                rdp->cpu_no_qs.b.norm = true;
+                need_gp = !!(rnp->qsmask & rdp->grpmask);
+                rdp->cpu_no_qs.b.norm = need_gp;
                 rdp->rcu_qs_ctr_snap = __this_cpu_read(rcu_qs_ctr);
-                rdp->core_needs_qs = !!(rnp->qsmask & rdp->grpmask);
+                rdp->core_needs_qs = need_gp;
                 zero_cpu_stall_ticks(rdp);
                 WRITE_ONCE(rdp->gpwrap, false);
         }
@@ -2344,7 +2344,7 @@ static void rcu_report_qs_rsp(struct rcu_state *rsp, unsigned long flags)
         WARN_ON_ONCE(!rcu_gp_in_progress(rsp));
         WRITE_ONCE(rsp->gp_flags, READ_ONCE(rsp->gp_flags) | RCU_GP_FLAG_FQS);
         raw_spin_unlock_irqrestore_rcu_node(rcu_get_root(rsp), flags);
-        swake_up(&rsp->gp_wq);  /* Memory barrier implied by swake_up() path. */
+        rcu_gp_kthread_wake(rsp);
 }
 
 /*
@@ -2970,7 +2970,7 @@ static void force_quiescent_state(struct rcu_state *rsp)
         }
         WRITE_ONCE(rsp->gp_flags, READ_ONCE(rsp->gp_flags) | RCU_GP_FLAG_FQS);
         raw_spin_unlock_irqrestore_rcu_node(rnp_old, flags);
-        swake_up(&rsp->gp_wq); /* Memory barrier implied by swake_up() path. */
+        rcu_gp_kthread_wake(rsp);
 }
 
 /*
@@ -3013,7 +3013,7 @@ __rcu_process_callbacks(struct rcu_state *rsp)
 /*
  * Do RCU core processing for the current CPU.
  */
-static void rcu_process_callbacks(struct softirq_action *unused)
+static __latent_entropy void rcu_process_callbacks(struct softirq_action *unused)
 {
         struct rcu_state *rsp;
 
@@ -3792,8 +3792,6 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp)
         rnp = rdp->mynode;
         mask = rdp->grpmask;
         raw_spin_lock_rcu_node(rnp);            /* irqs already disabled. */
-        rnp->qsmaskinitnext |= mask;
-        rnp->expmaskinitnext |= mask;
         if (!rdp->beenonline)
                 WRITE_ONCE(rsp->ncpus, READ_ONCE(rsp->ncpus) + 1);
         rdp->beenonline = true;  /* We have now been online. */
@@ -3860,6 +3858,32 @@ int rcutree_dead_cpu(unsigned int cpu)
         return 0;
 }
 
+/*
+ * Mark the specified CPU as being online so that subsequent grace periods
+ * (both expedited and normal) will wait on it.  Note that this means that
+ * incoming CPUs are not allowed to use RCU read-side critical sections
+ * until this function is called.  Failing to observe this restriction
+ * will result in lockdep splats.
+ */
+void rcu_cpu_starting(unsigned int cpu)
+{
+        unsigned long flags;
+        unsigned long mask;
+        struct rcu_data *rdp;
+        struct rcu_node *rnp;
+        struct rcu_state *rsp;
+
+        for_each_rcu_flavor(rsp) {
+                rdp = this_cpu_ptr(rsp->rda);
+                rnp = rdp->mynode;
+                mask = rdp->grpmask;
+                raw_spin_lock_irqsave_rcu_node(rnp, flags);
+                rnp->qsmaskinitnext |= mask;
+                rnp->expmaskinitnext |= mask;
+                raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+        }
+}
+
 #ifdef CONFIG_HOTPLUG_CPU
 /*
  * The CPU is exiting the idle loop into the arch_cpu_idle_dead()
@@ -4209,8 +4233,10 @@ void __init rcu_init(void)
          * or the scheduler are operational.
          */
         pm_notifier(rcu_pm_notify, 0);
-        for_each_online_cpu(cpu)
+        for_each_online_cpu(cpu) {
                 rcutree_prepare_cpu(cpu);
+                rcu_cpu_starting(cpu);
+        }
 }
 
 #include "tree_exp.h"