1 files changed, 134 insertions, 134 deletions

diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 53ae9598f798..3ec8160fc75f 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -46,7 +46,6 @@
 #include <linux/cpu.h>
 #include <linux/mutex.h>
 #include <linux/time.h>
-#include <linux/kernel_stat.h>
 
 #include "rcutree.h"
 
@@ -66,11 +65,11 @@ static struct lock_class_key rcu_node_class[NUM_RCU_LVLS];
         .signaled = RCU_GP_IDLE, \
         .gpnum = -300, \
         .completed = -300, \
-        .onofflock = __SPIN_LOCK_UNLOCKED(&name.onofflock), \
+        .onofflock = __RAW_SPIN_LOCK_UNLOCKED(&name.onofflock), \
         .orphan_cbs_list = NULL, \
         .orphan_cbs_tail = &name.orphan_cbs_list, \
         .orphan_qlen = 0, \
-        .fqslock = __SPIN_LOCK_UNLOCKED(&name.fqslock), \
+        .fqslock = __RAW_SPIN_LOCK_UNLOCKED(&name.fqslock), \
         .n_force_qs = 0, \
         .n_force_qs_ngp = 0, \
 }
@@ -81,9 +80,6 @@ DEFINE_PER_CPU(struct rcu_data, rcu_sched_data);
 struct rcu_state rcu_bh_state = RCU_STATE_INITIALIZER(rcu_bh_state);
 DEFINE_PER_CPU(struct rcu_data, rcu_bh_data);
 
-static int rcu_scheduler_active __read_mostly;
-
-
 /*
  * Return true if an RCU grace period is in progress.  The ACCESS_ONCE()s
  * permit this function to be invoked without holding the root rcu_node
@@ -157,6 +153,24 @@ long rcu_batches_completed_bh(void)
 EXPORT_SYMBOL_GPL(rcu_batches_completed_bh);
 
 /*
+ * Force a quiescent state for RCU BH.
+ */
+void rcu_bh_force_quiescent_state(void)
+{
+        force_quiescent_state(&rcu_bh_state, 0);
+}
+EXPORT_SYMBOL_GPL(rcu_bh_force_quiescent_state);
+
+/*
+ * Force a quiescent state for RCU-sched.
+ */
+void rcu_sched_force_quiescent_state(void)
+{
+        force_quiescent_state(&rcu_sched_state, 0);
+}
+EXPORT_SYMBOL_GPL(rcu_sched_force_quiescent_state);
+
+/*
  * Does the CPU have callbacks ready to be invoked?
  */
 static int
@@ -439,10 +453,10 @@ static void print_other_cpu_stall(struct rcu_state *rsp)
 
         /* Only let one CPU complain about others per time interval. */
 
-        spin_lock_irqsave(&rnp->lock, flags);
+        raw_spin_lock_irqsave(&rnp->lock, flags);
         delta = jiffies - rsp->jiffies_stall;
         if (delta < RCU_STALL_RAT_DELAY || !rcu_gp_in_progress(rsp)) {
-                spin_unlock_irqrestore(&rnp->lock, flags);
+                raw_spin_unlock_irqrestore(&rnp->lock, flags);
                 return;
         }
         rsp->jiffies_stall = jiffies + RCU_SECONDS_TILL_STALL_RECHECK;
@@ -452,13 +466,15 @@ static void print_other_cpu_stall(struct rcu_state *rsp)
          * due to CPU offlining.
          */
         rcu_print_task_stall(rnp);
-        spin_unlock_irqrestore(&rnp->lock, flags);
+        raw_spin_unlock_irqrestore(&rnp->lock, flags);
 
         /* OK, time to rat on our buddy... */
 
         printk(KERN_ERR "INFO: RCU detected CPU stalls:");
         rcu_for_each_leaf_node(rsp, rnp) {
+                raw_spin_lock_irqsave(&rnp->lock, flags);
                 rcu_print_task_stall(rnp);
+                raw_spin_unlock_irqrestore(&rnp->lock, flags);
                 if (rnp->qsmask == 0)
                         continue;
                 for (cpu = 0; cpu <= rnp->grphi - rnp->grplo; cpu++)
@@ -469,6 +485,10 @@ static void print_other_cpu_stall(struct rcu_state *rsp)
                smp_processor_id(), (long)(jiffies - rsp->gp_start));
         trigger_all_cpu_backtrace();
 
+        /* If so configured, complain about tasks blocking the grace period. */
+
+        rcu_print_detail_task_stall(rsp);
+
         force_quiescent_state(rsp, 0);  /* Kick them all. */
 }
 
@@ -481,11 +501,11 @@ static void print_cpu_stall(struct rcu_state *rsp)
                         smp_processor_id(), jiffies - rsp->gp_start);
         trigger_all_cpu_backtrace();
 
-        spin_lock_irqsave(&rnp->lock, flags);
-        if ((long)(jiffies - rsp->jiffies_stall) >= 0)
+        raw_spin_lock_irqsave(&rnp->lock, flags);
+        if (ULONG_CMP_GE(jiffies, rsp->jiffies_stall))
                 rsp->jiffies_stall =
                         jiffies + RCU_SECONDS_TILL_STALL_RECHECK;
-        spin_unlock_irqrestore(&rnp->lock, flags);
+        raw_spin_unlock_irqrestore(&rnp->lock, flags);
 
         set_need_resched();  /* kick ourselves to get things going. */
 }
@@ -545,12 +565,12 @@ static void note_new_gpnum(struct rcu_state *rsp, struct rcu_data *rdp)
         local_irq_save(flags);
         rnp = rdp->mynode;
         if (rdp->gpnum == ACCESS_ONCE(rnp->gpnum) || /* outside lock. */
-            !spin_trylock(&rnp->lock)) { /* irqs already off, retry later. */
+            !raw_spin_trylock(&rnp->lock)) { /* irqs already off, so later. */
                 local_irq_restore(flags);
                 return;
         }
         __note_new_gpnum(rsp, rnp, rdp);
-        spin_unlock_irqrestore(&rnp->lock, flags);
+        raw_spin_unlock_irqrestore(&rnp->lock, flags);
 }
 
 /*
@@ -609,12 +629,12 @@ rcu_process_gp_end(struct rcu_state *rsp, struct rcu_data *rdp)
         local_irq_save(flags);
         rnp = rdp->mynode;
         if (rdp->completed == ACCESS_ONCE(rnp->completed) || /* outside lock. */
-            !spin_trylock(&rnp->lock)) { /* irqs already off, retry later. */
+            !raw_spin_trylock(&rnp->lock)) { /* irqs already off, so later. */
                 local_irq_restore(flags);
                 return;
         }
         __rcu_process_gp_end(rsp, rnp, rdp);
-        spin_unlock_irqrestore(&rnp->lock, flags);
+        raw_spin_unlock_irqrestore(&rnp->lock, flags);
 }
 
 /*
@@ -659,12 +679,14 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags)
         struct rcu_data *rdp = rsp->rda[smp_processor_id()];
         struct rcu_node *rnp = rcu_get_root(rsp);
 
-        if (!cpu_needs_another_gp(rsp, rdp)) {
+        if (!cpu_needs_another_gp(rsp, rdp) || rsp->fqs_active) {
+                if (cpu_needs_another_gp(rsp, rdp))
+                        rsp->fqs_need_gp = 1;
                 if (rnp->completed == rsp->completed) {
-                        spin_unlock_irqrestore(&rnp->lock, flags);
+                        raw_spin_unlock_irqrestore(&rnp->lock, flags);
                         return;
                 }
-                spin_unlock(&rnp->lock);         /* irqs remain disabled. */
+                raw_spin_unlock(&rnp->lock);     /* irqs remain disabled. */
 
                 /*
                  * Propagate new ->completed value to rcu_node structures
@@ -672,9 +694,9 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags)
                  * of the next grace period to process their callbacks.
                  */
                 rcu_for_each_node_breadth_first(rsp, rnp) {
-                        spin_lock(&rnp->lock);   /* irqs already disabled. */
+                        raw_spin_lock(&rnp->lock); /* irqs already disabled. */
                         rnp->completed = rsp->completed;
-                        spin_unlock(&rnp->lock); /* irqs remain disabled. */
+                        raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */
                 }
                 local_irq_restore(flags);
                 return;
@@ -695,15 +717,15 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags)
                 rnp->completed = rsp->completed;
                 rsp->signaled = RCU_SIGNAL_INIT; /* force_quiescent_state OK. */
                 rcu_start_gp_per_cpu(rsp, rnp, rdp);
-                spin_unlock_irqrestore(&rnp->lock, flags);
+                raw_spin_unlock_irqrestore(&rnp->lock, flags);
                 return;
         }
 
-        spin_unlock(&rnp->lock);  /* leave irqs disabled. */
+        raw_spin_unlock(&rnp->lock);  /* leave irqs disabled. */
 
 
         /* Exclude any concurrent CPU-hotplug operations. */
-        spin_lock(&rsp->onofflock);  /* irqs already disabled. */
+        raw_spin_lock(&rsp->onofflock);  /* irqs already disabled. */
 
         /*
          * Set the quiescent-state-needed bits in all the rcu_node
@@ -723,21 +745,21 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags)
          * irqs disabled.
          */
         rcu_for_each_node_breadth_first(rsp, rnp) {
-                spin_lock(&rnp->lock);          /* irqs already disabled. */
+                raw_spin_lock(&rnp->lock);      /* irqs already disabled. */
                 rcu_preempt_check_blocked_tasks(rnp);
                 rnp->qsmask = rnp->qsmaskinit;
                 rnp->gpnum = rsp->gpnum;
                 rnp->completed = rsp->completed;
                 if (rnp == rdp->mynode)
                         rcu_start_gp_per_cpu(rsp, rnp, rdp);
-                spin_unlock(&rnp->lock);        /* irqs remain disabled. */
+                raw_spin_unlock(&rnp->lock);    /* irqs remain disabled. */
         }
 
         rnp = rcu_get_root(rsp);
-        spin_lock(&rnp->lock);                  /* irqs already disabled. */
+        raw_spin_lock(&rnp->lock);              /* irqs already disabled. */
         rsp->signaled = RCU_SIGNAL_INIT; /* force_quiescent_state now OK. */
-        spin_unlock(&rnp->lock);                /* irqs remain disabled. */
-        spin_unlock_irqrestore(&rsp->onofflock, flags);
+        raw_spin_unlock(&rnp->lock);            /* irqs remain disabled. */
+        raw_spin_unlock_irqrestore(&rsp->onofflock, flags);
 }
 
 /*
@@ -776,14 +798,14 @@ rcu_report_qs_rnp(unsigned long mask, struct rcu_state *rsp,
                 if (!(rnp->qsmask & mask)) {
 
                         /* Our bit has already been cleared, so done. */
-                        spin_unlock_irqrestore(&rnp->lock, flags);
+                        raw_spin_unlock_irqrestore(&rnp->lock, flags);
                         return;
                 }
                 rnp->qsmask &= ~mask;
                 if (rnp->qsmask != 0 || rcu_preempted_readers(rnp)) {
 
                         /* Other bits still set at this level, so done. */
-                        spin_unlock_irqrestore(&rnp->lock, flags);
+                        raw_spin_unlock_irqrestore(&rnp->lock, flags);
                         return;
                 }
                 mask = rnp->grpmask;
@@ -793,10 +815,10 @@ rcu_report_qs_rnp(unsigned long mask, struct rcu_state *rsp,
 
                         break;
                 }
-                spin_unlock_irqrestore(&rnp->lock, flags);
+                raw_spin_unlock_irqrestore(&rnp->lock, flags);
                 rnp_c = rnp;
                 rnp = rnp->parent;
-                spin_lock_irqsave(&rnp->lock, flags);
+                raw_spin_lock_irqsave(&rnp->lock, flags);
                 WARN_ON_ONCE(rnp_c->qsmask);
         }
 
@@ -825,7 +847,7 @@ rcu_report_qs_rdp(int cpu, struct rcu_state *rsp, struct rcu_data *rdp, long las
         struct rcu_node *rnp;
 
         rnp = rdp->mynode;
-        spin_lock_irqsave(&rnp->lock, flags);
+        raw_spin_lock_irqsave(&rnp->lock, flags);
         if (lastcomp != rnp->completed) {
 
                 /*
@@ -837,12 +859,12 @@ rcu_report_qs_rdp(int cpu, struct rcu_state *rsp, struct rcu_data *rdp, long las
                  * race occurred.
                  */
                 rdp->passed_quiesc = 0; /* try again later! */
-                spin_unlock_irqrestore(&rnp->lock, flags);
+                raw_spin_unlock_irqrestore(&rnp->lock, flags);
                 return;
         }
         mask = rdp->grpmask;
         if ((rnp->qsmask & mask) == 0) {
-                spin_unlock_irqrestore(&rnp->lock, flags);
+                raw_spin_unlock_irqrestore(&rnp->lock, flags);
         } else {
                 rdp->qs_pending = 0;
 
@@ -906,7 +928,7 @@ static void rcu_send_cbs_to_orphanage(struct rcu_state *rsp)
 
         if (rdp->nxtlist == NULL)
                 return;  /* irqs disabled, so comparison is stable. */
-        spin_lock(&rsp->onofflock);  /* irqs already disabled. */
+        raw_spin_lock(&rsp->onofflock);  /* irqs already disabled. */
         *rsp->orphan_cbs_tail = rdp->nxtlist;
         rsp->orphan_cbs_tail = rdp->nxttail[RCU_NEXT_TAIL];
         rdp->nxtlist = NULL;
@@ -914,7 +936,7 @@ static void rcu_send_cbs_to_orphanage(struct rcu_state *rsp)
                 rdp->nxttail[i] = &rdp->nxtlist;
         rsp->orphan_qlen += rdp->qlen;
         rdp->qlen = 0;
-        spin_unlock(&rsp->onofflock);  /* irqs remain disabled. */
+        raw_spin_unlock(&rsp->onofflock);  /* irqs remain disabled. */
 }
 
 /*
@@ -925,10 +947,10 @@ static void rcu_adopt_orphan_cbs(struct rcu_state *rsp)
         unsigned long flags;
         struct rcu_data *rdp;
 
-        spin_lock_irqsave(&rsp->onofflock, flags);
+        raw_spin_lock_irqsave(&rsp->onofflock, flags);
         rdp = rsp->rda[smp_processor_id()];
         if (rsp->orphan_cbs_list == NULL) {
-                spin_unlock_irqrestore(&rsp->onofflock, flags);
+                raw_spin_unlock_irqrestore(&rsp->onofflock, flags);
                 return;
         }
         *rdp->nxttail[RCU_NEXT_TAIL] = rsp->orphan_cbs_list;
@@ -937,7 +959,7 @@ static void rcu_adopt_orphan_cbs(struct rcu_state *rsp)
         rsp->orphan_cbs_list = NULL;
         rsp->orphan_cbs_tail = &rsp->orphan_cbs_list;
         rsp->orphan_qlen = 0;
-        spin_unlock_irqrestore(&rsp->onofflock, flags);
+        raw_spin_unlock_irqrestore(&rsp->onofflock, flags);
 }
 
 /*
@@ -953,23 +975,23 @@ static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp)
         struct rcu_node *rnp;
 
         /* Exclude any attempts to start a new grace period. */
-        spin_lock_irqsave(&rsp->onofflock, flags);
+        raw_spin_lock_irqsave(&rsp->onofflock, flags);
 
         /* Remove the outgoing CPU from the masks in the rcu_node hierarchy. */
         rnp = rdp->mynode;      /* this is the outgoing CPU's rnp. */
         mask = rdp->grpmask;    /* rnp->grplo is constant. */
         do {
-                spin_lock(&rnp->lock);          /* irqs already disabled. */
+                raw_spin_lock(&rnp->lock);      /* irqs already disabled. */
                 rnp->qsmaskinit &= ~mask;
                 if (rnp->qsmaskinit != 0) {
                         if (rnp != rdp->mynode)
-                                spin_unlock(&rnp->lock); /* irqs remain disabled. */
+                                raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */
                         break;
                 }
                 if (rnp == rdp->mynode)
                         need_report = rcu_preempt_offline_tasks(rsp, rnp, rdp);
                 else
-                        spin_unlock(&rnp->lock); /* irqs remain disabled. */
+                        raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */
                 mask = rnp->grpmask;
                 rnp = rnp->parent;
         } while (rnp != NULL);
@@ -980,12 +1002,12 @@ static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp)
          * because invoking rcu_report_unblock_qs_rnp() with ->onofflock
          * held leads to deadlock.
          */
-        spin_unlock(&rsp->onofflock); /* irqs remain disabled. */
+        raw_spin_unlock(&rsp->onofflock); /* irqs remain disabled. */
         rnp = rdp->mynode;
         if (need_report & RCU_OFL_TASKS_NORM_GP)
                 rcu_report_unblock_qs_rnp(rnp, flags);
         else
-                spin_unlock_irqrestore(&rnp->lock, flags);
+                raw_spin_unlock_irqrestore(&rnp->lock, flags);
         if (need_report & RCU_OFL_TASKS_EXP_GP)
                 rcu_report_exp_rnp(rsp, rnp);
 
@@ -1144,11 +1166,9 @@ void rcu_check_callbacks(int cpu, int user)
 /*
  * Scan the leaf rcu_node structures, processing dyntick state for any that
  * have not yet encountered a quiescent state, using the function specified.
- * Returns 1 if the current grace period ends while scanning (possibly
- * because we made it end).
+ * The caller must have suppressed start of new grace periods.
  */
-static int rcu_process_dyntick(struct rcu_state *rsp, long lastcomp,
-                               int (*f)(struct rcu_data *))
+static void force_qs_rnp(struct rcu_state *rsp, int (*f)(struct rcu_data *))
 {
         unsigned long bit;
         int cpu;
@@ -1158,13 +1178,13 @@ static int rcu_process_dyntick(struct rcu_state *rsp, long lastcomp,
 
         rcu_for_each_leaf_node(rsp, rnp) {
                 mask = 0;
-                spin_lock_irqsave(&rnp->lock, flags);
-                if (rnp->completed != lastcomp) {
-                        spin_unlock_irqrestore(&rnp->lock, flags);
-                        return 1;
+                raw_spin_lock_irqsave(&rnp->lock, flags);
+                if (!rcu_gp_in_progress(rsp)) {
+                        raw_spin_unlock_irqrestore(&rnp->lock, flags);
+                        return;
                 }
                 if (rnp->qsmask == 0) {
-                        spin_unlock_irqrestore(&rnp->lock, flags);
+                        raw_spin_unlock_irqrestore(&rnp->lock, flags);
                         continue;
                 }
                 cpu = rnp->grplo;
@@ -1173,15 +1193,14 @@ static int rcu_process_dyntick(struct rcu_state *rsp, long lastcomp,
                         if ((rnp->qsmask & bit) != 0 && f(rsp->rda[cpu]))
                                 mask |= bit;
                 }
-                if (mask != 0 && rnp->completed == lastcomp) {
+                if (mask != 0) {
 
                         /* rcu_report_qs_rnp() releases rnp->lock. */
                         rcu_report_qs_rnp(mask, rsp, rnp, flags);
                         continue;
                 }
-                spin_unlock_irqrestore(&rnp->lock, flags);
+                raw_spin_unlock_irqrestore(&rnp->lock, flags);
         }
-        return 0;
 }
 
 /*
@@ -1191,32 +1210,26 @@ static int rcu_process_dyntick(struct rcu_state *rsp, long lastcomp,
 static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
 {
         unsigned long flags;
-        long lastcomp;
         struct rcu_node *rnp = rcu_get_root(rsp);
-        u8 signaled;
-        u8 forcenow;
 
         if (!rcu_gp_in_progress(rsp))
                 return;  /* No grace period in progress, nothing to force. */
-        if (!spin_trylock_irqsave(&rsp->fqslock, flags)) {
+        if (!raw_spin_trylock_irqsave(&rsp->fqslock, flags)) {
                 rsp->n_force_qs_lh++; /* Inexact, can lose counts.  Tough! */
                 return; /* Someone else is already on the job. */
         }
-        if (relaxed &&
-            (long)(rsp->jiffies_force_qs - jiffies) >= 0)
-                goto unlock_ret; /* no emergency and done recently. */
+        if (relaxed && ULONG_CMP_GE(rsp->jiffies_force_qs, jiffies))
+                goto unlock_fqs_ret; /* no emergency and done recently. */
         rsp->n_force_qs++;
-        spin_lock(&rnp->lock);
-        lastcomp = rsp->gpnum - 1;
-        signaled = rsp->signaled;
+        raw_spin_lock(&rnp->lock);  /* irqs already disabled */
         rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS;
         if(!rcu_gp_in_progress(rsp)) {
                 rsp->n_force_qs_ngp++;
-                spin_unlock(&rnp->lock);
-                goto unlock_ret;  /* no GP in progress, time updated. */
+                raw_spin_unlock(&rnp->lock);  /* irqs remain disabled */
+                goto unlock_fqs_ret;  /* no GP in progress, time updated. */
         }
-        spin_unlock(&rnp->lock);
-        switch (signaled) {
+        rsp->fqs_active = 1;
+        switch (rsp->signaled) {
         case RCU_GP_IDLE:
         case RCU_GP_INIT:
 
@@ -1224,45 +1237,38 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
 
         case RCU_SAVE_DYNTICK:
 
+                raw_spin_unlock(&rnp->lock);  /* irqs remain disabled */
                 if (RCU_SIGNAL_INIT != RCU_SAVE_DYNTICK)
                         break; /* So gcc recognizes the dead code. */
 
                 /* Record dyntick-idle state. */
-                if (rcu_process_dyntick(rsp, lastcomp,
-                                        dyntick_save_progress_counter))
-                        goto unlock_ret;
-                /* fall into next case. */
-
-        case RCU_SAVE_COMPLETED:
-
-                /* Update state, record completion counter. */
-                forcenow = 0;
-                spin_lock(&rnp->lock);
-                if (lastcomp + 1 == rsp->gpnum &&
-                    lastcomp == rsp->completed &&
-                    rsp->signaled == signaled) {
+                force_qs_rnp(rsp, dyntick_save_progress_counter);
+                raw_spin_lock(&rnp->lock);  /* irqs already disabled */
+                if (rcu_gp_in_progress(rsp))
                         rsp->signaled = RCU_FORCE_QS;
-                        rsp->completed_fqs = lastcomp;
-                        forcenow = signaled == RCU_SAVE_COMPLETED;
-                }
-                spin_unlock(&rnp->lock);
-                if (!forcenow)
-                        break;
-                /* fall into next case. */
+                break;
 
         case RCU_FORCE_QS:
 
                 /* Check dyntick-idle state, send IPI to laggarts. */
-                if (rcu_process_dyntick(rsp, rsp->completed_fqs,
-                                        rcu_implicit_dynticks_qs))
-                        goto unlock_ret;
+                raw_spin_unlock(&rnp->lock);  /* irqs remain disabled */
+                force_qs_rnp(rsp, rcu_implicit_dynticks_qs);
 
                 /* Leave state in case more forcing is required. */
 
+                raw_spin_lock(&rnp->lock);  /* irqs already disabled */
                 break;
         }
-unlock_ret:
-        spin_unlock_irqrestore(&rsp->fqslock, flags);
+        rsp->fqs_active = 0;
+        if (rsp->fqs_need_gp) {
+                raw_spin_unlock(&rsp->fqslock); /* irqs remain disabled */
+                rsp->fqs_need_gp = 0;
+                rcu_start_gp(rsp, flags); /* releases rnp->lock */
+                return;
+        }
+        raw_spin_unlock(&rnp->lock);  /* irqs remain disabled */
+unlock_fqs_ret:
+        raw_spin_unlock_irqrestore(&rsp->fqslock, flags);
 }
 
 #else /* #ifdef CONFIG_SMP */
@@ -1290,7 +1296,7 @@ __rcu_process_callbacks(struct rcu_state *rsp, struct rcu_data *rdp)
          * If an RCU GP has gone long enough, go check for dyntick
          * idle CPUs and, if needed, send resched IPIs.
          */
-        if ((long)(ACCESS_ONCE(rsp->jiffies_force_qs) - jiffies) < 0)
+        if (ULONG_CMP_LT(ACCESS_ONCE(rsp->jiffies_force_qs), jiffies))
                 force_quiescent_state(rsp, 1);
 
         /*
@@ -1304,7 +1310,7 @@ __rcu_process_callbacks(struct rcu_state *rsp, struct rcu_data *rdp)
 
         /* Does this CPU require a not-yet-started grace period? */
         if (cpu_needs_another_gp(rsp, rdp)) {
-                spin_lock_irqsave(&rcu_get_root(rsp)->lock, flags);
+                raw_spin_lock_irqsave(&rcu_get_root(rsp)->lock, flags);
                 rcu_start_gp(rsp, flags);  /* releases above lock */
         }
 
@@ -1335,6 +1341,9 @@ static void rcu_process_callbacks(struct softirq_action *unused)
          * grace-period manipulations above.
          */
         smp_mb(); /* See above block comment. */
+
+        /* If we are last CPU on way to dyntick-idle mode, accelerate it. */
+        rcu_needs_cpu_flush();
 }
 
 static void
@@ -1369,7 +1378,7 @@ __call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu),
                 unsigned long nestflag;
                 struct rcu_node *rnp_root = rcu_get_root(rsp);
 
-                spin_lock_irqsave(&rnp_root->lock, nestflag);
+                raw_spin_lock_irqsave(&rnp_root->lock, nestflag);
                 rcu_start_gp(rsp, nestflag);  /* releases rnp_root->lock. */
         }
 
@@ -1387,7 +1396,7 @@ __call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu),
                         force_quiescent_state(rsp, 0);
                 rdp->n_force_qs_snap = rsp->n_force_qs;
                 rdp->qlen_last_fqs_check = rdp->qlen;
-        } else if ((long)(ACCESS_ONCE(rsp->jiffies_force_qs) - jiffies) < 0)
+        } else if (ULONG_CMP_LT(ACCESS_ONCE(rsp->jiffies_force_qs), jiffies))
                 force_quiescent_state(rsp, 1);
         local_irq_restore(flags);
 }
@@ -1520,7 +1529,7 @@ static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp)
 
         /* Has an RCU GP gone long enough to send resched IPIs &c? */
         if (rcu_gp_in_progress(rsp) &&
-            ((long)(ACCESS_ONCE(rsp->jiffies_force_qs) - jiffies) < 0)) {
+            ULONG_CMP_LT(ACCESS_ONCE(rsp->jiffies_force_qs), jiffies)) {
                 rdp->n_rp_need_fqs++;
                 return 1;
         }
@@ -1545,10 +1554,9 @@ static int rcu_pending(int cpu)
 /*
  * Check to see if any future RCU-related work will need to be done
  * by the current CPU, even if none need be done immediately, returning
- * 1 if so.  This function is part of the RCU implementation; it is -not-
- * an exported member of the RCU API.
+ * 1 if so.
  */
-int rcu_needs_cpu(int cpu)
+static int rcu_needs_cpu_quick_check(int cpu)
 {
         /* RCU callbacks either ready or pending? */
         return per_cpu(rcu_sched_data, cpu).nxtlist ||
@@ -1556,21 +1564,6 @@ int rcu_needs_cpu(int cpu)
                rcu_preempt_needs_cpu(cpu);
 }
 
-/*
- * This function is invoked towards the end of the scheduler's initialization
- * process.  Before this is called, the idle task might contain
- * RCU read-side critical sections (during which time, this idle
- * task is booting the system).  After this function is called, the
- * idle tasks are prohibited from containing RCU read-side critical
- * sections.
- */
-void rcu_scheduler_starting(void)
-{
-        WARN_ON(num_online_cpus() != 1);
-        WARN_ON(nr_context_switches() > 0);
-        rcu_scheduler_active = 1;
-}
-
 static DEFINE_PER_CPU(struct rcu_head, rcu_barrier_head) = {NULL};
 static atomic_t rcu_barrier_cpu_count;
 static DEFINE_MUTEX(rcu_barrier_mutex);
@@ -1659,7 +1652,7 @@ rcu_boot_init_percpu_data(int cpu, struct rcu_state *rsp)
         struct rcu_node *rnp = rcu_get_root(rsp);
 
         /* Set up local state, ensuring consistent view of global state. */
-        spin_lock_irqsave(&rnp->lock, flags);
+        raw_spin_lock_irqsave(&rnp->lock, flags);
         rdp->grpmask = 1UL << (cpu - rdp->mynode->grplo);
         rdp->nxtlist = NULL;
         for (i = 0; i < RCU_NEXT_SIZE; i++)
@@ -1669,7 +1662,7 @@ rcu_boot_init_percpu_data(int cpu, struct rcu_state *rsp)
         rdp->dynticks = &per_cpu(rcu_dynticks, cpu);
 #endif /* #ifdef CONFIG_NO_HZ */
         rdp->cpu = cpu;
-        spin_unlock_irqrestore(&rnp->lock, flags);
+        raw_spin_unlock_irqrestore(&rnp->lock, flags);
 }
 
 /*
@@ -1687,7 +1680,7 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp, int preemptable)
         struct rcu_node *rnp = rcu_get_root(rsp);
 
         /* Set up local state, ensuring consistent view of global state. */
-        spin_lock_irqsave(&rnp->lock, flags);
+        raw_spin_lock_irqsave(&rnp->lock, flags);
         rdp->passed_quiesc = 0;  /* We could be racing with new GP, */
         rdp->qs_pending = 1;     /*  so set up to respond to current GP. */
         rdp->beenonline = 1;     /* We have now been online. */
@@ -1695,7 +1688,7 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp, int preemptable)
         rdp->qlen_last_fqs_check = 0;
         rdp->n_force_qs_snap = rsp->n_force_qs;
         rdp->blimit = blimit;
-        spin_unlock(&rnp->lock);                /* irqs remain disabled. */
+        raw_spin_unlock(&rnp->lock);            /* irqs remain disabled. */
 
         /*
          * A new grace period might start here.  If so, we won't be part
@@ -1703,14 +1696,14 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp, int preemptable)
          */
 
         /* Exclude any attempts to start a new GP on large systems. */
-        spin_lock(&rsp->onofflock);             /* irqs already disabled. */
+        raw_spin_lock(&rsp->onofflock);         /* irqs already disabled. */
 
         /* Add CPU to rcu_node bitmasks. */
         rnp = rdp->mynode;
         mask = rdp->grpmask;
         do {
                 /* Exclude any attempts to start a new GP on small systems. */
-                spin_lock(&rnp->lock);  /* irqs already disabled. */
+                raw_spin_lock(&rnp->lock);      /* irqs already disabled. */
                 rnp->qsmaskinit |= mask;
                 mask = rnp->grpmask;
                 if (rnp == rdp->mynode) {
@@ -1718,11 +1711,11 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp, int preemptable)
                         rdp->completed = rnp->completed;
                         rdp->passed_quiesc_completed = rnp->completed - 1;
                 }
-                spin_unlock(&rnp->lock); /* irqs already disabled. */
+                raw_spin_unlock(&rnp->lock); /* irqs already disabled. */
                 rnp = rnp->parent;
         } while (rnp != NULL && !(rnp->qsmaskinit & mask));
 
-        spin_unlock_irqrestore(&rsp->onofflock, flags);
+        raw_spin_unlock_irqrestore(&rsp->onofflock, flags);
 }
 
 static void __cpuinit rcu_online_cpu(int cpu)
@@ -1806,11 +1799,17 @@ static void __init rcu_init_levelspread(struct rcu_state *rsp)
  */
 static void __init rcu_init_one(struct rcu_state *rsp)
 {
+        static char *buf[] = { "rcu_node_level_0",
+                               "rcu_node_level_1",
+                               "rcu_node_level_2",
+                               "rcu_node_level_3" };  /* Match MAX_RCU_LVLS */
         int cpustride = 1;
         int i;
         int j;
         struct rcu_node *rnp;
 
+        BUILD_BUG_ON(MAX_RCU_LVLS > ARRAY_SIZE(buf));  /* Fix buf[] init! */
+
         /* Initialize the level-tracking arrays. */
 
         for (i = 1; i < NUM_RCU_LVLS; i++)
@@ -1823,8 +1822,9 @@ static void __init rcu_init_one(struct rcu_state *rsp)
                 cpustride *= rsp->levelspread[i];
                 rnp = rsp->level[i];
                 for (j = 0; j < rsp->levelcnt[i]; j++, rnp++) {
-                        spin_lock_init(&rnp->lock);
-                        lockdep_set_class(&rnp->lock, &rcu_node_class[i]);
+                        raw_spin_lock_init(&rnp->lock);
+                        lockdep_set_class_and_name(&rnp->lock,
+                                                   &rcu_node_class[i], buf[i]);
                         rnp->gpnum = 0;
                         rnp->qsmask = 0;
                         rnp->qsmaskinit = 0;
@@ -1876,7 +1876,7 @@ do { \
 
 void __init rcu_init(void)
 {
-        int i;
+        int cpu;
 
         rcu_bootup_announce();
 #ifdef CONFIG_RCU_CPU_STALL_DETECTOR
@@ -1896,8 +1896,8 @@ void __init rcu_init(void)
          * or the scheduler are operational.
          */
         cpu_notifier(rcu_cpu_notify, 0);
-        for_each_online_cpu(i)
-                rcu_cpu_notify(NULL, CPU_UP_PREPARE, (void *)(long)i);
+        for_each_online_cpu(cpu)
+                rcu_cpu_notify(NULL, CPU_UP_PREPARE, (void *)(long)cpu);
 }
 
 #include "rcutree_plugin.h"