USB: retain USB device power/wakeup setting across reconfiguration
[pandora-kernel.git] / kernel / rcutree.c
index 53ae959..3ec8160 100644 (file)
@@ -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
@@ -156,6 +152,24 @@ 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?
  */
@@ -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"