5 files changed, 78 insertions, 100 deletions

diff --git a/kernel/cpu.c b/kernel/cpu.c
index 12b7458f23b1..aa39dd7a3846 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -15,6 +15,7 @@
 #include <linux/stop_machine.h>
 #include <linux/mutex.h>
 #include <linux/gfp.h>
+#include <linux/suspend.h>
 
 #ifdef CONFIG_SMP
 /* Serializes the updates to cpu_online_mask, cpu_present_mask */
@@ -476,6 +477,79 @@ static int alloc_frozen_cpus(void)
         return 0;
 }
 core_initcall(alloc_frozen_cpus);
+
+/*
+ * Prevent regular CPU hotplug from racing with the freezer, by disabling CPU
+ * hotplug when tasks are about to be frozen. Also, don't allow the freezer
+ * to continue until any currently running CPU hotplug operation gets
+ * completed.
+ * To modify the 'cpu_hotplug_disabled' flag, we need to acquire the
+ * 'cpu_add_remove_lock'. And this same lock is also taken by the regular
+ * CPU hotplug path and released only after it is complete. Thus, we
+ * (and hence the freezer) will block here until any currently running CPU
+ * hotplug operation gets completed.
+ */
+void cpu_hotplug_disable_before_freeze(void)
+{
+        cpu_maps_update_begin();
+        cpu_hotplug_disabled = 1;
+        cpu_maps_update_done();
+}
+
+
+/*
+ * When tasks have been thawed, re-enable regular CPU hotplug (which had been
+ * disabled while beginning to freeze tasks).
+ */
+void cpu_hotplug_enable_after_thaw(void)
+{
+        cpu_maps_update_begin();
+        cpu_hotplug_disabled = 0;
+        cpu_maps_update_done();
+}
+
+/*
+ * When callbacks for CPU hotplug notifications are being executed, we must
+ * ensure that the state of the system with respect to the tasks being frozen
+ * or not, as reported by the notification, remains unchanged *throughout the
+ * duration* of the execution of the callbacks.
+ * Hence we need to prevent the freezer from racing with regular CPU hotplug.
+ *
+ * This synchronization is implemented by mutually excluding regular CPU
+ * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/
+ * Hibernate notifications.
+ */
+static int
+cpu_hotplug_pm_callback(struct notifier_block *nb,
+                        unsigned long action, void *ptr)
+{
+        switch (action) {
+
+        case PM_SUSPEND_PREPARE:
+        case PM_HIBERNATION_PREPARE:
+                cpu_hotplug_disable_before_freeze();
+                break;
+
+        case PM_POST_SUSPEND:
+        case PM_POST_HIBERNATION:
+                cpu_hotplug_enable_after_thaw();
+                break;
+
+        default:
+                return NOTIFY_DONE;
+        }
+
+        return NOTIFY_OK;
+}
+
+
+int cpu_hotplug_pm_sync_init(void)
+{
+        pm_notifier(cpu_hotplug_pm_callback, 0);
+        return 0;
+}
+core_initcall(cpu_hotplug_pm_sync_init);
+
 #endif /* CONFIG_PM_SLEEP_SMP */
 
 /**
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 12a0287e0358..e1253faa34dd 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -29,7 +29,6 @@
 #include <linux/hardirq.h>
 #include <linux/rculist.h>
 #include <linux/uaccess.h>
-#include <linux/suspend.h>
 #include <linux/syscalls.h>
 #include <linux/anon_inodes.h>
 #include <linux/kernel_stat.h>
@@ -6853,7 +6852,7 @@ static void __cpuinit perf_event_init_cpu(int cpu)
         struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
 
         mutex_lock(&swhash->hlist_mutex);
-        if (swhash->hlist_refcount > 0 && !swhash->swevent_hlist) {
+        if (swhash->hlist_refcount > 0) {
                 struct swevent_hlist *hlist;
 
                 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
@@ -6942,14 +6941,7 @@ perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
 {
         unsigned int cpu = (long)hcpu;
 
-        /*
-         * Ignore suspend/resume action, the perf_pm_notifier will
-         * take care of that.
-         */
-        if (action & CPU_TASKS_FROZEN)
-                return NOTIFY_OK;
-
-        switch (action) {
+        switch (action & ~CPU_TASKS_FROZEN) {
 
         case CPU_UP_PREPARE:
         case CPU_DOWN_FAILED:
@@ -6968,90 +6960,6 @@ perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
         return NOTIFY_OK;
 }
 
-static void perf_pm_resume_cpu(void *unused)
-{
-        struct perf_cpu_context *cpuctx;
-        struct perf_event_context *ctx;
-        struct pmu *pmu;
-        int idx;
-
-        idx = srcu_read_lock(&pmus_srcu);
-        list_for_each_entry_rcu(pmu, &pmus, entry) {
-                cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
-                ctx = cpuctx->task_ctx;
-
-                perf_ctx_lock(cpuctx, ctx);
-                perf_pmu_disable(cpuctx->ctx.pmu);
-
-                cpu_ctx_sched_out(cpuctx, EVENT_ALL);
-                if (ctx)
-                        ctx_sched_out(ctx, cpuctx, EVENT_ALL);
-
-                perf_pmu_enable(cpuctx->ctx.pmu);
-                perf_ctx_unlock(cpuctx, ctx);
-        }
-        srcu_read_unlock(&pmus_srcu, idx);
-}
-
-static void perf_pm_suspend_cpu(void *unused)
-{
-        struct perf_cpu_context *cpuctx;
-        struct perf_event_context *ctx;
-        struct pmu *pmu;
-        int idx;
-
-        idx = srcu_read_lock(&pmus_srcu);
-        list_for_each_entry_rcu(pmu, &pmus, entry) {
-                cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
-                ctx = cpuctx->task_ctx;
-
-                perf_ctx_lock(cpuctx, ctx);
-                perf_pmu_disable(cpuctx->ctx.pmu);
-
-                perf_event_sched_in(cpuctx, ctx, current);
-
-                perf_pmu_enable(cpuctx->ctx.pmu);
-                perf_ctx_unlock(cpuctx, ctx);
-        }
-        srcu_read_unlock(&pmus_srcu, idx);
-}
-
-static int perf_resume(void)
-{
-        get_online_cpus();
-        smp_call_function(perf_pm_resume_cpu, NULL, 1);
-        put_online_cpus();
-
-        return NOTIFY_OK;
-}
-
-static int perf_suspend(void)
-{
-        get_online_cpus();
-        smp_call_function(perf_pm_suspend_cpu, NULL, 1);
-        put_online_cpus();
-
-        return NOTIFY_OK;
-}
-
-static int perf_pm(struct notifier_block *self, unsigned long action, void *ptr)
-{
-        switch (action) {
-        case PM_POST_HIBERNATION:
-        case PM_POST_SUSPEND:
-                return perf_resume();
-        case PM_HIBERNATION_PREPARE:
-        case PM_SUSPEND_PREPARE:
-                return perf_suspend();
-        default:
-                return NOTIFY_DONE;
-        }
-}
-
-static struct notifier_block perf_pm_notifier = {
-        .notifier_call = perf_pm,
-};
-
 void __init perf_event_init(void)
 {
         int ret;
@@ -7066,7 +6974,6 @@ void __init perf_event_init(void)
         perf_tp_register();
         perf_cpu_notifier(perf_cpu_notify);
         register_reboot_notifier(&perf_reboot_notifier);
-        register_pm_notifier(&perf_pm_notifier);
 
         ret = init_hw_breakpoint();
         WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
diff --git a/kernel/freezer.c b/kernel/freezer.c
index 66a594e8ad2f..7b01de98bb6a 100644
--- a/kernel/freezer.c
+++ b/kernel/freezer.c
@@ -67,7 +67,7 @@ static void fake_signal_wake_up(struct task_struct *p)
         unsigned long flags;
 
         spin_lock_irqsave(&p->sighand->siglock, flags);
-        signal_wake_up(p, 1);
+        signal_wake_up(p, 0);
         spin_unlock_irqrestore(&p->sighand->siglock, flags);
 }
 
diff --git a/kernel/power/qos.c b/kernel/power/qos.c
index 1c1797dd1d1d..5167d996cd02 100644
--- a/kernel/power/qos.c
+++ b/kernel/power/qos.c
@@ -386,8 +386,7 @@ static int pm_qos_power_open(struct inode *inode, struct file *filp)
                 pm_qos_add_request(req, pm_qos_class, PM_QOS_DEFAULT_VALUE);
                 filp->private_data = req;
 
-                if (filp->private_data)
-                        return 0;
+                return 0;
         }
         return -EPERM;
 }
diff --git a/kernel/sched.c b/kernel/sched.c
index d87c6e5d4e8c..0e9344a71be3 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -7087,8 +7087,6 @@ static int __init isolated_cpu_setup(char *str)
 
 __setup("isolcpus=", isolated_cpu_setup);
 
-#define SD_NODES_PER_DOMAIN 16
-
 #ifdef CONFIG_NUMA
 
 /**