Add suspend-related notifications for CPU hotplug

Since nonboot CPUs are now disabled after tasks and devices have been
frozen and the CPU hotplug infrastructure is used for this purpose, we need
special CPU hotplug notifications that will help the CPU-hotplug-aware
subsystems distinguish normal CPU hotplug events from CPU hotplug events
related to a system-wide suspend or resume operation in progress.  This
patch introduces such notifications and causes them to be used during
suspend and resume transitions.  It also changes all of the
CPU-hotplug-aware subsystems to take these notifications into consideration
(for now they are handled in the same way as the corresponding "normal"
ones).

[oleg@tv-sign.ru: cleanups]
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 18 insertions, 16 deletions

diff --git a/kernel/cpu.c b/kernel/cpu.c
index 28cb6c71a47a..369d2892687d 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -120,12 +120,13 @@ static int take_cpu_down(void *unused)
 }
 
 /* Requires cpu_add_remove_lock to be held */
-static int _cpu_down(unsigned int cpu)
+static int _cpu_down(unsigned int cpu, int tasks_frozen)
 {
         int err, nr_calls = 0;
         struct task_struct *p;
         cpumask_t old_allowed, tmp;
         void *hcpu = (void *)(long)cpu;
+        unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0;
 
         if (num_online_cpus() == 1)
                 return -EBUSY;
@@ -134,11 +135,11 @@ static int _cpu_down(unsigned int cpu)
                 return -EINVAL;
 
         raw_notifier_call_chain(&cpu_chain, CPU_LOCK_ACQUIRE, hcpu);
-        err = __raw_notifier_call_chain(&cpu_chain, CPU_DOWN_PREPARE,
+        err = __raw_notifier_call_chain(&cpu_chain, CPU_DOWN_PREPARE | mod,
                                         hcpu, -1, &nr_calls);
         if (err == NOTIFY_BAD) {
-                __raw_notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED, hcpu,
-                                          nr_calls, NULL);
+                __raw_notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED | mod,
+                                          hcpu, nr_calls, NULL);
                 printk("%s: attempt to take down CPU %u failed\n",
                                 __FUNCTION__, cpu);
                 err = -EINVAL;
@@ -157,7 +158,7 @@ static int _cpu_down(unsigned int cpu)
 
         if (IS_ERR(p) || cpu_online(cpu)) {
                 /* CPU didn't die: tell everyone.  Can't complain. */
-                if (raw_notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED,
+                if (raw_notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED | mod,
                                             hcpu) == NOTIFY_BAD)
                         BUG();
 
@@ -176,7 +177,8 @@ static int _cpu_down(unsigned int cpu)
         __cpu_die(cpu);
 
         /* CPU is completely dead: tell everyone.  Too late to complain. */
-        if (raw_notifier_call_chain(&cpu_chain, CPU_DEAD, hcpu) == NOTIFY_BAD)
+        if (raw_notifier_call_chain(&cpu_chain, CPU_DEAD | mod,
+                                    hcpu) == NOTIFY_BAD)
                 BUG();
 
         check_for_tasks(cpu);
@@ -186,8 +188,7 @@ out_thread:
 out_allowed:
         set_cpus_allowed(current, old_allowed);
 out_release:
-        raw_notifier_call_chain(&cpu_chain, CPU_LOCK_RELEASE,
-                                                (void *)(long)cpu);
+        raw_notifier_call_chain(&cpu_chain, CPU_LOCK_RELEASE, hcpu);
         return err;
 }
 
@@ -199,7 +200,7 @@ int cpu_down(unsigned int cpu)
         if (cpu_hotplug_disabled)
                 err = -EBUSY;
         else
-                err = _cpu_down(cpu);
+                err = _cpu_down(cpu, 0);
 
         mutex_unlock(&cpu_add_remove_lock);
         return err;
@@ -207,16 +208,17 @@ int cpu_down(unsigned int cpu)
 #endif /*CONFIG_HOTPLUG_CPU*/
 
 /* Requires cpu_add_remove_lock to be held */
-static int __cpuinit _cpu_up(unsigned int cpu)
+static int __cpuinit _cpu_up(unsigned int cpu, int tasks_frozen)
 {
         int ret, nr_calls = 0;
         void *hcpu = (void *)(long)cpu;
+        unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0;
 
         if (cpu_online(cpu) || !cpu_present(cpu))
                 return -EINVAL;
 
         raw_notifier_call_chain(&cpu_chain, CPU_LOCK_ACQUIRE, hcpu);
-        ret = __raw_notifier_call_chain(&cpu_chain, CPU_UP_PREPARE, hcpu,
+        ret = __raw_notifier_call_chain(&cpu_chain, CPU_UP_PREPARE | mod, hcpu,
                                                         -1, &nr_calls);
         if (ret == NOTIFY_BAD) {
                 printk("%s: attempt to bring up CPU %u failed\n",
@@ -234,12 +236,12 @@ static int __cpuinit _cpu_up(unsigned int cpu)
         BUG_ON(!cpu_online(cpu));
 
         /* Now call notifier in preparation. */
-        raw_notifier_call_chain(&cpu_chain, CPU_ONLINE, hcpu);
+        raw_notifier_call_chain(&cpu_chain, CPU_ONLINE | mod, hcpu);
 
 out_notify:
         if (ret != 0)
                 __raw_notifier_call_chain(&cpu_chain,
-                                CPU_UP_CANCELED, hcpu, nr_calls, NULL);
+                                CPU_UP_CANCELED | mod, hcpu, nr_calls, NULL);
         raw_notifier_call_chain(&cpu_chain, CPU_LOCK_RELEASE, hcpu);
 
         return ret;
@@ -253,7 +255,7 @@ int __cpuinit cpu_up(unsigned int cpu)
         if (cpu_hotplug_disabled)
                 err = -EBUSY;
         else
-                err = _cpu_up(cpu);
+                err = _cpu_up(cpu, 0);
 
         mutex_unlock(&cpu_add_remove_lock);
         return err;
@@ -283,7 +285,7 @@ int disable_nonboot_cpus(void)
         for_each_online_cpu(cpu) {
                 if (cpu == first_cpu)
                         continue;
-                error = _cpu_down(cpu);
+                error = _cpu_down(cpu, 1);
                 if (!error) {
                         cpu_set(cpu, frozen_cpus);
                         printk("CPU%d is down\n", cpu);
@@ -318,7 +320,7 @@ void enable_nonboot_cpus(void)
         suspend_cpu_hotplug = 1;
         printk("Enabling non-boot CPUs ...\n");
         for_each_cpu_mask(cpu, frozen_cpus) {
-                error = _cpu_up(cpu);
+                error = _cpu_up(cpu, 1);
                 if (!error) {
                         printk("CPU%d is up\n", cpu);
                         continue;