ia64/salinfo: Convert to hotplug state machine

Install the callbacks via the state machine and let the core invoke
the callbacks on the already online CPUs.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-ia64@vger.kernel.org
Cc: kbuild test robot <lkp@intel.com>
Cc: rt@linutronix.de
Cc: kbuild-all@01.org
Link: http://lkml.kernel.org/r/20161103173128.xuulg4nius46dng5@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/arch/ia64/kernel/salinfo.c b/arch/ia64/kernel/salinfo.c
index 5313007d5423a23622192f00218399806b421844..aaf74f36cfa1cd9dd2334c7fc4a0d331ad00649f 100644 (file)
--- a/arch/ia64/kernel/salinfo.c
+++ b/arch/ia64/kernel/salinfo.c
@@ -550,52 +550,40 @@ static const struct file_operations salinfo_data_fops = {
        .llseek  = default_llseek,
 };
 
-static int
-salinfo_cpu_callback(struct notifier_block *nb, unsigned long action, void *hcpu)
+static int salinfo_cpu_online(unsigned int cpu)
 {
-       unsigned int i, cpu = (unsigned long)hcpu;
-       unsigned long flags;
+       unsigned int i, end = ARRAY_SIZE(salinfo_data);
        struct salinfo_data *data;
-       switch (action) {
-       case CPU_ONLINE:
-       case CPU_ONLINE_FROZEN:
-               spin_lock_irqsave(&data_saved_lock, flags);
-               for (i = 0, data = salinfo_data;
-                    i < ARRAY_SIZE(salinfo_data);
-                    ++i, ++data) {
-                       cpumask_set_cpu(cpu, &data->cpu_event);
-                       wake_up_interruptible(&data->read_wait);
-               }
-               spin_unlock_irqrestore(&data_saved_lock, flags);
-               break;
-       case CPU_DEAD:
-       case CPU_DEAD_FROZEN:
-               spin_lock_irqsave(&data_saved_lock, flags);
-               for (i = 0, data = salinfo_data;
-                    i < ARRAY_SIZE(salinfo_data);
-                    ++i, ++data) {
-                       struct salinfo_data_saved *data_saved;
-                       int j;
-                       for (j = ARRAY_SIZE(data->data_saved) - 1, data_saved = data->data_saved + j;
-                            j >= 0;
-                            --j, --data_saved) {
-                               if (data_saved->buffer && data_saved->cpu == cpu) {
-                                       shift1_data_saved(data, j);
-                               }
-                       }
-                       cpumask_clear_cpu(cpu, &data->cpu_event);
-               }
-               spin_unlock_irqrestore(&data_saved_lock, flags);
-               break;
+
+       spin_lock_irq(&data_saved_lock);
+       for (i = 0, data = salinfo_data; i < end; ++i, ++data) {
+               cpumask_set_cpu(cpu, &data->cpu_event);
+               wake_up_interruptible(&data->read_wait);
        }
-       return NOTIFY_OK;
+       spin_unlock_irq(&data_saved_lock);
+       return 0;
 }
 
-static struct notifier_block salinfo_cpu_notifier =
+static int salinfo_cpu_pre_down(unsigned int cpu)
 {
-       .notifier_call = salinfo_cpu_callback,
-       .priority = 0,
-};
+       unsigned int i, end = ARRAY_SIZE(salinfo_data);
+       struct salinfo_data *data;
+
+       spin_lock_irq(&data_saved_lock);
+       for (i = 0, data = salinfo_data; i < end; ++i, ++data) {
+               struct salinfo_data_saved *data_saved;
+               int j = ARRAY_SIZE(data->data_saved) - 1;
+
+               for (data_saved = data->data_saved + j; j >= 0;
+                    --j, --data_saved) {
+                       if (data_saved->buffer && data_saved->cpu == cpu)
+                               shift1_data_saved(data, j);
+               }
+               cpumask_clear_cpu(cpu, &data->cpu_event);
+       }
+       spin_unlock_irq(&data_saved_lock);
+       return 0;
+}
 
 static int __init
 salinfo_init(void)
@@ -604,7 +592,7 @@ salinfo_init(void)
        struct proc_dir_entry **sdir = salinfo_proc_entries; /* keeps track of every entry */
        struct proc_dir_entry *dir, *entry;
        struct salinfo_data *data;
-       int i, j;
+       int i;
 
        salinfo_dir = proc_mkdir("sal", NULL);
        if (!salinfo_dir)
@@ -617,8 +605,6 @@ salinfo_init(void)
                                           (void *)salinfo_entries[i].feature);
        }
 
-       cpu_notifier_register_begin();
-
        for (i = 0; i < ARRAY_SIZE(salinfo_log_name); i++) {
                data = salinfo_data + i;
                data->type = i;
@@ -639,10 +625,6 @@ salinfo_init(void)
                        continue;
                *sdir++ = entry;
 
-               /* we missed any events before now */
-               for_each_online_cpu(j)
-                       cpumask_set_cpu(j, &data->cpu_event);
-
                *sdir++ = dir;
        }
 
@@ -653,10 +635,9 @@ salinfo_init(void)
        salinfo_timer.function = &salinfo_timeout;
        add_timer(&salinfo_timer);
 
-       __register_hotcpu_notifier(&salinfo_cpu_notifier);
-
-       cpu_notifier_register_done();
-
+       i = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "ia64/salinfo:online",
+                             salinfo_cpu_online, salinfo_cpu_pre_down);
+       WARN_ON(i < 0);
        return 0;
 }