[PATCH 7/7] x86/mcheck: Move CPU_DEAD to hotplug state machine

[Sebastian Andrzej Siewior]

This moves the last piece of the old hotplug notifier code in MCE to the
new hotplug state machine.

Cc: Tony Luck <tony.l...@intel.com>
Cc: Borislav Petkov <b...@alien8.de>
Cc: linux-e...@vger.kernel.org
Cc: x...@kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bige...@linutronix.de>
---
 arch/x86/kernel/cpu/mcheck/mce.c | 42 ++++++++++++++--------------------------
 include/linux/cpuhotplug.h       |  1 +
 2 files changed, 16 insertions(+), 27 deletions(-)

diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 444177cafb65..d31e3a7d8866 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -2501,26 +2501,14 @@ static void mce_reenable_cpu(void)
        }
 }
 
-/* Get notified when a cpu comes on/off. Be hotplug friendly. */
-static int
-mce_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
+static int mce_cpu_dead(unsigned int cpu)
 {
-       unsigned int cpu = (unsigned long)hcpu;
+       mce_intel_hcpu_update(cpu);
 
-       switch (action & ~CPU_TASKS_FROZEN) {
-       case CPU_DEAD:
-               mce_intel_hcpu_update(cpu);
-
-               /* intentionally ignoring frozen here */
-               if (!(action & CPU_TASKS_FROZEN))
-                       cmci_rediscover();
-               break;
-       case CPU_DOWN_PREPARE:
-
-               break;
-       }
-
-       return NOTIFY_OK;
+       /* intentionally ignoring frozen here */
+       if (!cpuhp_tasks_frozen)
+               cmci_rediscover();
+       return 0;
 }
 
 static int mce_cpu_online(unsigned int cpu)
@@ -2551,10 +2539,6 @@ static int mce_cpu_pre_down(unsigned int cpu)
        return 0;
 }
 
-static struct notifier_block mce_cpu_notifier = {
-       .notifier_call = mce_cpu_callback,
-};
-
 static __init void mce_init_banks(void)
 {
        int i;
@@ -2594,16 +2578,17 @@ static __init int mcheck_init_device(void)
        if (err)
                goto err_out_mem;
 
+       err = cpuhp_setup_state(CPUHP_X86_MCE_DEAD, "x86/mce:dead", NULL,
+                               mce_cpu_dead);
+       if (err)
+               goto err_out_mem;
+
        err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/mce:online",
                                mce_cpu_online, mce_cpu_pre_down);
        if (err < 0)
-               goto err_out_mem;
+               goto err_out_online;
        hp_online = err;
 
-       cpu_notifier_register_begin();
-       __register_hotcpu_notifier(&mce_cpu_notifier);
-       cpu_notifier_register_done();
-
        register_syscore_ops(&mce_syscore_ops);
 
        /* register character device /dev/mcelog */
@@ -2617,6 +2602,9 @@ static __init int mcheck_init_device(void)
        unregister_syscore_ops(&mce_syscore_ops);
        cpuhp_remove_state(hp_online);
 
+err_out_online:
+       cpuhp_remove_state(CPUHP_X86_MCE_DEAD);
+
 err_out_mem:
        free_cpumask_var(mce_device_initialized);
 
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 3410d83cc2e2..79b96f647d64 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -16,6 +16,7 @@ enum cpuhp_state {
        CPUHP_PERF_SUPERH,
        CPUHP_X86_HPET_DEAD,
        CPUHP_X86_APB_DEAD,
+       CPUHP_X86_MCE_DEAD,
        CPUHP_VIRT_NET_DEAD,
        CPUHP_SLUB_DEAD,
        CPUHP_MM_WRITEBACK_DEAD,
-- 
2.10.2