releases/4.9.120/cpu-hotplug-non-smp-machines-do-not-make-use-of-booted_once.patch

From 269777aa530f3438ec1781586cdac0b5fe47b061 Mon Sep 17 00:00:00 2001
From: Abel Vesa <abelvesa@linux.com>
Date: Wed, 15 Aug 2018 00:26:00 +0300
Subject: cpu/hotplug: Non-SMP machines do not make use of booted_once

From: Abel Vesa <abelvesa@linux.com>

commit 269777aa530f3438ec1781586cdac0b5fe47b061 upstream.

Commit 0cc3cd21657b ("cpu/hotplug: Boot HT siblings at least once")
breaks non-SMP builds.

[ I suspect the 'bool' fields should just be made to be bitfields and be
  exposed regardless of configuration, but that's a separate cleanup
  that I'll leave to the owners of this file for later.   - Linus ]

Fixes: 0cc3cd21657b ("cpu/hotplug: Boot HT siblings at least once")
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Abel Vesa <abelvesa@linux.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 kernel/cpu.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -2201,6 +2201,8 @@ void __init boot_cpu_init(void)
  */
 void __init boot_cpu_hotplug_init(void)
 {
+#ifdef CONFIG_SMP
 	this_cpu_write(cpuhp_state.booted_once, true);
+#endif
 	this_cpu_write(cpuhp_state.state, CPUHP_ONLINE);
 }