[PATCH 03/12] powerpc: Replace cpu_up/down with device_online/offline

[Qais Yousef]

The core device API performs extra housekeeping bits that are missing
from directly calling cpu_up/down.

See commit a6717c01ddc2 ("powerpc/rtas: use device model APIs and
serialization during LPM") for an example description of what might go
wrong.

This also prepares to make cpu_up/down a private interface for anything
but the cpu subsystem.

Signed-off-by: Qais Yousef <qais.you...@arm.com>
CC: Benjamin Herrenschmidt <b...@kernel.crashing.org>
CC: Paul Mackerras <pau...@samba.org>
CC: Michael Ellerman <m...@ellerman.id.au>
CC: Enrico Weigelt <i...@metux.net>
CC: Ram Pai <linux...@us.ibm.com>
CC: Nicholas Piggin <npig...@gmail.com>
CC: Thiago Jung Bauermann <bauer...@linux.ibm.com>
CC: Christophe Leroy <christophe.le...@c-s.fr>
CC: Thomas Gleixner <t...@linutronix.de>
CC: linuxppc-dev@lists.ozlabs.org
CC: linux-ker...@vger.kernel.org
---
 arch/powerpc/kernel/machine_kexec_64.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/machine_kexec_64.c 
b/arch/powerpc/kernel/machine_kexec_64.c
index 04a7cba58eff..ebf8cc7acc4d 100644
--- a/arch/powerpc/kernel/machine_kexec_64.c
+++ b/arch/powerpc/kernel/machine_kexec_64.c
@@ -208,13 +208,15 @@ static void wake_offline_cpus(void)
 {
        int cpu = 0;
 
+       lock_device_hotplug();
        for_each_present_cpu(cpu) {
                if (!cpu_online(cpu)) {
                        printk(KERN_INFO "kexec: Waking offline cpu %d.\n",
                               cpu);
-                       WARN_ON(cpu_up(cpu));
+                       WARN_ON(device_online(get_cpu_device(cpu)));
                }
        }
+       unlock_device_hotplug();
 }
 
 static void kexec_prepare_cpus(void)
-- 
2.17.1