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Subject[PATCH v3 07/15] x86: Replace cpu_up/down with add/remove_cpu
Date
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.yousef@arm.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Ingo Molnar <mingo@redhat.com>
CC: Borislav Petkov <bp@alien8.de>
CC: "H. Peter Anvin" <hpa@zytor.com>
CC: x86@kernel.org
CC: linux-kernel@vger.kernel.org
---
arch/x86/kernel/topology.c | 22 ++++++----------------
arch/x86/mm/mmio-mod.c | 4 ++--
arch/x86/xen/smp.c | 2 +-
3 files changed, 9 insertions(+), 19 deletions(-)

diff --git a/arch/x86/kernel/topology.c b/arch/x86/kernel/topology.c
index be5bc2e47c71..b8810ebbc8ae 100644
--- a/arch/x86/kernel/topology.c
+++ b/arch/x86/kernel/topology.c
@@ -59,39 +59,29 @@ __setup("cpu0_hotplug", enable_cpu0_hotplug);
*/
int _debug_hotplug_cpu(int cpu, int action)
{
- struct device *dev = get_cpu_device(cpu);
int ret;

if (!cpu_is_hotpluggable(cpu))
return -EINVAL;

- lock_device_hotplug();
-
switch (action) {
case 0:
- ret = cpu_down(cpu);
- if (!ret) {
+ ret = remove_cpu(cpu);
+ if (!ret)
pr_info("DEBUG_HOTPLUG_CPU0: CPU %u is now offline\n", cpu);
- dev->offline = true;
- kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
- } else
+ else
pr_debug("Can't offline CPU%d.\n", cpu);
break;
case 1:
- ret = cpu_up(cpu);
- if (!ret) {
- dev->offline = false;
- kobject_uevent(&dev->kobj, KOBJ_ONLINE);
- } else {
+ ret = add_cpu(cpu);
+ if (ret)
pr_debug("Can't online CPU%d.\n", cpu);
- }
+
break;
default:
ret = -EINVAL;
}

- unlock_device_hotplug();
-
return ret;
}

diff --git a/arch/x86/mm/mmio-mod.c b/arch/x86/mm/mmio-mod.c
index 673de6063345..109325d77b3e 100644
--- a/arch/x86/mm/mmio-mod.c
+++ b/arch/x86/mm/mmio-mod.c
@@ -386,7 +386,7 @@ static void enter_uniprocessor(void)
put_online_cpus();

for_each_cpu(cpu, downed_cpus) {
- err = cpu_down(cpu);
+ err = remove_cpu(cpu);
if (!err)
pr_info("CPU%d is down.\n", cpu);
else
@@ -406,7 +406,7 @@ static void leave_uniprocessor(void)
return;
pr_notice("Re-enabling CPUs...\n");
for_each_cpu(cpu, downed_cpus) {
- err = cpu_up(cpu);
+ err = add_cpu(cpu);
if (!err)
pr_info("enabled CPU%d.\n", cpu);
else
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 7a43b2ae19f1..2097fa0ebdb5 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -132,7 +132,7 @@ void __init xen_smp_cpus_done(unsigned int max_cpus)
if (xen_vcpu_nr(cpu) < MAX_VIRT_CPUS)
continue;

- rc = cpu_down(cpu);
+ rc = remove_cpu(cpu);

if (rc == 0) {
/*
--
2.17.1
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