From: Thomas Gleixner <tglx@linutronix.de>
Date: Tue, 29 May 2018 15:49:05 +0000 (+0200)
Subject: cpu/hotplug: Split do_cpu_down()
X-Git-Tag: v4.1.12-124.31.3~660
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=3bc66d9ca7e7753b157927a238e021415663d096;p=users%2Fjedix%2Flinux-maple.git

cpu/hotplug: Split do_cpu_down()

Split out the inner workings of do_cpu_down() to allow reuse of that
function for the upcoming SMT disabling mechanism.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>

Orabug: 28220674
CVE: CVE-2018-3620

(cherry picked from commit cc1fe215e1efa406b03aa4389e6269b61342dec5)

Signed-off-by: Mihai Carabas <mihai.carabas@oracle.com>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

Conflicts:
	kernel/cpu.c
Contextual and we do not have cpuhp_state target.
---

diff --git a/kernel/cpu.c b/kernel/cpu.c
index f40ed44bb412..d3142aabd92d 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -444,20 +444,19 @@ out_release:
 	return err;
 }
 
+static int cpu_down_maps_locked(unsigned int cpu)
+{
+	if (cpu_hotplug_disabled)
+		return -EBUSY;
+	return _cpu_down(cpu, 0);
+}
+
 int __ref cpu_down(unsigned int cpu)
 {
 	int err;
 
 	cpu_maps_update_begin();
-
-	if (cpu_hotplug_disabled) {
-		err = -EBUSY;
-		goto out;
-	}
-
-	err = _cpu_down(cpu, 0);
-
-out:
+	err = cpu_down_maps_locked(cpu);
 	cpu_maps_update_done();
 	return err;
 }