[PATCH] i386: introduce the mechanism of disabling cpu hotplug control

Add 'enable_cpu_hotplug' flag and when cleared, the hotplug control file
("online") will not be added under /sys/devices/system/cpu/cpuX/

Next patch doing PCI quirks will use this.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
Cc: "Li, Shaohua" <shaohua.li@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
diff --git a/arch/i386/kernel/topology.c b/arch/i386/kernel/topology.c
index 07d6da3..844c08f 100644
--- a/arch/i386/kernel/topology.c
+++ b/arch/i386/kernel/topology.c
@@ -40,14 +40,18 @@
 	 * restrictions and assumptions in kernel. This basically
 	 * doesnt add a control file, one cannot attempt to offline
 	 * BSP.
+	 *
+	 * Also certain PCI quirks require not to enable hotplug control
+	 * for all CPU's.
 	 */
-	if (!num)
+	if (!num || !enable_cpu_hotplug)
 		cpu_devices[num].cpu.no_control = 1;
 
 	return register_cpu(&cpu_devices[num].cpu, num);
 }
 
 #ifdef CONFIG_HOTPLUG_CPU
+int enable_cpu_hotplug = 1;
 
 void arch_unregister_cpu(int num) {
 	return unregister_cpu(&cpu_devices[num].cpu);