[PATCH] hotplug: Allow modules to use the cpu hotplug notifiers even if !CONFIG_HOTPLUG_CPU
[PATCH] hotplug: Allow modules to use the cpu hotplug notifiers even if !CONFIG_HOTPLUG_CPU

The following patchset allows a host with running virtual machines to be
suspended and, on at least a subset of the machines tested, resumed.  Note
that this is orthogonal to suspending and resuming an individual guest to a
file.

A side effect of implementing suspend/resume is that cpu hotplug is now
supported.  This should please the owners of big iron.

This patch:

KVM wants the cpu hotplug notifications, both for cpu hotplug itself, but more
commonly for host suspend/resume.

In order to avoid extensive #ifdefs, provide stubs when CONFIG_CPU_HOTPLUG is
not defined.

In all, we have four cases:

- UP: register and unregister stubbed out
- SMP+hotplug: full register and unregister
- SMP, no hotplug, core: register as __init, unregister stubbed
      (cpus are brought up during core initialization)
- SMP, no hotplug, module: register and unregister stubbed out
      (cpus cannot be brought up during module lifetime)

Signed-off-by: Avi Kivity <8f920f22884d6fea9df883843c4a8095a2e5ac6f@qumranet.com>
Cc: Ingo Molnar <9dbbbf0688fedc85ad4da37637f1a64b8c718ee2@elte.hu>
Cc: Rusty Russell <df9728c9e5104131c08c7adb03af425394842596@rustcorp.com.au>
Cc: Oleg Nesterov <20b70f0af00562e63758b9ee42012ecc96c58590@tv-sign.ru>
Signed-off-by: Andrew Morton <5c1e68b099950c134891f0b6e179498a8ebe9cf9@linux-foundation.org>
Signed-off-by: Linus Torvalds <69652caca27c8b940640ad396ab71f93cacec34f@linux-foundation.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas