tree 93264730d265ef1987e45a97989d75b7a966dbab
parent 2d1dc9a600edf33321bcdc1c808b7957d8a3f3e1
author Josh Triplett <josh@joshtriplett.org> 1322946410 -0800
committer Paul E. McKenney <paulmck@linux.vnet.ibm.com> 1323628340 -0800

driver-core/cpu: Expose hotpluggability to the rest of the kernel

When architectures register CPUs, they indicate whether the CPU allows
hotplugging; notably, x86 and ARM don't allow hotplugging CPU 0.
Userspace can easily query the hotpluggability of a CPU via sysfs;
however, the kernel has no convenient way of accessing that property in
an architecture-independent way.  While the kernel can simply try it and
see, some code needs to distinguish between "hotplug failed" and
"hotplug has no hope of working on this CPU"; for example, rcutorture's
CPU hotplug tests want to avoid drowning out real hotplug failures with
expected failures.

Expose this property via a new cpu_is_hotpluggable function, so that the
rest of the kernel can access it in an architecture-independent way.

Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>