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| author | Josh Triplett <josh@joshtriplett.org> | 2011-12-03 21:06:50 (GMT) |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2011-12-11 18:32:20 (GMT) |
| commit | 2987557f52b97f679f0c324d8f51b8d66e1f2084 (patch) | |
| tree | 93264730d265ef1987e45a97989d75b7a966dbab | |
| parent | 2d1dc9a600edf33321bcdc1c808b7957d8a3f3e1 (diff) | |
| download | linux-2987557f52b97f679f0c324d8f51b8d66e1f2084.tar.xz | |
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>
| -rw-r--r-- | drivers/base/cpu.c | 7 | ||||
| -rw-r--r-- | include/linux/cpu.h | 1 |
2 files changed, 8 insertions, 0 deletions
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c index 251acea..3991502 100644 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -247,6 +247,13 @@ struct sys_device *get_cpu_sysdev(unsigned cpu) } EXPORT_SYMBOL_GPL(get_cpu_sysdev); +bool cpu_is_hotpluggable(unsigned cpu) +{ + struct sys_device *dev = get_cpu_sysdev(cpu); + return dev && container_of(dev, struct cpu, sysdev)->hotpluggable; +} +EXPORT_SYMBOL_GPL(cpu_is_hotpluggable); + int __init cpu_dev_init(void) { int err; diff --git a/include/linux/cpu.h b/include/linux/cpu.h index 6cb60fd..305c263 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -27,6 +27,7 @@ struct cpu { extern int register_cpu(struct cpu *cpu, int num); extern struct sys_device *get_cpu_sysdev(unsigned cpu); +extern bool cpu_is_hotpluggable(unsigned cpu); extern int cpu_add_sysdev_attr(struct sysdev_attribute *attr); extern void cpu_remove_sysdev_attr(struct sysdev_attribute *attr); |