Commit-ID: 2987557f52b97f679f0c324d8f51b8d66e1f2084
Gitweb: http://git.kernel.org/tip/2987557f52b97f679f0c324d8f51b8d66e1f2084
Author: Josh Triplett <josh@xxxxxxxxxxxxxxxx>
AuthorDate: Sat, 3 Dec 2011 13:06:50 -0800
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
CommitDate: Sun, 11 Dec 2011 10:32:20 -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@xxxxxxxxxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
drivers/base/cpu.c | 7 +++++++
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);
--
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