diff options
| author | Qais Yousef <qais.yousef@arm.com> | 2020-03-23 13:50:54 +0000 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-03-25 12:59:31 +0100 |
| commit | 93ef1429e556f739a208e3968883ed51480580e8 (patch) | |
| tree | 66175ce1fa49e5f3b4473accce6db3a4a5adb154 | |
| parent | fd3eafda8f146d4ad8f95f91a8c2b9a5319ff6b2 (diff) | |
cpu/hotplug: Add new {add,remove}_cpu() functions
The new functions use device_{online,offline}() which are userspace safe.
This is in preparation to move cpu_{up, down} kernel users to use a safer
interface that is not racy with userspace.
Suggested-by: "Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: Qais Yousef <qais.yousef@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lkml.kernel.org/r/20200323135110.30522-2-qais.yousef@arm.com
| -rw-r--r-- | include/linux/cpu.h | 2 | ||||
| -rw-r--r-- | kernel/cpu.c | 24 |
2 files changed, 26 insertions, 0 deletions
diff --git a/include/linux/cpu.h b/include/linux/cpu.h index 1ca2baf817ed..cf8cf38dca43 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -89,6 +89,7 @@ extern ssize_t arch_cpu_release(const char *, size_t); #ifdef CONFIG_SMP extern bool cpuhp_tasks_frozen; int cpu_up(unsigned int cpu); +int add_cpu(unsigned int cpu); void notify_cpu_starting(unsigned int cpu); extern void cpu_maps_update_begin(void); extern void cpu_maps_update_done(void); @@ -118,6 +119,7 @@ extern void cpu_hotplug_disable(void); extern void cpu_hotplug_enable(void); void clear_tasks_mm_cpumask(int cpu); int cpu_down(unsigned int cpu); +int remove_cpu(unsigned int cpu); #else /* CONFIG_HOTPLUG_CPU */ diff --git a/kernel/cpu.c b/kernel/cpu.c index 9c706af713fb..069802f7010f 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -1057,6 +1057,18 @@ int cpu_down(unsigned int cpu) } EXPORT_SYMBOL(cpu_down); +int remove_cpu(unsigned int cpu) +{ + int ret; + + lock_device_hotplug(); + ret = device_offline(get_cpu_device(cpu)); + unlock_device_hotplug(); + + return ret; +} +EXPORT_SYMBOL_GPL(remove_cpu); + #else #define takedown_cpu NULL #endif /*CONFIG_HOTPLUG_CPU*/ @@ -1209,6 +1221,18 @@ int cpu_up(unsigned int cpu) } EXPORT_SYMBOL_GPL(cpu_up); +int add_cpu(unsigned int cpu) +{ + int ret; + + lock_device_hotplug(); + ret = device_online(get_cpu_device(cpu)); + unlock_device_hotplug(); + + return ret; +} +EXPORT_SYMBOL_GPL(add_cpu); + #ifdef CONFIG_PM_SLEEP_SMP static cpumask_var_t frozen_cpus; |