/* * Scheduler code and data structures related to cpufreq. * * Copyright (C) 2016, Intel Corporation * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include "sched.h" DEFINE_PER_CPU(struct update_util_data *, cpufreq_update_util_data); /** * cpufreq_add_update_util_hook - Populate the CPU's update_util_data pointer. * @cpu: The CPU to set the pointer for. * @data: New pointer value. * @func: Callback function to set for the CPU. * * Set and publish the update_util_data pointer for the given CPU. * * The update_util_data pointer of @cpu is set to @data and the callback * function pointer in the target struct update_util_data is set to @func. * That function will be called by cpufreq_update_util() from RCU-sched * read-side critical sections, so it must not sleep.  @data will always be * passed to it as the first argument which allows the function to get to the * target update_util_data structure and its container. * * The update_util_data pointer of @cpu must be NULL when this function is * called or it will WARN() and return with no effect. */void cpufreq_add_update_util_hook(int cpu, struct update_util_data *data,			void (*func)(struct update_util_data *data, u64 time,				     unsigned int flags)){	if (WARN_ON(!data || !func))		return; 	if (WARN_ON(per_cpu(cpufreq_update_util_data, cpu)))		return; 	data->func = func;	rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), data);}EXPORT_SYMBOL_GPL(cpufreq_add_update_util_hook); /** * cpufreq_remove_update_util_hook - Clear the CPU's update_util_data pointer. * @cpu: The CPU to clear the pointer for. * * Clear the update_util_data pointer for the given CPU. * * Callers must use RCU-sched callbacks to free any memory that might be * accessed via the old update_util_data pointer or invoke synchronize_sched() * right after this function to avoid use-after-free. */void cpufreq_remove_update_util_hook(int cpu){	rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), NULL);}EXPORT_SYMBOL_GPL(cpufreq_remove_update_util_hook);