1 /* 2 * Scheduler code and data structures related to cpufreq. 3 * 4 * Copyright (C) 2016, Intel Corporation 5 * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 */ 11 12 #include "sched.h" 13 14 DEFINE_PER_CPU(struct update_util_data *, cpufreq_update_util_data); 15 16 /** 17 * cpufreq_set_update_util_data - Populate the CPU's update_util_data pointer. 18 * @cpu: The CPU to set the pointer for. 19 * @data: New pointer value. 20 * 21 * Set and publish the update_util_data pointer for the given CPU. That pointer 22 * points to a struct update_util_data object containing a callback function 23 * to call from cpufreq_update_util(). That function will be called from an RCU 24 * read-side critical section, so it must not sleep. 25 * 26 * Callers must use RCU-sched callbacks to free any memory that might be 27 * accessed via the old update_util_data pointer or invoke synchronize_sched() 28 * right after this function to avoid use-after-free. 29 */ 30 void cpufreq_set_update_util_data(int cpu, struct update_util_data *data) 31 { 32 if (WARN_ON(data && !data->func)) 33 return; 34 35 rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), data); 36 } 37 EXPORT_SYMBOL_GPL(cpufreq_set_update_util_data); 38