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cpufreq / sched: Pass flags to cpufreq_update_util()
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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
14DEFINE_PER_CPU(struct update_util_data *, cpufreq_update_util_data);
15
16/**
0bed612b 17 * cpufreq_add_update_util_hook - Populate the CPU's update_util_data pointer.
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18 * @cpu: The CPU to set the pointer for.
19 * @data: New pointer value.
0bed612b 20 * @func: Callback function to set for the CPU.
adaf9fcd 21 *
0bed612b 22 * Set and publish the update_util_data pointer for the given CPU.
adaf9fcd 23 *
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24 * The update_util_data pointer of @cpu is set to @data and the callback
25 * function pointer in the target struct update_util_data is set to @func.
26 * That function will be called by cpufreq_update_util() from RCU-sched
27 * read-side critical sections, so it must not sleep. @data will always be
28 * passed to it as the first argument which allows the function to get to the
29 * target update_util_data structure and its container.
30 *
31 * The update_util_data pointer of @cpu must be NULL when this function is
32 * called or it will WARN() and return with no effect.
adaf9fcd 33 */
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34void cpufreq_add_update_util_hook(int cpu, struct update_util_data *data,
35 void (*func)(struct update_util_data *data, u64 time,
58919e83 36 unsigned int flags))
adaf9fcd 37{
0bed612b 38 if (WARN_ON(!data || !func))
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39 return;
40
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41 if (WARN_ON(per_cpu(cpufreq_update_util_data, cpu)))
42 return;
43
44 data->func = func;
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45 rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), data);
46}
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47EXPORT_SYMBOL_GPL(cpufreq_add_update_util_hook);
48
49/**
50 * cpufreq_remove_update_util_hook - Clear the CPU's update_util_data pointer.
51 * @cpu: The CPU to clear the pointer for.
52 *
53 * Clear the update_util_data pointer for the given CPU.
54 *
55 * Callers must use RCU-sched callbacks to free any memory that might be
56 * accessed via the old update_util_data pointer or invoke synchronize_sched()
57 * right after this function to avoid use-after-free.
58 */
59void cpufreq_remove_update_util_hook(int cpu)
60{
61 rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), NULL);
62}
63EXPORT_SYMBOL_GPL(cpufreq_remove_update_util_hook);