mirror of
https://github.com/torvalds/linux.git
synced 2024-11-18 10:01:43 +00:00
b10abd0a88
Recently I added an RCU annotation check to rcu_assign_pointer(). All pointers assigned to RCU protected data are to be annotated with __rcu inorder to be able to use rcu_assign_pointer() similar to checks in other RCU APIs. This resulted in a sparse error: kernel//sched/cpufreq.c:41:9: sparse: error: incompatible types in comparison expression (different address spaces) Fix this by annotating cpufreq_update_util_data pointer with __rcu. This will also help sparse catch any future RCU misuage bugs. Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> [ From an RCU perspective. ] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Paul E. McKenney <paulmck@linux.ibm.com> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: keescook@chromium.org Cc: kernel-hardening@lists.openwall.com Cc: kernel-team@android.com Link: https://lkml.kernel.org/r/20190321003426.160260-2-joel@joelfernandes.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
60 lines
2.1 KiB
C
60 lines
2.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* Scheduler code and data structures related to cpufreq.
|
|
*
|
|
* Copyright (C) 2016, Intel Corporation
|
|
* Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
|
|
*/
|
|
#include "sched.h"
|
|
|
|
DEFINE_PER_CPU(struct update_util_data __rcu *, 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 callbacks to free any memory that might be
|
|
* accessed via the old update_util_data pointer or invoke synchronize_rcu()
|
|
* 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);
|