// 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" 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 ) ; / * * * cpufreq_this_cpu_can_update - Check if cpufreq policy can be updated . * @ policy : cpufreq policy to check . * * Return ' true ' if : * - the local and remote CPUs share @ policy , * - dvfs_possible_from_any_cpu is set in @ policy and the local CPU is not going * offline ( in which case it is not expected to run cpufreq updates any more ) . * / bool cpufreq_this_cpu_can_update ( struct cpufreq_policy * policy ) { return cpumask_test_cpu ( smp_processor_id ( ) , policy - > cpus ) | | ( policy - > dvfs_possible_from_any_cpu & & rcu_dereference_sched ( * this_cpu_ptr ( & cpufreq_update_util_data ) ) ) ; }
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