rcutiny.h
/* SPDX-License-Identifier: GPL-2.0+ */
/*
* Read-Copy Update mechanism for mutual exclusion, the Bloatwatch edition.
*
* Copyright IBM Corporation, 2008
*
* Author: Paul E. McKenney <paulmck@linux.ibm.com>
*
* For detailed explanation of Read-Copy Update mechanism see -
* Documentation/RCU
*/
#ifndef __LINUX_TINY_H
#define __LINUX_TINY_H
#include <asm/param.h> /* for HZ */
struct rcu_gp_oldstate {
unsigned long rgos_norm;
};
// Maximum number of rcu_gp_oldstate values corresponding to
// not-yet-completed RCU grace periods.
#define NUM_ACTIVE_RCU_POLL_FULL_OLDSTATE 2
/*
* Are the two oldstate values the same? See the Tree RCU version for
* docbook header.
*/
static inline bool same_state_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp1,
struct rcu_gp_oldstate *rgosp2)
{
return rgosp1->rgos_norm == rgosp2->rgos_norm;
}
unsigned long get_state_synchronize_rcu(void);
static inline void get_state_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp)
{
rgosp->rgos_norm = get_state_synchronize_rcu();
}
unsigned long start_poll_synchronize_rcu(void);
static inline void start_poll_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp)
{
rgosp->rgos_norm = start_poll_synchronize_rcu();
}
bool poll_state_synchronize_rcu(unsigned long oldstate);
static inline bool poll_state_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp)
{
return poll_state_synchronize_rcu(rgosp->rgos_norm);
}
static inline void cond_synchronize_rcu(unsigned long oldstate)
{
might_sleep();
}
static inline void cond_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp)
{
cond_synchronize_rcu(rgosp->rgos_norm);
}
static inline unsigned long start_poll_synchronize_rcu_expedited(void)
{
return start_poll_synchronize_rcu();
}
static inline void start_poll_synchronize_rcu_expedited_full(struct rcu_gp_oldstate *rgosp)
{
rgosp->rgos_norm = start_poll_synchronize_rcu_expedited();
}
static inline void cond_synchronize_rcu_expedited(unsigned long oldstate)
{
cond_synchronize_rcu(oldstate);
}
static inline void cond_synchronize_rcu_expedited_full(struct rcu_gp_oldstate *rgosp)
{
cond_synchronize_rcu_expedited(rgosp->rgos_norm);
}
extern void rcu_barrier(void);
static inline void synchronize_rcu_expedited(void)
{
synchronize_rcu();
}
/*
* Add one more declaration of kvfree() here. It is
* not so straight forward to just include <linux/mm.h>
* where it is defined due to getting many compile
* errors caused by that include.
*/
extern void kvfree(const void *addr);
static inline void __kvfree_call_rcu(struct rcu_head *head, void *ptr)
{
if (head) {
call_rcu(head, (rcu_callback_t) ((void *) head - ptr));
return;
}
// kvfree_rcu(one_arg) call.
might_sleep();
synchronize_rcu();
kvfree(ptr);
}
#ifdef CONFIG_KASAN_GENERIC
void kvfree_call_rcu(struct rcu_head *head, void *ptr);
#else
static inline void kvfree_call_rcu(struct rcu_head *head, void *ptr)
{
__kvfree_call_rcu(head, ptr);
}
#endif
void rcu_qs(void);
static inline void rcu_softirq_qs(void)
{
rcu_qs();
}
#define rcu_note_context_switch(preempt) \
do { \
rcu_qs(); \
rcu_tasks_qs(current, (preempt)); \
} while (0)
static inline int rcu_needs_cpu(void)
{
return 0;
}
static inline void rcu_request_urgent_qs_task(struct task_struct *t) { }
/*
* Take advantage of the fact that there is only one CPU, which
* allows us to ignore virtualization-based context switches.
*/
static inline void rcu_virt_note_context_switch(void) { }
static inline void rcu_cpu_stall_reset(void) { }
static inline int rcu_jiffies_till_stall_check(void) { return 21 * HZ; }
static inline void rcu_irq_exit_check_preempt(void) { }
static inline void exit_rcu(void) { }
static inline bool rcu_preempt_need_deferred_qs(struct task_struct *t)
{
return false;
}
static inline void rcu_preempt_deferred_qs(struct task_struct *t) { }
void rcu_scheduler_starting(void);
static inline void rcu_end_inkernel_boot(void) { }
static inline bool rcu_inkernel_boot_has_ended(void) { return true; }
static inline bool rcu_is_watching(void) { return true; }
static inline void rcu_momentary_dyntick_idle(void) { }
static inline void kfree_rcu_scheduler_running(void) { }
static inline bool rcu_gp_might_be_stalled(void) { return false; }
/* Avoid RCU read-side critical sections leaking across. */
static inline void rcu_all_qs(void) { barrier(); }
/* RCUtree hotplug events */
#define rcutree_prepare_cpu NULL
#define rcutree_online_cpu NULL
#define rcutree_offline_cpu NULL
#define rcutree_dead_cpu NULL
#define rcutree_dying_cpu NULL
static inline void rcutree_report_cpu_starting(unsigned int cpu) { }
#endif /* __LINUX_RCUTINY_H */