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  +   ˆl–Ü4ý( ©³( 	Å€fàB¦-ÿÁ„d_†I|¥+ÁÅ 1º    /* SPDX-License-Identifier: GPL-2.0+ */
/*
 * Sleepable Read-Copy Update mechanism for mutual exclusion
 *
 * Copyright (C) IBM Corporation, 2006
 * Copyright (C) Fujitsu, 2012
 *
 * Author: Paul McKenney <paulmck@linux.ibm.com>
 *	   Lai Jiangshan <laijs@cn.fujitsu.com>
 *
 * For detailed explanation of Read-Copy Update mechanism see -
 *		Documentation/RCU/ *.txt
 *
 */

#ifndef _LINUX_SRCU_H
#define _LINUX_SRCU_H

#include <linux/mutex.h>
#include <linux/rcupdate.h>
#include <linux/workqueue.h>
#include <linux/rcu_segcblist.h>

struct srcu_struct;

#ifdef CONFIG_DEBUG_LOCK_ALLOC

int __init_srcu_struct(struct srcu_struct *ssp, const char *name,
		       struct lock_class_key *key);

#define init_srcu_struct(ssp) \
({ \
	static struct lock_class_key __srcu_key; \
	\
	__init_srcu_struct((ssp), #ssp, &__srcu_key); \
})

#define __SRCU_DEP_MAP_INIT(srcu_name)	.dep_map = { .name = #srcu_name },
#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */

int init_srcu_struct(struct srcu_struct *ssp);

#define __SRCU_DEP_MAP_INIT(srcu_name)
#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */

#ifdef CONFIG_TINY_SRCU
#include <linux/srcutiny.h>
#elif defined(CONFIG_TREE_SRCU)
#include <linux/srcutree.h>
#else
#error "Unknown SRCU implementation specified to kernel configuration"
#endif

void call_srcu(struct srcu_struct *ssp, struct rcu_head *head,
		void (*func)(struct rcu_head *head));
void cleanup_srcu_struct(struct srcu_struct *ssp);
int __srcu_read_lock(struct srcu_struct *ssp) __acquires(ssp);
void __srcu_read_unlock(struct srcu_struct *ssp, int idx) __releases(ssp);
void synchronize_srcu(struct srcu_struct *ssp);

#define SRCU_GET_STATE_COMPLETED 0x1

/**
 * get_completed_synchronize_srcu - Return a pre-completed polled state cookie
 *
 * Returns a value that poll_state_synchronize_srcu() will always treat
 * as a cookie whose grace period has already completed.
 */
static inline unsigned long get_completed_synchronize_srcu(void)
{
	return SRCU_GET_STATE_COMPLETED;
}

unsigned long get_state_synchronize_srcu(struct srcu_struct *ssp);
unsigned long start_poll_synchronize_srcu(struct srcu_struct *ssp);
bool poll_state_synchronize_srcu(struct srcu_struct *ssp, unsigned long cookie);

// Maximum number of unsigned long values corresponding to
// not-yet-completed SRCU grace periods.
#define NUM_ACTIVE_SRCU_POLL_OLDSTATE 2

/**
 * same_state_synchronize_srcu - Are two old-state values identical?
 * @oldstate1: First old-state value.
 * @oldstate2: Second old-state value.
 *
 * The two old-state values must have been obtained from either
 * get_state_synchronize_srcu(), start_poll_synchronize_srcu(), or
 * get_completed_synchronize_srcu().  Returns @true if the two values are
 * identical and @false otherwise.  This allows structures whose lifetimes
 * are tracked by old-state values to push these values to a list header,
 * allowing those structures to be slightly smaller.
 */
static inline bool same_state_synchronize_srcu(unsigned long oldstate1, unsigned long oldstate2)
{
	return oldstate1 == oldstate2;
}

#ifdef CONFIG_NEED_SRCU_NMI_SAFE
int __srcu_read_lock_nmisafe(struct srcu_struct *ssp) __acquires(ssp);
void __srcu_read_unlock_nmisafe(struct srcu_struct *ssp, int idx) __releases(ssp);
#else
static inline int __srcu_read_lock_nmisafe(struct srcu_struct *ssp)
{
	return __srcu_read_lock(ssp);
}
static inline void __srcu_read_unlock_nmisafe(struct srcu_struct *ssp, int idx)
{
	__srcu_read_unlock(ssp, idx);
}
#endif /* CONFIG_NEED_SRCU_NMI_SAFE */

void srcu_init(void);

#ifdef CONFIG_DEBUG_LOCK_ALLOC

/**
 * srcu_read_lock_held - might we be in SRCU read-side critical section?
 * @ssp: The srcu_struct structure to check
 *
 * If CONFIG_DEBUG_LOCK_ALLOC is selected, returns nonzero iff in an SRCU
 * read-side critical section.  In absence of CONFIG_DEBUG_LOCK_ALLOC,
 * this assumes we are in an SRCU read-side critical section unless it can
 * prove otherwise.
 *
 * Checks debug_lockdep_rcu_enabled() to prevent false positives during boot
 * and while lockdep is disabled.
 *
 *