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Release 4.12 include/linux/rcu_sync.h

Directory: include/linux
 * RCU-based infrastructure for lightweight reader-writer locking
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * GNU General Public License for more details.
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, you can access it online at
 * Copyright (c) 2015, Red Hat, Inc.
 * Author: Oleg Nesterov <>

#ifndef _LINUX_RCU_SYNC_H_

#define _LINUX_RCU_SYNC_H_

#include <linux/wait.h>
#include <linux/rcupdate.h>

enum rcu_sync_type { RCU_SYNC, RCU_SCHED_SYNC, RCU_BH_SYNC };

/* Structure to mediate between updaters and fastpath-using readers.  */

struct rcu_sync {
int			gp_state;
int			gp_count;
wait_queue_head_t	gp_wait;

int			cb_state;
struct rcu_head		cb_head;

enum rcu_sync_type	gp_type;

extern void rcu_sync_lockdep_assert(struct rcu_sync *);

 * rcu_sync_is_idle() - Are readers permitted to use their fastpaths?
 * @rsp: Pointer to rcu_sync structure to use for synchronization
 * Returns true if readers are permitted to use their fastpaths.
 * Must be invoked within an RCU read-side critical section whose
 * flavor matches that of the rcu_sync struture.

static inline bool rcu_sync_is_idle(struct rcu_sync *rsp) { #ifdef CONFIG_PROVE_RCU rcu_sync_lockdep_assert(rsp); #endif return !rsp->gp_state; /* GP_IDLE */ }


Oleg Nesterov29100.00%3100.00%

extern void rcu_sync_init(struct rcu_sync *, enum rcu_sync_type); extern void rcu_sync_enter_start(struct rcu_sync *); extern void rcu_sync_enter(struct rcu_sync *); extern void rcu_sync_exit(struct rcu_sync *); extern void rcu_sync_dtor(struct rcu_sync *); #define __RCU_SYNC_INITIALIZER(name, type) { \ .gp_state = 0, \ .gp_count = 0, \ .gp_wait = __WAIT_QUEUE_HEAD_INITIALIZER(name.gp_wait), \ .cb_state = 0, \ .gp_type = type, \ } #define __DEFINE_RCU_SYNC(name, type) \ struct rcu_sync_struct name = __RCU_SYNC_INITIALIZER(name, type) #define DEFINE_RCU_SYNC(name) \ __DEFINE_RCU_SYNC(name, RCU_SYNC) #define DEFINE_RCU_SCHED_SYNC(name) \ __DEFINE_RCU_SYNC(name, RCU_SCHED_SYNC) #define DEFINE_RCU_BH_SYNC(name) \ __DEFINE_RCU_SYNC(name, RCU_BH_SYNC) #endif /* _LINUX_RCU_SYNC_H_ */

Overall Contributors

Oleg Nesterov17395.05%583.33%
Peter Zijlstra94.95%116.67%
Directory: include/linux
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