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/*
* Sleepable Read-Copy Update mechanism for mutual exclusion
*
* 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
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* 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, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* Copyright (C) IBM Corporation, 2006
*
* Author: Paul McKenney <paulmck@us.ibm.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>
struct srcu_struct_array {
int c[2];
};
struct srcu_struct {
int completed;
struct srcu_struct_array __percpu *per_cpu_ref;
struct mutex mutex;
#ifdef CONFIG_DEBUG_LOCK_ALLOC
struct lockdep_map dep_map;
#endif
};
#ifndef CONFIG_PREEMPT
#define srcu_barrier() barrier()
#else
#define srcu_barrier()
#endif
#ifdef CONFIG_DEBUG_LOCK_ALLOC
int __init_srcu_struct(struct srcu_struct *sp, const char *name,
struct lock_class_key *key);
#define init_srcu_struct(sp) \
({ \
static struct lock_class_key __srcu_key; \
\
__init_srcu_struct((sp), #sp, &__srcu_key); \
})
#else
int init_srcu_struct(struct srcu_struct *sp);
#endif
void cleanup_srcu_struct(struct srcu_struct *sp);
int __srcu_read_lock(struct srcu_struct *sp) __acquires(sp);
void __srcu_read_unlock(struct srcu_struct *sp, int idx) __releases(sp);
void synchronize_srcu(struct srcu_struct *sp);
void synchronize_srcu_expedited(struct srcu_struct *sp);
long srcu_batches_completed(struct srcu_struct *sp);
#ifdef CONFIG_DEBUG_LOCK_ALLOC
static inline int srcu_read_lock_held(struct srcu_struct *sp)
{
if (!debug_lockdep_rcu_enabled())
return 1;
if (rcu_is_cpu_idle())
return 0;
if (!rcu_lockdep_current_cpu_online())
return 0;
return lock_is_held(&sp->dep_map);
}
#else
static inline int srcu_read_lock_held(struct srcu_struct *sp)
{
return 1;
}
#endif
#define srcu_dereference_check(p, sp, c) \
__rcu_dereference_check((p), srcu_read_lock_held(sp) || (c), __rcu)
#define srcu_dereference(p, sp) srcu_dereference_check((p), (sp), 0)
static inline int srcu_read_lock(struct srcu_struct *sp) __acquires(sp)
{
int retval = __srcu_read_lock(sp);
rcu_lock_acquire(&(sp)->dep_map);
rcu_lockdep_assert(!rcu_is_cpu_idle(),
"srcu_read_lock() used illegally while idle");
return retval;
}
static inline void srcu_read_unlock(struct srcu_struct *sp, int idx)
__releases(sp)
{
rcu_lockdep_assert(!rcu_is_cpu_idle(),
"srcu_read_unlock() used illegally while idle");
rcu_lock_release(&(sp)->dep_map);
__srcu_read_unlock(sp, idx);
}
static inline int srcu_read_lock_raw(struct srcu_struct *sp)
{
unsigned long flags;
int ret;
local_irq_save(flags);
ret = __srcu_read_lock(sp);
local_irq_restore(flags);
return ret;
}
static inline void srcu_read_unlock_raw(struct srcu_struct *sp, int idx)
{
unsigned long flags;
local_irq_save(flags);
__srcu_read_unlock(sp, idx);
local_irq_restore(flags);
}
#endif
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