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/*-
* BSD LICENSE
*
* Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Intel Corporation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef _RTE_SPINLOCK_H_
#define _RTE_SPINLOCK_H_
/**
* @file
*
* RTE Spinlocks
*
* This file defines an API for read-write locks, which are implemented
* in an architecture-specific way. This kind of lock simply waits in
* a loop repeatedly checking until the lock becomes available.
*
* All locks must be initialised before use, and only initialised once.
*
*/
#include <rte_lcore.h>
#ifdef RTE_FORCE_INTRINSICS
#include <rte_common.h>
#endif
/**
* The rte_spinlock_t type.
*/
typedef struct {
volatile int locked; /**< lock status 0 = unlocked, 1 = locked */
} rte_spinlock_t;
/**
* A static spinlock initializer.
*/
#define RTE_SPINLOCK_INITIALIZER { 0 }
/**
* Initialize the spinlock to an unlocked state.
*
* @param sl
* A pointer to the spinlock.
*/
static inline void
rte_spinlock_init(rte_spinlock_t *sl)
{
sl->locked = 0;
}
/**
* Take the spinlock.
*
* @param sl
* A pointer to the spinlock.
*/
static inline void
rte_spinlock_lock(rte_spinlock_t *sl);
#ifdef RTE_FORCE_INTRINSICS
static inline void
rte_spinlock_lock(rte_spinlock_t *sl)
{
while (__sync_lock_test_and_set(&sl->locked, 1))
while(sl->locked)
rte_pause();
}
#endif
/**
* Release the spinlock.
*
* @param sl
* A pointer to the spinlock.
*/
static inline void
rte_spinlock_unlock (rte_spinlock_t *sl);
#ifdef RTE_FORCE_INTRINSICS
static inline void
rte_spinlock_unlock (rte_spinlock_t *sl)
{
__sync_lock_release(&sl->locked);
}
#endif
/**
* Try to take the lock.
*
* @param sl
* A pointer to the spinlock.
* @return
* 1 if the lock is successfully taken; 0 otherwise.
*/
static inline int
rte_spinlock_trylock (rte_spinlock_t *sl);
#ifdef RTE_FORCE_INTRINSICS
static inline int
rte_spinlock_trylock (rte_spinlock_t *sl)
{
return (__sync_lock_test_and_set(&sl->locked,1) == 0);
}
#endif
/**
* Test if the lock is taken.
*
* @param sl
* A pointer to the spinlock.
* @return
* 1 if the lock is currently taken; 0 otherwise.
*/
static inline int rte_spinlock_is_locked (rte_spinlock_t *sl)
{
return sl->locked;
}
/**
* The rte_spinlock_recursive_t type.
*/
typedef struct {
rte_spinlock_t sl; /**< the actual spinlock */
volatile int user; /**< core id using lock, -1 for unused */
volatile int count; /**< count of time this lock has been called */
} rte_spinlock_recursive_t;
/**
* A static recursive spinlock initializer.
*/
#define RTE_SPINLOCK_RECURSIVE_INITIALIZER {RTE_SPINLOCK_INITIALIZER, -1, 0}
/**
* Initialize the recursive spinlock to an unlocked state.
*
* @param slr
* A pointer to the recursive spinlock.
*/
static inline void rte_spinlock_recursive_init(rte_spinlock_recursive_t *slr)
{
rte_spinlock_init(&slr->sl);
slr->user = -1;
slr->count = 0;
}
/**
* Take the recursive spinlock.
*
* @param slr
* A pointer to the recursive spinlock.
*/
static inline void rte_spinlock_recursive_lock(rte_spinlock_recursive_t *slr)
{
int id = rte_lcore_id();
if (slr->user != id) {
rte_spinlock_lock(&slr->sl);
slr->user = id;
}
slr->count++;
}
/**
* Release the recursive spinlock.
*
* @param slr
* A pointer to the recursive spinlock.
*/
static inline void rte_spinlock_recursive_unlock(rte_spinlock_recursive_t *slr)
{
if (--(slr->count) == 0) {
slr->user = -1;
rte_spinlock_unlock(&slr->sl);
}
}
/**
* Try to take the recursive lock.
*
* @param slr
* A pointer to the recursive spinlock.
* @return
* 1 if the lock is successfully taken; 0 otherwise.
*/
static inline int rte_spinlock_recursive_trylock(rte_spinlock_recursive_t *slr)
{
int id = rte_lcore_id();
if (slr->user != id) {
if (rte_spinlock_trylock(&slr->sl) == 0)
return 0;
slr->user = id;
}
slr->count++;
return 1;
}
#endif /* _RTE_SPINLOCK_H_ */
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