You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
99 lines
2.4 KiB
99 lines
2.4 KiB
14 years ago
|
/*
|
||
|
|
* Copyright 2011 Samy Al Bahra.
|
||
|
|
* All rights reserved.
|
||
|
|
*
|
||
|
|
* Redistribution and use in source and binary forms, with or without
|
||
|
|
* modification, are permitted provided that the following conditions
|
||
|
|
* are met:
|
||
|
|
* 1. Redistributions of source code must retain the above copyright
|
||
|
|
* notice, this list of conditions and the following disclaimer.
|
||
|
|
* 2. 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.
|
||
|
|
*
|
||
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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 _CK_RWLOCK_H
|
||
|
|
#define _CK_RWLOCK_H
|
||
|
|
|
||
|
|
#include <ck_pr.h>
|
||
|
|
#include <stdbool.h>
|
||
|
|
#include <stddef.h>
|
||
|
|
|
||
|
|
struct ck_rwlock {
|
||
|
|
unsigned int writer;
|
||
|
|
unsigned int n_readers;
|
||
|
|
};
|
||
|
|
typedef struct ck_rwlock ck_rwlock_t;
|
||
|
|
|
||
|
|
#define CK_RWLOCK_INITIALIZER {false, 0}
|
||
|
|
|
||
|
|
CK_CC_INLINE static void
|
||
|
|
ck_rwlock_init(struct ck_rwlock *rw)
|
||
|
|
{
|
||
|
|
|
||
|
|
rw->writer = 0;
|
||
|
|
rw->n_readers = 0;
|
||
|
|
ck_pr_fence_memory();
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
CK_CC_INLINE static void
|
||
|
|
ck_rwlock_write_lock(ck_rwlock_t *rw)
|
||
|
|
{
|
||
|
|
|
||
|
|
while (ck_pr_fas_uint(&rw->writer, true) == true)
|
||
|
|
ck_pr_stall();
|
||
|
|
|
||
|
|
while (ck_pr_load_uint(&rw->n_readers) != 0)
|
||
|
|
ck_pr_stall();
|
||
|
|
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
CK_CC_INLINE static void
|
||
|
|
ck_rwlock_write_unlock(ck_rwlock_t *rw)
|
||
|
|
{
|
||
|
|
|
||
|
|
ck_pr_store_uint(&rw->writer, false);
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
CK_CC_INLINE static void
|
||
|
|
ck_rwlock_read_lock(ck_rwlock_t *rw)
|
||
|
|
{
|
||
|
|
|
||
|
|
for (;;) {
|
||
|
|
while (ck_pr_load_uint(&rw->writer) == true)
|
||
|
|
ck_pr_stall();
|
||
|
|
|
||
|
|
ck_pr_inc_uint(&rw->n_readers);
|
||
|
|
if (ck_pr_load_uint(&rw->writer) == false)
|
||
|
|
break;
|
||
|
|
ck_pr_dec_uint(&rw->n_readers);
|
||
|
|
}
|
||
|
|
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
CK_CC_INLINE static void
|
||
|
|
ck_rwlock_read_unlock(ck_rwlock_t *rw)
|
||
|
|
{
|
||
|
|
|
||
|
|
ck_pr_dec_uint(&rw->n_readers);
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
#endif /* _CK_RWLOCK_H */
|