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usr / src / sys / contrib / ck / include /

📁 ..
📄 ck_array.h(3.06 KB)
📄 ck_backoff.h(1.84 KB)
📄 ck_barrier.h(5.31 KB)
📄 ck_bitmap.h(12.25 KB)
📄 ck_brlock.h(6.47 KB)
📄 ck_bytelock.h(5.3 KB)
📄 ck_cc.h(3.68 KB)
📄 ck_cohort.h(5.64 KB)
📄 ck_elide.h(8.74 KB)
📄 ck_epoch.h(7.82 KB)
📄 ck_fifo.h(12.87 KB)
📄 ck_hp.h(3.31 KB)
📄 ck_hp_fifo.h(5.99 KB)
📄 ck_hp_stack.h(3.08 KB)
📄 ck_hs.h(4.46 KB)
📄 ck_ht.h(6.51 KB)
📄 ck_limits.h(1.77 KB)
📄 ck_malloc.h(1.57 KB)
📄 ck_md.h(3.91 KB)
📄 ck_pflock.h(3.68 KB)
📄 ck_pr.h(31.64 KB)
📄 ck_queue.h(15.78 KB)
📄 ck_rhs.h(4.41 KB)
📄 ck_ring.h(16.8 KB)
📄 ck_rwcohort.h(11.17 KB)
📄 ck_rwlock.h(6.15 KB)
📄 ck_sequence.h(3.35 KB)
📄 ck_spinlock.h(2.46 KB)
📄 ck_stack.h(9.03 KB)
📄 ck_stdbool.h(1.42 KB)
📄 ck_stddef.h(1.42 KB)
📄 ck_stdint.h(1.55 KB)
📄 ck_stdlib.h(1.42 KB)
📄 ck_string.h(1.42 KB)
📄 ck_swlock.h(5.09 KB)
📄 ck_tflock.h(3.9 KB)
📁 gcc
📁 spinlock

Editing: ck_rwlock.h

/*
 * Copyright 2011-2015 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_elide.h>
#include <ck_pr.h>
#include <ck_stdbool.h>
#include <ck_stddef.h>

struct ck_rwlock {
	unsigned int writer;
	unsigned int n_readers;
};
typedef struct ck_rwlock ck_rwlock_t;

#define CK_RWLOCK_INITIALIZER {0, 0}

CK_CC_INLINE static void
ck_rwlock_init(struct ck_rwlock *rw)
{

rw->writer = 0;
	rw->n_readers = 0;
	ck_pr_barrier();
	return;
}

CK_CC_INLINE static void
ck_rwlock_write_unlock(ck_rwlock_t *rw)
{

ck_pr_fence_unlock();
	ck_pr_store_uint(&rw->writer, 0);
	return;
}

CK_CC_INLINE static bool
ck_rwlock_locked_writer(ck_rwlock_t *rw)
{
	bool r;

r = ck_pr_load_uint(&rw->writer);
	ck_pr_fence_acquire();
	return r;
}

CK_CC_INLINE static void
ck_rwlock_write_downgrade(ck_rwlock_t *rw)
{

ck_pr_inc_uint(&rw->n_readers);
	ck_rwlock_write_unlock(rw);
	return;
}

CK_CC_INLINE static bool
ck_rwlock_locked(ck_rwlock_t *rw)
{
	bool l;

l = ck_pr_load_uint(&rw->n_readers) |
	    ck_pr_load_uint(&rw->writer);
	ck_pr_fence_acquire();
	return l;
}

CK_CC_INLINE static bool
ck_rwlock_write_trylock(ck_rwlock_t *rw)
{

if (ck_pr_fas_uint(&rw->writer, 1) != 0)
		return false;

ck_pr_fence_atomic_load();

if (ck_pr_load_uint(&rw->n_readers) != 0) {
		ck_rwlock_write_unlock(rw);
		return false;
	}

ck_pr_fence_lock();
	return true;
}

CK_ELIDE_TRYLOCK_PROTOTYPE(ck_rwlock_write, ck_rwlock_t,
    ck_rwlock_locked, ck_rwlock_write_trylock)

CK_CC_INLINE static void
ck_rwlock_write_lock(ck_rwlock_t *rw)
{

while (ck_pr_fas_uint(&rw->writer, 1) != 0)
		ck_pr_stall();

ck_pr_fence_atomic_load();

while (ck_pr_load_uint(&rw->n_readers) != 0)
		ck_pr_stall();

ck_pr_fence_lock();
	return;
}

CK_ELIDE_PROTOTYPE(ck_rwlock_write, ck_rwlock_t,
    ck_rwlock_locked, ck_rwlock_write_lock,
    ck_rwlock_locked_writer, ck_rwlock_write_unlock)

CK_CC_INLINE static bool
ck_rwlock_read_trylock(ck_rwlock_t *rw)
{

if (ck_pr_load_uint(&rw->writer) != 0)
		return false;

ck_pr_inc_uint(&rw->n_readers);

/*
	 * Serialize with respect to concurrent write
	 * lock operation.
	 */
	ck_pr_fence_atomic_load();

if (ck_pr_load_uint(&rw->writer) == 0) {
		ck_pr_fence_lock();
		return true;
	}

ck_pr_dec_uint(&rw->n_readers);
	return false;
}

CK_ELIDE_TRYLOCK_PROTOTYPE(ck_rwlock_read, ck_rwlock_t,
    ck_rwlock_locked_writer, ck_rwlock_read_trylock)

CK_CC_INLINE static void
ck_rwlock_read_lock(ck_rwlock_t *rw)
{

for (;;) {
		while (ck_pr_load_uint(&rw->writer) != 0)
			ck_pr_stall();

ck_pr_inc_uint(&rw->n_readers);

/*
		 * Serialize with respect to concurrent write
		 * lock operation.
		 */
		ck_pr_fence_atomic_load();

if (ck_pr_load_uint(&rw->writer) == 0)
			break;

ck_pr_dec_uint(&rw->n_readers);
	}

/* Acquire semantics are necessary. */
	ck_pr_fence_load();
	return;
}

CK_CC_INLINE static bool
ck_rwlock_locked_reader(ck_rwlock_t *rw)
{

ck_pr_fence_load();
	return ck_pr_load_uint(&rw->n_readers);
}

CK_CC_INLINE static void
ck_rwlock_read_unlock(ck_rwlock_t *rw)
{

ck_pr_fence_load_atomic();
	ck_pr_dec_uint(&rw->n_readers);
	return;
}

CK_ELIDE_PROTOTYPE(ck_rwlock_read, ck_rwlock_t,
    ck_rwlock_locked_writer, ck_rwlock_read_lock,
    ck_rwlock_locked_reader, ck_rwlock_read_unlock)

/*
 * Recursive writer reader-writer lock implementation.
 */
struct ck_rwlock_recursive {
	struct ck_rwlock rw;
	unsigned int wc;
};
typedef struct ck_rwlock_recursive ck_rwlock_recursive_t;

#define CK_RWLOCK_RECURSIVE_INITIALIZER {CK_RWLOCK_INITIALIZER, 0}

CK_CC_INLINE static void
ck_rwlock_recursive_write_lock(ck_rwlock_recursive_t *rw, unsigned int tid)
{
	unsigned int o;

o = ck_pr_load_uint(&rw->rw.writer);
	if (o == tid)
		goto leave;

while (ck_pr_cas_uint(&rw->rw.writer, 0, tid) == false)
		ck_pr_stall();

ck_pr_fence_atomic_load();

while (ck_pr_load_uint(&rw->rw.n_readers) != 0)
		ck_pr_stall();

ck_pr_fence_lock();
leave:
	rw->wc++;
	return;
}

CK_CC_INLINE static bool
ck_rwlock_recursive_write_trylock(ck_rwlock_recursive_t *rw, unsigned int tid)
{
	unsigned int o;

o = ck_pr_load_uint(&rw->rw.writer);
	if (o == tid)
		goto leave;

if (ck_pr_cas_uint(&rw->rw.writer, 0, tid) == false)
		return false;

ck_pr_fence_atomic_load();

if (ck_pr_load_uint(&rw->rw.n_readers) != 0) {
		ck_pr_store_uint(&rw->rw.writer, 0);
		return false;
	}

ck_pr_fence_lock();
leave:
	rw->wc++;
	return true;
}

CK_CC_INLINE static void
ck_rwlock_recursive_write_unlock(ck_rwlock_recursive_t *rw)
{

if (--rw->wc == 0) {
		ck_pr_fence_unlock();
		ck_pr_store_uint(&rw->rw.writer, 0);
	}

return;
}

CK_CC_INLINE static void
ck_rwlock_recursive_read_lock(ck_rwlock_recursive_t *rw)
{

ck_rwlock_read_lock(&rw->rw);
	return;
}

CK_CC_INLINE static bool
ck_rwlock_recursive_read_trylock(ck_rwlock_recursive_t *rw)
{

return ck_rwlock_read_trylock(&rw->rw);
}

CK_CC_INLINE static void
ck_rwlock_recursive_read_unlock(ck_rwlock_recursive_t *rw)
{

ck_rwlock_read_unlock(&rw->rw);
	return;
}

#endif /* CK_RWLOCK_H */

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Editing: ck_rwlock.h

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