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📄 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_sequence.h

/*
 * Copyright 2010-2015 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_SEQUENCE_H
#define CK_SEQUENCE_H

#include <ck_cc.h>
#include <ck_pr.h>
#include <ck_stdbool.h>

struct ck_sequence {
	unsigned int sequence;
};
typedef struct ck_sequence ck_sequence_t;

#define CK_SEQUENCE_INITIALIZER { .sequence = 0 }

CK_CC_INLINE static void
ck_sequence_init(struct ck_sequence *sq)
{

ck_pr_store_uint(&sq->sequence, 0);
	return;
}

CK_CC_INLINE static unsigned int
ck_sequence_read_begin(const struct ck_sequence *sq)
{
	unsigned int version;

for (;;) {
		version = ck_pr_load_uint(&sq->sequence);

/*
		 * If a sequence is even then associated data may be in a
		 * consistent state.
		 */
		if (CK_CC_LIKELY((version & 1) == 0))
			break;

/*
		 * If a sequence is odd then a thread is in the middle of an
		 * update. Retry the read to avoid operating on inconsistent
		 * data.
		 */
		ck_pr_stall();
	}

ck_pr_fence_load();
	return version;
}

CK_CC_INLINE static bool
ck_sequence_read_retry(const struct ck_sequence *sq, unsigned int version)
{

/*
	 * If the sequence number was updated then a read should be
	 * re-attempted.
	 */
	ck_pr_fence_load();
	return ck_pr_load_uint(&sq->sequence) != version;
}

#define CK_SEQUENCE_READ(seqlock, version) 						\
	for (*(version) = 1;								\
	    (*(version) != 0) && (*(version) = ck_sequence_read_begin(seqlock), 1);	\
	    *(version) = ck_sequence_read_retry(seqlock, *(version)))

/*
 * This must be called after a successful mutex acquisition.
 */
CK_CC_INLINE static void
ck_sequence_write_begin(struct ck_sequence *sq)
{

/*
	 * Increment the sequence to an odd number to indicate
	 * the beginning of a write update.
	 */
	ck_pr_store_uint(&sq->sequence, sq->sequence + 1);
	ck_pr_fence_store();
	return;
}

/*
 * This must be called before mutex ownership is relinquished.
 */
CK_CC_INLINE static void
ck_sequence_write_end(struct ck_sequence *sq)
{

/*
	 * Increment the sequence to an even number to indicate
	 * completion of a write update.
	 */
	ck_pr_fence_store();
	ck_pr_store_uint(&sq->sequence, sq->sequence + 1);
	return;
}

#endif /* CK_SEQUENCE_H */

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Editing: ck_sequence.h

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