Adding upstream version 0.6.0.

Signed-off-by: Daniel Baumann <daniel@debian.org>

include/ck_rwlock.h

@@ -0,0 +1,302 @@
+/*
+ * 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 */