1 files changed, 108 insertions, 0 deletions
diff --git a/sys/contrib/openzfs/lib/libspl/rwlock.c b/sys/contrib/openzfs/lib/libspl/rwlock.c
new file mode 100644
index 000000000000..3712829ef594
--- /dev/null
+++ b/sys/contrib/openzfs/lib/libspl/rwlock.c
@@ -0,0 +1,108 @@
+// SPDX-License-Identifier: CDDL-1.0
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or https://opensource.org/licenses/CDDL-1.0.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012, 2018 by Delphix. All rights reserved.
+ * Copyright (c) 2016 Actifio, Inc. All rights reserved.
+ * Copyright (c) 2025, Klara, Inc.
+ */
+
+#include <assert.h>
+#include <pthread.h>
+#include <errno.h>
+#include <atomic.h>
+#include <sys/rwlock.h>
+
+/*
+ * =========================================================================
+ * rwlocks
+ * =========================================================================
+ */
+
+void
+rw_init(krwlock_t *rwlp, char *name, int type, void *arg)
+{
+	(void) name, (void) type, (void) arg;
+	VERIFY0(pthread_rwlock_init(&rwlp->rw_lock, NULL));
+	rwlp->rw_readers = 0;
+	rwlp->rw_owner = 0;
+}
+
+void
+rw_destroy(krwlock_t *rwlp)
+{
+	VERIFY0(pthread_rwlock_destroy(&rwlp->rw_lock));
+}
+
+void
+rw_enter(krwlock_t *rwlp, krw_t rw)
+{
+	if (rw == RW_READER) {
+		VERIFY0(pthread_rwlock_rdlock(&rwlp->rw_lock));
+		atomic_inc_uint(&rwlp->rw_readers);
+	} else {
+		VERIFY0(pthread_rwlock_wrlock(&rwlp->rw_lock));
+		rwlp->rw_owner = pthread_self();
+	}
+}
+
+void
+rw_exit(krwlock_t *rwlp)
+{
+	if (RW_READ_HELD(rwlp))
+		atomic_dec_uint(&rwlp->rw_readers);
+	else
+		rwlp->rw_owner = 0;
+
+	VERIFY0(pthread_rwlock_unlock(&rwlp->rw_lock));
+}
+
+int
+rw_tryenter(krwlock_t *rwlp, krw_t rw)
+{
+	int error;
+
+	if (rw == RW_READER)
+		error = pthread_rwlock_tryrdlock(&rwlp->rw_lock);
+	else
+		error = pthread_rwlock_trywrlock(&rwlp->rw_lock);
+
+	if (error == 0) {
+		if (rw == RW_READER)
+			atomic_inc_uint(&rwlp->rw_readers);
+		else
+			rwlp->rw_owner = pthread_self();
+
+		return (1);
+	}
+
+	VERIFY3S(error, ==, EBUSY);
+
+	return (0);
+}
+
+int
+rw_tryupgrade(krwlock_t *rwlp)
+{
+	(void) rwlp;
+	return (0);
+}