1 // SPDX-License-Identifier: CDDL-1.0
2 /*
3 * CDDL HEADER START
4 *
5 * The contents of this file are subject to the terms of the
6 * Common Development and Distribution License (the "License").
7 * You may not use this file except in compliance with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or https://opensource.org/licenses/CDDL-1.0.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22 /*
23 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
24 * Copyright (c) 2012, 2018 by Delphix. All rights reserved.
25 * Copyright (c) 2016 Actifio, Inc. All rights reserved.
26 * Copyright (c) 2025, Klara, Inc.
27 */
28
29 #include <assert.h>
30 #include <pthread.h>
31 #include <errno.h>
32 #include <atomic.h>
33 #include <sys/rwlock.h>
34
35 /*
36 * =========================================================================
37 * rwlocks
38 * =========================================================================
39 */
40
41 void
rw_init(krwlock_t * rwlp,char * name,int type,void * arg)42 rw_init(krwlock_t *rwlp, char *name, int type, void *arg)
43 {
44 (void) name, (void) type, (void) arg;
45 VERIFY0(pthread_rwlock_init(&rwlp->rw_lock, NULL));
46 rwlp->rw_readers = 0;
47 rwlp->rw_owner = 0;
48 }
49
50 void
rw_destroy(krwlock_t * rwlp)51 rw_destroy(krwlock_t *rwlp)
52 {
53 VERIFY0(pthread_rwlock_destroy(&rwlp->rw_lock));
54 }
55
56 void
rw_enter(krwlock_t * rwlp,krw_t rw)57 rw_enter(krwlock_t *rwlp, krw_t rw)
58 {
59 if (rw == RW_READER) {
60 VERIFY0(pthread_rwlock_rdlock(&rwlp->rw_lock));
61 atomic_inc_uint(&rwlp->rw_readers);
62 } else {
63 VERIFY0(pthread_rwlock_wrlock(&rwlp->rw_lock));
64 rwlp->rw_owner = pthread_self();
65 }
66 }
67
68 void
rw_exit(krwlock_t * rwlp)69 rw_exit(krwlock_t *rwlp)
70 {
71 if (RW_READ_HELD(rwlp))
72 atomic_dec_uint(&rwlp->rw_readers);
73 else
74 rwlp->rw_owner = 0;
75
76 VERIFY0(pthread_rwlock_unlock(&rwlp->rw_lock));
77 }
78
79 int
rw_tryenter(krwlock_t * rwlp,krw_t rw)80 rw_tryenter(krwlock_t *rwlp, krw_t rw)
81 {
82 int error;
83
84 if (rw == RW_READER)
85 error = pthread_rwlock_tryrdlock(&rwlp->rw_lock);
86 else
87 error = pthread_rwlock_trywrlock(&rwlp->rw_lock);
88
89 if (error == 0) {
90 if (rw == RW_READER)
91 atomic_inc_uint(&rwlp->rw_readers);
92 else
93 rwlp->rw_owner = pthread_self();
94
95 return (1);
96 }
97
98 VERIFY3S(error, ==, EBUSY);
99
100 return (0);
101 }
102
103 int
rw_tryupgrade(krwlock_t * rwlp)104 rw_tryupgrade(krwlock_t *rwlp)
105 {
106 (void) rwlp;
107 return (0);
108 }
109