1/*- 2 * Copyright (c) 2010 Isilon Systems, Inc. 3 * Copyright (c) 2010 iX Systems, Inc. 4 * Copyright (c) 2010 Panasas, Inc. 5 * Copyright (c) 2013-2015 Mellanox Technologies, Ltd. 6 * Copyright (c) 2013 Fran��ois Tigeot 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice unmodified, this list of conditions, and the following 14 * disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 * 30 * $FreeBSD: stable/11/sys/compat/linuxkpi/common/include/linux/kref.h 329961 2018-02-25 10:25:47Z hselasky $ 31 */ 32#ifndef _LINUX_KREF_H_ 33#define _LINUX_KREF_H_ 34 35#include <sys/types.h> 36#include <sys/refcount.h> 37 38#include <linux/compiler.h> 39#include <linux/kernel.h> 40#include <linux/mutex.h> 41 42#include <asm/atomic.h> 43 44struct kref { 45 atomic_t refcount; 46}; 47 48static inline void 49kref_init(struct kref *kref) 50{ 51 52 refcount_init(&kref->refcount.counter, 1); 53} 54 55static inline unsigned int 56kref_read(const struct kref *kref) 57{ 58 59 return (atomic_read(&kref->refcount)); 60} 61 62static inline void 63kref_get(struct kref *kref) 64{ 65 66 refcount_acquire(&kref->refcount.counter); 67} 68 69static inline int 70kref_put(struct kref *kref, void (*rel)(struct kref *kref)) 71{ 72 73 if (refcount_release(&kref->refcount.counter)) { 74 rel(kref); 75 return 1; 76 } 77 return 0; 78} 79 80static inline int 81kref_sub(struct kref *kref, unsigned int count, 82 void (*rel)(struct kref *kref)) 83{ 84 85 while (count--) { 86 if (refcount_release(&kref->refcount.counter)) { 87 rel(kref); 88 return 1; 89 } 90 } 91 return 0; 92} 93 94static inline int __must_check 95kref_get_unless_zero(struct kref *kref) 96{ 97 98 return atomic_add_unless(&kref->refcount, 1, 0); 99} 100 101static inline int kref_put_mutex(struct kref *kref, 102 void (*release)(struct kref *kref), struct mutex *lock) 103{ 104 WARN_ON(release == NULL); 105 if (unlikely(!atomic_add_unless(&kref->refcount, -1, 1))) { 106 mutex_lock(lock); 107 if (unlikely(!atomic_dec_and_test(&kref->refcount))) { 108 mutex_unlock(lock); 109 return 0; 110 } 111 release(kref); 112 return 1; 113 } 114 return 0; 115} 116 117#endif /* _LINUX_KREF_H_ */ 118