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 François 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 * $FreeBSD$ 31 */ 32 #ifndef _LINUXKPI_LINUX_KREF_H_ 33 #define _LINUXKPI_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 #include <linux/refcount.h> 42 43 #include <asm/atomic.h> 44 45 struct kref { 46 /* XXX In Linux this is a refcount_t */ 47 atomic_t refcount; 48 }; 49 50 static inline void 51 kref_init(struct kref *kref) 52 { 53 54 refcount_init((uint32_t *)&kref->refcount, 1); 55 } 56 57 static inline unsigned int 58 kref_read(const struct kref *kref) 59 { 60 61 return (refcount_load(__DECONST(u_int32_t *, &kref->refcount))); 62 } 63 64 static inline void 65 kref_get(struct kref *kref) 66 { 67 68 refcount_acquire((uint32_t *)&kref->refcount); 69 } 70 71 static inline int 72 kref_put(struct kref *kref, void (*rel)(struct kref *kref)) 73 { 74 75 if (refcount_release((uint32_t *)&kref->refcount)) { 76 rel(kref); 77 return 1; 78 } 79 return 0; 80 } 81 82 static inline int 83 kref_put_lock(struct kref *kref, void (*rel)(struct kref *kref), 84 spinlock_t *lock) 85 { 86 87 if (refcount_release((uint32_t *)&kref->refcount)) { 88 spin_lock(lock); 89 rel(kref); 90 return (1); 91 } 92 return (0); 93 } 94 95 static inline int 96 kref_sub(struct kref *kref, unsigned int count, 97 void (*rel)(struct kref *kref)) 98 { 99 100 while (count--) { 101 if (refcount_release((uint32_t *)&kref->refcount)) { 102 rel(kref); 103 return 1; 104 } 105 } 106 return 0; 107 } 108 109 static inline int __must_check 110 kref_get_unless_zero(struct kref *kref) 111 { 112 113 return refcount_acquire_if_not_zero((uint32_t *)&kref->refcount); 114 } 115 116 static inline int kref_put_mutex(struct kref *kref, 117 void (*release)(struct kref *kref), struct mutex *lock) 118 { 119 WARN_ON(release == NULL); 120 if (unlikely(!refcount_release_if_not_last((uint32_t *)&kref->refcount))) { 121 mutex_lock(lock); 122 if (unlikely(!refcount_release((uint32_t *)&kref->refcount))) { 123 mutex_unlock(lock); 124 return 0; 125 } 126 release(kref); 127 return 1; 128 } 129 return 0; 130 } 131 132 #endif /* _LINUXKPI_LINUX_KREF_H_ */ 133