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 #ifndef _LINUXKPI_LINUX_KREF_H_ 31 #define _LINUXKPI_LINUX_KREF_H_ 32 33 #include <sys/types.h> 34 #include <sys/refcount.h> 35 36 #include <linux/compiler.h> 37 #include <linux/kernel.h> 38 #include <linux/mutex.h> 39 #include <linux/refcount.h> 40 41 #include <asm/atomic.h> 42 43 struct kref { 44 refcount_t refcount; 45 }; 46 47 static inline void 48 kref_init(struct kref *kref) 49 { 50 51 refcount_init((uint32_t *)&kref->refcount, 1); 52 } 53 54 static inline unsigned int 55 kref_read(const struct kref *kref) 56 { 57 58 return (refcount_load(__DECONST(u_int32_t *, &kref->refcount))); 59 } 60 61 static inline void 62 kref_get(struct kref *kref) 63 { 64 65 refcount_acquire((uint32_t *)&kref->refcount); 66 } 67 68 static inline int 69 kref_put(struct kref *kref, void (*rel)(struct kref *kref)) 70 { 71 72 if (refcount_release((uint32_t *)&kref->refcount)) { 73 rel(kref); 74 return 1; 75 } 76 return 0; 77 } 78 79 static inline int 80 kref_put_lock(struct kref *kref, void (*rel)(struct kref *kref), 81 spinlock_t *lock) 82 { 83 84 if (refcount_release((uint32_t *)&kref->refcount)) { 85 spin_lock(lock); 86 rel(kref); 87 return (1); 88 } 89 return (0); 90 } 91 92 static inline int 93 kref_sub(struct kref *kref, unsigned int count, 94 void (*rel)(struct kref *kref)) 95 { 96 97 while (count--) { 98 if (refcount_release((uint32_t *)&kref->refcount)) { 99 rel(kref); 100 return 1; 101 } 102 } 103 return 0; 104 } 105 106 static inline int __must_check 107 kref_get_unless_zero(struct kref *kref) 108 { 109 110 return refcount_acquire_if_not_zero((uint32_t *)&kref->refcount); 111 } 112 113 static inline int kref_put_mutex(struct kref *kref, 114 void (*release)(struct kref *kref), struct mutex *lock) 115 { 116 WARN_ON(release == NULL); 117 if (unlikely(!refcount_release_if_not_last((uint32_t *)&kref->refcount))) { 118 mutex_lock(lock); 119 if (unlikely(!refcount_release((uint32_t *)&kref->refcount))) { 120 mutex_unlock(lock); 121 return 0; 122 } 123 release(kref); 124 return 1; 125 } 126 return 0; 127 } 128 129 #endif /* _LINUXKPI_LINUX_KREF_H_ */ 130