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