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 _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 <asm/atomic.h> 40 41 struct kref { 42 atomic_t refcount; 43 }; 44 45 static inline void 46 kref_init(struct kref *kref) 47 { 48 49 refcount_init(&kref->refcount.counter, 1); 50 } 51 52 static inline void 53 kref_get(struct kref *kref) 54 { 55 56 refcount_acquire(&kref->refcount.counter); 57 } 58 59 static inline int 60 kref_put(struct kref *kref, void (*rel)(struct kref *kref)) 61 { 62 63 if (refcount_release(&kref->refcount.counter)) { 64 rel(kref); 65 return 1; 66 } 67 return 0; 68 } 69 70 static inline int 71 kref_sub(struct kref *kref, unsigned int count, 72 void (*rel)(struct kref *kref)) 73 { 74 75 while (count--) { 76 if (refcount_release(&kref->refcount.counter)) { 77 rel(kref); 78 return 1; 79 } 80 } 81 return 0; 82 } 83 84 static inline int __must_check 85 kref_get_unless_zero(struct kref *kref) 86 { 87 88 return atomic_add_unless(&kref->refcount, 1, 0); 89 } 90 91 #endif /* _LINUX_KREF_H_ */ 92