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