diff options
Diffstat (limited to 'lib/kref.c')
| -rw-r--r-- | lib/kref.c | 97 |
1 files changed, 0 insertions, 97 deletions
diff --git a/lib/kref.c b/lib/kref.c deleted file mode 100644 index 3efb882b11db..000000000000 --- a/lib/kref.c +++ /dev/null | |||
| @@ -1,97 +0,0 @@ | |||
| 1 | /* | ||
| 2 | * kref.c - library routines for handling generic reference counted objects | ||
| 3 | * | ||
| 4 | * Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com> | ||
| 5 | * Copyright (C) 2004 IBM Corp. | ||
| 6 | * | ||
| 7 | * based on lib/kobject.c which was: | ||
| 8 | * Copyright (C) 2002-2003 Patrick Mochel <mochel@osdl.org> | ||
| 9 | * | ||
| 10 | * This file is released under the GPLv2. | ||
| 11 | * | ||
| 12 | */ | ||
| 13 | |||
| 14 | #include <linux/kref.h> | ||
| 15 | #include <linux/module.h> | ||
| 16 | #include <linux/slab.h> | ||
| 17 | |||
| 18 | /** | ||
| 19 | * kref_init - initialize object. | ||
| 20 | * @kref: object in question. | ||
| 21 | */ | ||
| 22 | void kref_init(struct kref *kref) | ||
| 23 | { | ||
| 24 | atomic_set(&kref->refcount, 1); | ||
| 25 | smp_mb(); | ||
| 26 | } | ||
| 27 | |||
| 28 | /** | ||
| 29 | * kref_get - increment refcount for object. | ||
| 30 | * @kref: object. | ||
| 31 | */ | ||
| 32 | void kref_get(struct kref *kref) | ||
| 33 | { | ||
| 34 | WARN_ON(!atomic_read(&kref->refcount)); | ||
| 35 | atomic_inc(&kref->refcount); | ||
| 36 | smp_mb__after_atomic_inc(); | ||
| 37 | } | ||
| 38 | |||
| 39 | /** | ||
| 40 | * kref_put - decrement refcount for object. | ||
| 41 | * @kref: object. | ||
| 42 | * @release: pointer to the function that will clean up the object when the | ||
| 43 | * last reference to the object is released. | ||
| 44 | * This pointer is required, and it is not acceptable to pass kfree | ||
| 45 | * in as this function. | ||
| 46 | * | ||
| 47 | * Decrement the refcount, and if 0, call release(). | ||
| 48 | * Return 1 if the object was removed, otherwise return 0. Beware, if this | ||
| 49 | * function returns 0, you still can not count on the kref from remaining in | ||
| 50 | * memory. Only use the return value if you want to see if the kref is now | ||
| 51 | * gone, not present. | ||
| 52 | */ | ||
| 53 | int kref_put(struct kref *kref, void (*release)(struct kref *kref)) | ||
| 54 | { | ||
| 55 | WARN_ON(release == NULL); | ||
| 56 | WARN_ON(release == (void (*)(struct kref *))kfree); | ||
| 57 | |||
| 58 | if (atomic_dec_and_test(&kref->refcount)) { | ||
| 59 | release(kref); | ||
| 60 | return 1; | ||
| 61 | } | ||
| 62 | return 0; | ||
| 63 | } | ||
| 64 | |||
| 65 | |||
| 66 | /** | ||
| 67 | * kref_sub - subtract a number of refcounts for object. | ||
| 68 | * @kref: object. | ||
| 69 | * @count: Number of recounts to subtract. | ||
| 70 | * @release: pointer to the function that will clean up the object when the | ||
| 71 | * last reference to the object is released. | ||
| 72 | * This pointer is required, and it is not acceptable to pass kfree | ||
| 73 | * in as this function. | ||
| 74 | * | ||
| 75 | * Subtract @count from the refcount, and if 0, call release(). | ||
| 76 | * Return 1 if the object was removed, otherwise return 0. Beware, if this | ||
| 77 | * function returns 0, you still can not count on the kref from remaining in | ||
| 78 | * memory. Only use the return value if you want to see if the kref is now | ||
| 79 | * gone, not present. | ||
| 80 | */ | ||
| 81 | int kref_sub(struct kref *kref, unsigned int count, | ||
| 82 | void (*release)(struct kref *kref)) | ||
| 83 | { | ||
| 84 | WARN_ON(release == NULL); | ||
| 85 | WARN_ON(release == (void (*)(struct kref *))kfree); | ||
| 86 | |||
| 87 | if (atomic_sub_and_test((int) count, &kref->refcount)) { | ||
| 88 | release(kref); | ||
| 89 | return 1; | ||
| 90 | } | ||
| 91 | return 0; | ||
| 92 | } | ||
| 93 | |||
| 94 | EXPORT_SYMBOL(kref_init); | ||
| 95 | EXPORT_SYMBOL(kref_get); | ||
| 96 | EXPORT_SYMBOL(kref_put); | ||
| 97 | EXPORT_SYMBOL(kref_sub); | ||
