diff options
author | Thomas Hellstrom <thellstrom@vmware.com> | 2010-11-16 09:21:07 -0500 |
---|---|---|
committer | Dave Airlie <airlied@redhat.com> | 2010-11-21 22:25:13 -0500 |
commit | ecf7ace9a8450303a987aa8364e53860cd50e554 (patch) | |
tree | bbad2c5982c3b76462cbee9e15458072bc80055d | |
parent | d6ea88865d3e5b0c62040531310c1f2c6a994f46 (diff) |
kref: Add a kref_sub function
Makes it possible to optimize batched multiple unrefs.
Initial user will be drivers/gpu/ttm which accumulates unrefs to be
processed outside of atomic code.
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
-rw-r--r-- | include/linux/kref.h | 2 | ||||
-rw-r--r-- | lib/kref.c | 30 |
2 files changed, 32 insertions, 0 deletions
diff --git a/include/linux/kref.h b/include/linux/kref.h index 6cc38fc07ab7..d4a62ab2ee5e 100644 --- a/include/linux/kref.h +++ b/include/linux/kref.h | |||
@@ -24,5 +24,7 @@ struct kref { | |||
24 | void kref_init(struct kref *kref); | 24 | void kref_init(struct kref *kref); |
25 | void kref_get(struct kref *kref); | 25 | void kref_get(struct kref *kref); |
26 | int kref_put(struct kref *kref, void (*release) (struct kref *kref)); | 26 | int kref_put(struct kref *kref, void (*release) (struct kref *kref)); |
27 | int kref_sub(struct kref *kref, unsigned int count, | ||
28 | void (*release) (struct kref *kref)); | ||
27 | 29 | ||
28 | #endif /* _KREF_H_ */ | 30 | #endif /* _KREF_H_ */ |
diff --git a/lib/kref.c b/lib/kref.c index d3d227a08a4b..3efb882b11db 100644 --- a/lib/kref.c +++ b/lib/kref.c | |||
@@ -62,6 +62,36 @@ int kref_put(struct kref *kref, void (*release)(struct kref *kref)) | |||
62 | return 0; | 62 | return 0; |
63 | } | 63 | } |
64 | 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 | |||
65 | EXPORT_SYMBOL(kref_init); | 94 | EXPORT_SYMBOL(kref_init); |
66 | EXPORT_SYMBOL(kref_get); | 95 | EXPORT_SYMBOL(kref_get); |
67 | EXPORT_SYMBOL(kref_put); | 96 | EXPORT_SYMBOL(kref_put); |
97 | EXPORT_SYMBOL(kref_sub); | ||