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| author | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2017-05-30 05:54:21 +0300 |
|---|---|---|
| committer | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2017-05-30 05:54:21 +0300 |
| commit | d8f797c60661a90ee26ca9330cf85ede9aa2ec17 (patch) | |
| tree | 5038609885fc3e4cb7f329d974875ac4411c6af5 /include/linux/refcount.h | |
| parent | 8fd708157a592a376c4d0b3b2ba23b9e9f79caa5 (diff) | |
| parent | 5ed02dbb497422bf225783f46e6eadd237d23d6b (diff) | |
| download | linux-d8f797c60661a90ee26ca9330cf85ede9aa2ec17.tar.xz | |
Merge tag 'v4.12-rc3' into next
Sync with mainline to bring in changes in platform drovers dropping
calls to sparse_keymap_free() so that we can remove it for good.
Diffstat (limited to 'include/linux/refcount.h')
| -rw-r--r-- | include/linux/refcount.h | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/include/linux/refcount.h b/include/linux/refcount.h index 0023fee4bbbc..b34aa649d204 100644 --- a/include/linux/refcount.h +++ b/include/linux/refcount.h @@ -6,17 +6,36 @@ #include <linux/spinlock.h> #include <linux/kernel.h> +/** + * refcount_t - variant of atomic_t specialized for reference counts + * @refs: atomic_t counter field + * + * The counter saturates at UINT_MAX and will not move once + * there. This avoids wrapping the counter and causing 'spurious' + * use-after-free bugs. + */ typedef struct refcount_struct { atomic_t refs; } refcount_t; #define REFCOUNT_INIT(n) { .refs = ATOMIC_INIT(n), } +/** + * refcount_set - set a refcount's value + * @r: the refcount + * @n: value to which the refcount will be set + */ static inline void refcount_set(refcount_t *r, unsigned int n) { atomic_set(&r->refs, n); } +/** + * refcount_read - get a refcount's value + * @r: the refcount + * + * Return: the refcount's value + */ static inline unsigned int refcount_read(const refcount_t *r) { return atomic_read(&r->refs); |
