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author | Dominik Sliwa <dominik.sliwa@toradex.com> | 2019-03-04 12:01:54 +0100 |
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committer | Dominik Sliwa <dominik.sliwa@toradex.com> | 2019-03-04 12:01:54 +0100 |
commit | 348fa3f6871f56a37dcd16c99ca98118c6d79a38 (patch) | |
tree | 6fcae7785bae4ffb838fd6549f7d01ba6abf0763 /include/linux/backport-refcount.h |
Backports v4.19.24
Backports generated by toradex backports 515a1fa55cda2b1d952872e1786857481bd54fcc
against mainline kernel tag v4.19.24
Signed-off-by: Dominik Sliwa <dominik.sliwa@toradex.com>
Diffstat (limited to 'include/linux/backport-refcount.h')
-rw-r--r-- | include/linux/backport-refcount.h | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/include/linux/backport-refcount.h b/include/linux/backport-refcount.h new file mode 100644 index 0000000..e28cce2 --- /dev/null +++ b/include/linux/backport-refcount.h @@ -0,0 +1,118 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_REFCOUNT_H +#define _LINUX_REFCOUNT_H + +#include <linux/atomic.h> +#include <linux/compiler.h> +#include <linux/spinlock_types.h> + +struct mutex; + +/** + * struct 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); +} + +extern __must_check bool refcount_add_not_zero_checked(unsigned int i, refcount_t *r); +extern void refcount_add_checked(unsigned int i, refcount_t *r); + +extern __must_check bool refcount_inc_not_zero_checked(refcount_t *r); +extern void refcount_inc_checked(refcount_t *r); + +extern __must_check bool refcount_sub_and_test_checked(unsigned int i, refcount_t *r); + +extern __must_check bool refcount_dec_and_test_checked(refcount_t *r); +extern void refcount_dec_checked(refcount_t *r); + +#ifdef CONFIG_REFCOUNT_FULL + +#define refcount_add_not_zero refcount_add_not_zero_checked +#define refcount_add refcount_add_checked + +#define refcount_inc_not_zero refcount_inc_not_zero_checked +#define refcount_inc refcount_inc_checked + +#define refcount_sub_and_test refcount_sub_and_test_checked + +#define refcount_dec_and_test refcount_dec_and_test_checked +#define refcount_dec refcount_dec_checked + +#else +# ifdef CONFIG_ARCH_HAS_REFCOUNT +# include <asm/refcount.h> +# else +static inline __must_check bool refcount_add_not_zero(unsigned int i, refcount_t *r) +{ + return atomic_add_unless(&r->refs, i, 0); +} + +static inline void refcount_add(unsigned int i, refcount_t *r) +{ + atomic_add(i, &r->refs); +} + +static inline __must_check bool refcount_inc_not_zero(refcount_t *r) +{ + return atomic_add_unless(&r->refs, 1, 0); +} + +static inline void refcount_inc(refcount_t *r) +{ + atomic_inc(&r->refs); +} + +static inline __must_check bool refcount_sub_and_test(unsigned int i, refcount_t *r) +{ + return atomic_sub_and_test(i, &r->refs); +} + +static inline __must_check bool refcount_dec_and_test(refcount_t *r) +{ + return atomic_dec_and_test(&r->refs); +} + +static inline void refcount_dec(refcount_t *r) +{ + atomic_dec(&r->refs); +} +# endif /* !CONFIG_ARCH_HAS_REFCOUNT */ +#endif /* CONFIG_REFCOUNT_FULL */ + +extern __must_check bool refcount_dec_if_one(refcount_t *r); +extern __must_check bool refcount_dec_not_one(refcount_t *r); +extern __must_check bool refcount_dec_and_mutex_lock(refcount_t *r, struct mutex *lock); +extern __must_check bool refcount_dec_and_lock(refcount_t *r, spinlock_t *lock); +extern __must_check bool refcount_dec_and_lock_irqsave(refcount_t *r, + spinlock_t *lock, + unsigned long *flags); +#endif /* _LINUX_REFCOUNT_H */ |