mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 17:30:02 +00:00
![Kees Cook](/assets/img/avatar_default.png)
CONFIG_REFCOUNT_FULL=y (correctly) does not provide a refcount_sub(),
which should not be part of proper refcount design patterns.
Remove the erroneous extern and the later !CONFIG_REFCOUNT_FULL
accidental implementation.
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Elena Reshetova <elena.reshetova@intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 29dee3c03a
("locking/refcounts: Out-of-line everything")
Link: http://lkml.kernel.org/r/20170701180129.GA17405@beast
Signed-off-by: Ingo Molnar <mingo@kernel.org>
97 lines
2.5 KiB
C
97 lines
2.5 KiB
C
#ifndef _LINUX_REFCOUNT_H
|
|
#define _LINUX_REFCOUNT_H
|
|
|
|
#include <linux/atomic.h>
|
|
#include <linux/mutex.h>
|
|
#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);
|
|
}
|
|
|
|
#ifdef CONFIG_REFCOUNT_FULL
|
|
extern __must_check bool refcount_add_not_zero(unsigned int i, refcount_t *r);
|
|
extern void refcount_add(unsigned int i, refcount_t *r);
|
|
|
|
extern __must_check bool refcount_inc_not_zero(refcount_t *r);
|
|
extern void refcount_inc(refcount_t *r);
|
|
|
|
extern __must_check bool refcount_sub_and_test(unsigned int i, refcount_t *r);
|
|
|
|
extern __must_check bool refcount_dec_and_test(refcount_t *r);
|
|
extern void refcount_dec(refcount_t *r);
|
|
#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_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);
|
|
|
|
#endif /* _LINUX_REFCOUNT_H */
|