Release 4.18 lib/dec_and_lock.c
// SPDX-License-Identifier: GPL-2.0
#include <linux/export.h>
#include <linux/spinlock.h>
#include <linux/atomic.h>
/*
* This is an implementation of the notion of "decrement a
* reference count, and return locked if it decremented to zero".
*
* NOTE NOTE NOTE! This is _not_ equivalent to
*
* if (atomic_dec_and_test(&atomic)) {
* spin_lock(&lock);
* return 1;
* }
* return 0;
*
* because the spin-lock and the decrement must be
* "atomic".
*/
int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock)
{
/* Subtract 1 from counter unless that drops it to 0 (ie. it was 1) */
if (atomic_add_unless(atomic, -1, 1))
return 0;
/* Otherwise do it the slow way */
spin_lock(lock);
if (atomic_dec_and_test(atomic))
return 1;
spin_unlock(lock);
return 0;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Linus Torvalds (pre-git) | 24 | 45.28% | 1 | 33.33% |
| David S. Miller | 23 | 43.40% | 1 | 33.33% |
| Nicholas Piggin | 6 | 11.32% | 1 | 33.33% |
| Total | 53 | 100.00% | 3 | 100.00% |
EXPORT_SYMBOL(_atomic_dec_and_lock);
int _atomic_dec_and_lock_irqsave(atomic_t *atomic, spinlock_t *lock,
unsigned long *flags)
{
/* Subtract 1 from counter unless that drops it to 0 (ie. it was 1) */
if (atomic_add_unless(atomic, -1, 1))
return 0;
/* Otherwise do it the slow way */
spin_lock_irqsave(lock, *flags);
if (atomic_dec_and_test(atomic))
return 1;
spin_unlock_irqrestore(lock, *flags);
return 0;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Anna-Maria Gleixner | 64 | 100.00% | 1 | 100.00% |
| Total | 64 | 100.00% | 1 | 100.00% |
EXPORT_SYMBOL(_atomic_dec_and_lock_irqsave);
Overall Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Anna-Maria Gleixner | 69 | 50.00% | 1 | 11.11% |
| Linus Torvalds (pre-git) | 29 | 21.01% | 1 | 11.11% |
| David S. Miller | 23 | 16.67% | 1 | 11.11% |
| Linus Torvalds | 7 | 5.07% | 2 | 22.22% |
| Nicholas Piggin | 7 | 5.07% | 1 | 11.11% |
| Greg Kroah-Hartman | 1 | 0.72% | 1 | 11.11% |
| Arun Sharma | 1 | 0.72% | 1 | 11.11% |
| Paul Gortmaker | 1 | 0.72% | 1 | 11.11% |
| Total | 138 | 100.00% | 9 | 100.00% |
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