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(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
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1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283// 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;}
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;}EXPORT_SYMBOL(_atomic_dec_and_lock_irqsave);
int atomic_dec_and_raw_lock(atomic_t *atomic, raw_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 */ raw_spin_lock(lock); if (atomic_dec_and_test(atomic)) return 1; raw_spin_unlock(lock); return 0;}EXPORT_SYMBOL(atomic_dec_and_raw_lock);
int _atomic_dec_and_raw_lock_irqsave(atomic_t *atomic, raw_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 */ raw_spin_lock_irqsave(lock, *flags); if (atomic_dec_and_test(atomic)) return 1; raw_spin_unlock_irqrestore(lock, *flags); return 0;}EXPORT_SYMBOL(_atomic_dec_and_raw_lock_irqsave);