1 #include <linux/module.h>
2 #include <linux/spinlock.h>
3 #include <asm/atomic.h>
4 #include <asm/system.h>
7 * This is an implementation of the notion of "decrement a
8 * reference count, and return locked if it decremented to zero".
10 * This implementation can be used on any architecture that
11 * has a cmpxchg, and where atomic->value is an int holding
12 * the value of the atomic (i.e. the high bits aren't used
13 * for a lock or anything like that).
15 int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock)
21 counter = atomic_read(atomic);
22 newcount = counter - 1;
24 break; /* do it the slow way */
26 newcount = cmpxchg(&atomic->counter, counter, newcount);
27 if (newcount == counter)
32 if (atomic_dec_and_test(atomic))
38 EXPORT_SYMBOL(_atomic_dec_and_lock);