atomic: Add atomic_or()

An atomic_or() function is needed by TREE_RCU to avoid deadlock, so
add a generic version.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Paul E. McKenney 2011-05-11 05:33:33 -07:00 committed by Ingo Molnar
parent 29f742f88a
commit 55c2945aa9

View File

@ -34,4 +34,17 @@ static inline int atomic_inc_not_zero_hint(atomic_t *v, int hint)
}
#endif
#ifndef CONFIG_ARCH_HAS_ATOMIC_OR
static inline void atomic_or(int i, atomic_t *v)
{
int old;
int new;
do {
old = atomic_read(v);
new = old | i;
} while (atomic_cmpxchg(v, old, new) != old);
}
#endif /* #ifndef CONFIG_ARCH_HAS_ATOMIC_OR */
#endif /* _LINUX_ATOMIC_H */