提交 c3ac7cf1 编写于 作者: P Paul E. McKenney

rcu: Add rcu_pointer_handoff()

This commit adds an rcu_pointer_handoff() that is intended to mark
situations where a structure's protection transitions from RCU to some
other mechanism (locking, reference counting, whatever).  These markings
should allow external tools to more easily spot bugs involving leaking
pointers out of RCU read-side critical sections.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
上级 c34d2f41
......@@ -812,6 +812,28 @@ static inline void rcu_preempt_sleep_check(void)
*/
#define rcu_dereference_sched(p) rcu_dereference_sched_check(p, 0)
/**
* rcu_pointer_handoff() - Hand off a pointer from RCU to other mechanism
* @p: The pointer to hand off
*
* This is simply an identity function, but it documents where a pointer
* is handed off from RCU to some other synchronization mechanism, for
* example, reference counting or locking. In C11, it would map to
* kill_dependency(). It could be used as follows:
*
* rcu_read_lock();
* p = rcu_dereference(gp);
* long_lived = is_long_lived(p);
* if (long_lived) {
* if (!atomic_inc_not_zero(p->refcnt))
* long_lived = false;
* else
* p = rcu_pointer_handoff(p);
* }
* rcu_read_unlock();
*/
#define rcu_pointer_handoff(p) (p)
/**
* rcu_read_lock() - mark the beginning of an RCU read-side critical section
*
......
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