/**
* blocking_notifier_chain_cond_register - Cond add notifier to a blocking notifier chain
* @nh: Pointer to head of the blocking notifier chain
* @n: New entry in notifier chain
*
* Adds a notifier to a blocking notifier chain, only if not already
* present in the chain.
* Must be called in process context.
*
* Currently always returns zero.
*/
int blocking_notifier_chain_cond_register(struct blocking_notifier_head *nh,
struct notifier_block *n)
{
int ret;
down_write(&nh->rwsem);
ret = notifier_chain_cond_register(&nh->head, n);
up_write(&nh->rwsem);
return ret;
}
int vmm_blocking_notifier_cond_register(struct vmm_blocking_notifier_chain *nc,
struct vmm_notifier_block *n)
{
int ret;
vmm_semaphore_down(&nc->rwsem);
ret = notifier_chain_cond_register(&nc->head, n);
vmm_semaphore_up(&nc->rwsem);
return ret;
}
