eventfd_ctx_do_read
eventfd_ctx_do_read(irqfd->irqfd_eventfd_ctx, &cnt);
eventfd_ctx_do_read(virqfd->eventfd, &cnt);
eventfd_ctx_do_read(kirqfd->eventfd, &cnt);
EXPORT_SYMBOL_GPL(eventfd_ctx_do_read);
eventfd_ctx_do_read(ctx, cnt);
eventfd_ctx_do_read(ctx, &ucnt);
void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt);
eventfd_ctx_do_read(irqfd->eventfd, &cnt);