LINUX_KQ_FLAG_HAS_READ
filp->f_kqflags |= LINUX_KQ_FLAG_HAS_READ;
LINUX_KQ_FLAG_HAS_READ | LINUX_KQ_FLAG_HAS_WRITE);
linux_file_kqfilter_poll(filp, LINUX_KQ_FLAG_HAS_READ);
LINUX_KQ_FLAG_HAS_READ | LINUX_KQ_FLAG_HAS_WRITE);