atomic_add
#define atomic_inc(p) atomic_add(1, p)
atomic_add(diff, &dev->_vblank_count[crtc]);
atomic_add(npages, &dev->mdev->priv.reg_pages);
atomic_add(mb->len, &ssk->rcv_nxt);
atomic_add(mb->m_pkthdr.len, &ssk->rcv_nxt);
atomic_add(copied, &ssk->rcv_nxt);