cmpxchg
#define cmpxchg64(...) cmpxchg(__VA_ARGS__)
#define cmpxchg_relaxed(...) cmpxchg(__VA_ARGS__)
prev = cmpxchg(lock, old, new);
prev = cmpxchg(lock, old, new);
prev = cmpxchg(lock, old, new);
prev = cmpxchg(&s->lock->lock, old, new);
prev = cmpxchg(lock, old, DRM_KERNEL_CONTEXT);