atomic_xchg
#define atomic_long_xchg(v, n) atomic_xchg(v, n)
if (atomic_xchg(&rdev->ih.lock, 1))
if (atomic_xchg(&rdev->ih.lock, 1))
if (atomic_xchg(&rdev->ih.lock, 1))
if (atomic_xchg(&rdev->ih.lock, 1))