RBIO_RMW_LOCKED_BIT
set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
if (test_bit(RBIO_RMW_LOCKED_BIT, &last->flags) ||
test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags))
!test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags)) {
clear_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);