inc_unless_negative
cat <<EOF
static __always_inline bool
${arch}${atomic}_inc_unless_negative(${atomic}_t *v)
{
${int} c = ${arch}${atomic}_read(v);
do {
if (unlikely(c < 0))
return false;
} while (!${arch}${atomic}_try_cmpxchg(v, &c, c + 1));
return true;
}
EOF