This is actually contrary to Linux kernel "good style". Functions should be short and understandable. Comments should be on the top of the function, describing what the function is for. Comments describing variables in functions are discouraged.
This brings to mind the Orwell essay on language usage[1]: Break any of these rules sooner than say anything outright barbarous.
IMO having "three = 1" with no immediate context qualifies as barbarous. Yes it would be best to rename the variable, but, failing that, just toss in a freaking comment for common sense's sake.
The code example being discussed has comments sprinkled throughout the functions, and the "good style" / standard also says try to avoid not avoid at all cost. Also, something about blind adherence to rulebooks.
unsigned current_power_of_three = 1;
or something equally verbose. I'd expect such silliness in some enterprisey java code, but I think most people would agree a short explanatory comment is probably the superior choice.