Re: [PATCH RESEND v3 09/24] ptrace: cleanup arch_ptrace() on frv

["Daniel K." <dk@uw.no>]

Namhyung Kim wrote:
> 2010-10-02 (토), 12:57 +0900, Namhyung Kim:
>> 2010-10-02 (토), 03:18 +0000, Daniel K.:
>>> Namhyung Kim wrote:
>>>>       case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
>>>>             ret = -EIO;
>>> -             if ((addr & 3) || addr < 0)
>>> +             if (addr & 3)
>>>                     break;
>>>
>>>> -		ret = 0;
>>>> -		switch (addr >> 2) {
>>>> +		switch (regno) {
>>>>  		case 0 ... PT__END - 1:
>>>> -			ret = put_reg(child, addr >> 2, data);
>>>> -			break;
>>>> -
>>>> -		default:
>>>> -			ret = -EIO;
>>>> +			ret = put_reg(child, regno, data);
>>>>  			break;
>>>>  		}
>>>>  		break;
>>> With this, you remove the default case, and no longer return -EIO in the
>>> cases of PT__END + n, as in the PTRACE_PEEKUSR section above.
>>>
>>> This is a change of behaviour as far as I can tell, and not just a cleanup.
> 
> It would not be a change of behaviour. Because 'ret' was initialized
> with -EIO and only changed in the switch case. So assignment before
> switch can be removed and then will return -EIO in default case.

You are right, I was thrown by the piles of needless code here.

In fact, the whole switch can now be replaced with:

	if (regno < PT__END)
		ret = put_reg(child, regno, data);

but it is perhaps better to use the switch-style, for symmetry with
the PTRACE_PEEKUSR case directly above it?


Sorry to cause alarm.


Daniel K.