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

[Daniel K.]

Namhyung Kim wrote:
> 2010-10-02 (í), 12:57 +0900, Namhyung Kim:
> > 2010-10-02 (í), 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.
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