Re: [PATCH v4 01/17] x86/mpx: Do not use SIB index if index points to R/ESP

From	Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v4 01/17] x86/mpx: Do not use SIB index if index points to R/ESP
Date	2017-02-24 03:50 +0100
Message-ID	<tee7f-1We-1@gated-at.bofh.it> (permalink)
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On Thu, 2017-02-23 at 18:33 -0800, Joe Perches wrote:
> On Thu, 2017-02-23 at 14:17 -0800, Ricardo Neri wrote:
> > On Thu, 2017-02-23 at 08:24 +0100, Peter Zijlstra wrote:
> > > On Wed, Feb 22, 2017 at 10:36:50PM -0800, Ricardo Neri wrote:
> > > > +			/*
> > > > +			 * A negative offset generally means a error, except
> > > > +			 * -EDOM, which means that the contents of the register
> > > > +			 * should not be used as index.
> > > > +			 */
> > > >  			if (indx_offset < 0)
> > > > -				goto out_err;
> > > > +				if (indx_offset == -EDOM)
> > > > +					indx = 0;
> > > > +				else
> > > > +					goto out_err;
> > > > +			else
> > > > +				indx = regs_get_register(regs, indx_offset);
> > > 
> > > Kernel coding style requires more brackets than are strictly required by
> > > C, any block longer than 1 line needs then. Also, if one leg of a
> > > conditional needs them, then they should be on both legs.
> > > 
> > > Your code has many such instances, please change them all.
> > 
> > Will do. Sorry for the noise. These instances escaped the checkpatch
> > script.
> 
> Also, this code would read better with the inner test
> reversed or done first
> 
> 		if (indx_offset < 0) {
> 			if (indx_offset != -EDOM)
> 				goto out_err;
> 			indx = 0;
> 		} else {
> 			indx = regs_get_register(etc...)
> 		}
> 
> or
> 		if (indx_offset == -EDOM)
> 			indx = 0;
> 		else if (indx_offset < 0)
> 			goto err;
> 		else
> 			indx = regs_get_register(etc...)
> 
> The compiler should generate the same code in any
> case, but either could improve reader understanding.

I agree! I will change it with your clever solution.

Thanks and BR,
Ricardo

Thread

[PATCH v4 01/17] x86/mpx: Do not use SIB index if index points to R/ESP Ricardo Neri <ricardo.neri-calderon@linux.intel.com> - 2017-02-23 07:50 +0100
  Re: [PATCH v4 01/17] x86/mpx: Do not use SIB index if index points  to R/ESP Peter Zijlstra <peterz@infradead.org> - 2017-02-23 08:30 +0100
    Re: [PATCH v4 01/17] x86/mpx: Do not use SIB index if index points to  R/ESP Paul Crawford <psc@sat.dundee.ac.uk> - 2017-02-23 11:00 +0100
    Re: [PATCH v4 01/17] x86/mpx: Do not use SIB index if index points  to R/ESP Ricardo Neri <ricardo.neri-calderon@linux.intel.com> - 2017-02-23 23:20 +0100
      Re: [PATCH v4 01/17] x86/mpx: Do not use SIB index if index points  to R/ESP Joe Perches <joe@perches.com> - 2017-02-24 03:40 +0100
        Re: [PATCH v4 01/17] x86/mpx: Do not use SIB index if index points  to R/ESP Ricardo Neri <ricardo.neri-calderon@linux.intel.com> - 2017-02-24 03:50 +0100
        Re: [PATCH v4 01/17] x86/mpx: Do not use SIB index if index points to R/ESP Adan Hawthorn <adanhawthorn@gmail.com> - 2017-02-24 16:10 +0100
        Re: [PATCH v4 01/17] x86/mpx: Do not use SIB index if index points  to R/ESP Ricardo Neri <ricardo.neri-calderon@linux.intel.com> - 2017-02-24 20:10 +0100

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