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

From: Paul Crawford
Date: Thu Feb 23 2017 - 04:50:42 EST

On 23/02/17 07:24, 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.

This was one issue raised with the OpenSSL review where a lack of brackets made some coding errors less obvious and in the changes was down as applying "KNF format the whole source tree"

Probably the easiest fix is to use some tool like "indent --linux-style" though I am not completely sure that option is perfect.

Certainly if you have code with an odd mix of styles it is much harder to read, and ultimately source code is for *humans* to understand. So enforcing a consistent style, even if it is not your own style, makes it much easier to follow!

Just my 2p worth.

Dr. Paul S. Crawford
c/o Satellite Station
University of Dundee
Small's Wynd, Dundee, DD1 4HN
Email: psc@xxxxxxxxxxxxxxxx
Tel: +44 (0)1382 38 4687
The University of Dundee is a Scottish Registered Charity, No. SC015096