linux-kernel - Re: [PATCH v1 4/7] test_hexdump: replace magic numbers by their meaning

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Date:	Fri, 20 Nov 2015 18:56:28 +0200
From:	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:	Rasmus Villemoes <linux@...musvillemoes.dk>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 4/7] test_hexdump: replace magic numbers by their
 meaning

On Thu, 2015-11-19 at 11:08 +0100, Rasmus Villemoes wrote:
> On Wed, Nov 11 2015, Andy Shevchenko <andriy.shevchenko@...ux.intel.c
> om> wrote:
> 
> > The magic numbers of the length are converted to their actual
> > meaning, such as
> > end of the buffer with and without ASCII part.
> > 
> > We don't touch the rest magic constants that will be removed in the
> > following
> > commits.
> > 
> > Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> > ---
> >  lib/test_hexdump.c | 13 +++++++++----
> >  1 file changed, 9 insertions(+), 4 deletions(-)
> > 
> > diff --git a/lib/test_hexdump.c b/lib/test_hexdump.c
> > index 15a6440..a3e3b01 100644
> > --- a/lib/test_hexdump.c
> > +++ b/lib/test_hexdump.c
> > @@ -130,18 +130,23 @@ static void __init
> > test_hexdump_overflow(size_t buflen, bool ascii)
> >  {
> >  	char buf[TEST_HEXDUMP_BUF_SIZE];
> >  	const char *t = test_data_1_le[0];
> > +	size_t len = 1;
> >  	size_t l = buflen;
> > +	int rs = 16, gs = 1;
> > +	int ae, he, e, r;
> >  	bool a;
> > -	int e, r;
> >  
> >  	memset(buf, ' ', sizeof(buf));
> >  
> > -	r = hex_dump_to_buffer(data_b, 1, 16, 1, buf, buflen,
> > ascii);
> > +	r = hex_dump_to_buffer(data_b, len, rs, gs, buf, buflen,
> > ascii);
> > +
> > +	ae = rs * 2 /* hex */ + rs / gs /* spaces */ + 1 /* space
> > */ + len /* ascii */;
> > +	he = (gs * 2 /* hex */ + 1 /* space */) * len / gs - 1 /*
> > no trailing space */;
> 
> This computation seems to rely on len being an exact multiple of gs -
> which of course it is in this case. hex_dump_to_buffer also enforces
> it by setting groupsize to 1 when it's not the case, but that doesn't
> really help us here. So maybe an extra comment would be justified.

Agree. A comment would be nice to have.

> 
> Rasmus

-- 
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Intel Finland Oy

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