linux-kernel - Re: [PATCH v1 3/7] test_hexdump: go through all possible lengths of buffer

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Date:	Thu, 19 Nov 2015 11:07:16 +0100
From:	Rasmus Villemoes <linux@...musvillemoes.dk>
To:	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 3/7] test_hexdump: go through all possible lengths of buffer

On Wed, Nov 11 2015, Andy Shevchenko <andriy.shevchenko@...ux.intel.com> wrote:

> When test for overflow do iterate the buffer length in a range
> 0 .. BUF_SIZE.
>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> ---
>  lib/test_hexdump.c | 20 ++++++++++----------
>  1 file changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/lib/test_hexdump.c b/lib/test_hexdump.c
> index ed7c6a7..15a6440 100644
> --- a/lib/test_hexdump.c
> +++ b/lib/test_hexdump.c
> @@ -126,17 +126,17 @@ static void __init test_hexdump_set(int rowsize, bool ascii)
>  	test_hexdump(len, rowsize, 1, ascii);
>  }
>  
> -static void __init test_hexdump_overflow(bool ascii)
> +static void __init test_hexdump_overflow(size_t buflen, bool ascii)
>  {
> -	char buf[56];
> +	char buf[TEST_HEXDUMP_BUF_SIZE];
>  	const char *t = test_data_1_le[0];
> -	size_t l = get_random_int() % sizeof(buf);
> +	size_t l = buflen;
>  	bool a;
>  	int e, r;
>  
>  	memset(buf, ' ', sizeof(buf));
>  
> -	r = hex_dump_to_buffer(data_b, 1, 16, 1, buf, l, ascii);
> +	r = hex_dump_to_buffer(data_b, 1, 16, 1, buf, buflen, ascii);
>  
>  	if (ascii)
>  		e = 50;
> @@ -144,7 +144,7 @@ static void __init test_hexdump_overflow(bool ascii)
>  		e = 2;
>  	buf[e + 2] = '\0';
>  
> -	if (!l) {
> +	if (!buflen) {
>  		a = r == e && buf[0] == ' ';
>  	} else if (l < 3) {
>  		a = r == e && buf[0] == '\0';


Why keep the variable l when it is just a synonym for the new
parameter buflen? It is quite confusing that you change some but not
all occurrences of l to buflen. If you want to make the diff minimal
but still have a descriptive parameter name, just keep the 'size_t l =
buflen;' assignment and don't otherwise refer to buflen. But I think
it's better to eliminate 'l' and just change everything to
buflen. Don't mix the two approaches, though.

Rasmus
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