Re: [PATCH v3 2/7] lib/hexdump.c: Relax rowsize checks in hex_dump_to_buffer

[Randy Dunlap <rdunlap@infradead.org>]

Hi,
Just a comment style nit below...

On 6/16/19 7:04 PM, Alastair D'Silva wrote:
> From: Alastair D'Silva <alastair@d-silva.org>
> 
> This patch removes the hardcoded row limits and allows for
> other lengths. These lengths must still be a multiple of
> groupsize.
> 
> This allows structs that are not 16/32 bytes to display on
> a single line.
> 
> This patch also expands the self-tests to test row sizes
> up to 64 bytes (though they can now be arbitrarily long).
> 
> Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
> ---
>  lib/hexdump.c      | 48 ++++++++++++++++++++++++++++--------------
>  lib/test_hexdump.c | 52 ++++++++++++++++++++++++++++++++++++++--------
>  2 files changed, 75 insertions(+), 25 deletions(-)
> 
> diff --git a/lib/hexdump.c b/lib/hexdump.c
> index 81b70ed37209..3943507bc0e9 100644
> --- a/lib/hexdump.c
> +++ b/lib/hexdump.c

> @@ -246,17 +248,29 @@ void print_hex_dump(const char *level, const char *prefix_str, int prefix_type,
>  {
>  	const u8 *ptr = buf;
>  	int i, linelen, remaining = len;
> -	unsigned char linebuf[32 * 3 + 2 + 32 + 1];
> +	unsigned char *linebuf;
> +	unsigned int linebuf_len;
>  
> -	if (rowsize != 16 && rowsize != 32)
> -		rowsize = 16;
> +	if (rowsize % groupsize)
> +		rowsize -= rowsize % groupsize;
> +
> +	/* Worst case line length:
> +	 * 2 hex chars + space per byte in, 2 spaces, 1 char per byte in, NULL
> +	 */

According to Documentation/process/coding-style.rst:

The preferred style for long (multi-line) comments is:

.. code-block:: c

	/*
	 * This is the preferred style for multi-line
	 * comments in the Linux kernel source code.
	 * Please use it consistently.
	 *
	 * Description:  A column of asterisks on the left side,
	 * with beginning and ending almost-blank lines.
	 */


except in networking software.


> +	linebuf_len = rowsize * 3 + 2 + rowsize + 1;
> +	linebuf = kzalloc(linebuf_len, GFP_KERNEL);
> +	if (!linebuf) {
> +		printk("%s%shexdump: Could not alloc %u bytes for buffer\n",
> +			level, prefix_str, linebuf_len);
> +		return;
> +	}


-- 
~Randy