linux-kernel - Re: [RFC][PATCH 1/2] lib: printf: append support of '%*p[Mm][FR]'

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Date:	Fri, 29 Jun 2012 09:08:06 -0700
From:	Joe Perches <joe@...ches.com>
To:	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:	proski@....org, Andrei Emeltchenko <andrei.emeltchenko@...el.com>,
	linux-wireless@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC][PATCH 1/2] lib: printf: append support of '%*p[Mm][FR]'

On Fri, 2012-06-29 at 18:58 +0300, Andy Shevchenko wrote:
> There are many places in the kernel where the drivers print small buffers as a
> hex string. This patch adds a support of the variable width buffer to print it
> as a hex string with a delimiter. The idea came from Pavel Roskin here:
> http://www.digipedia.pl/usenet/thread/18835/17449/

Seems sensible, but one stack caveat below

> diff --git a/lib/vsprintf.c b/lib/vsprintf.c
[]
> @@ -655,11 +655,12 @@ char *resource_string(char *buf, char *end, struct resource *res,
>  }
>  
>  static noinline_for_stack
> -char *mac_address_string(char *buf, char *end, u8 *addr,
> -			 struct printf_spec spec, const char *fmt)
> +char *hex_string(char *buf, char *end, u8 *addr, struct printf_spec spec,
> +		 const char *fmt)
>  {
> -	char mac_addr[sizeof("xx:xx:xx:xx:xx:xx")];
> -	char *p = mac_addr;
> +	char hex_str[64*3];	/* support up to 64 bytes to print */

Might be too much stack though.


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