Re: [PATCH v1 1/1] lib/vsprintf: refactor duplicate code to xnumber()

From: Joe Perches
Date: Mon Dec 28 2015 - 13:26:07 EST


On Mon, 2015-12-28 at 20:18 +0200, Andy Shevchenko wrote:
> xnumber() is a special helper to print a fixed size type in a hex format with
> '0x' prefix with padding and reduced size. In the module we have already
> several copies of such code. Consolidate them under xnumber() helper.
>
> There are couple of differences though.
>
> It seems nobody cared about the output in case of CONFIG_KALLSYMS=n when
> printing symbol address because the asked width is not enough to care either
> prefix or last byte. Fixed here.
>
> The %pNF specifier used to be allowed with a specific field width, though there
> is neither any user of it nor mention in the documentation.
>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> ---
>  lib/vsprintf.c | 43 +++++++++++++++----------------------------
>  1 file changed, 15 insertions(+), 28 deletions(-)
>
> diff --git a/lib/vsprintf.c b/lib/vsprintf.c
> index dcf5646..e971549 100644
> --- a/lib/vsprintf.c
> +++ b/lib/vsprintf.c
> @@ -514,6 +514,16 @@ char *number(char *buf, char *end, unsigned long long num,
>   return buf;
>  }
>  
> +static noinline_for_stack
> +char *xnumber(char *buf, char *end, unsigned long long value, unsigned int type,
> +       struct printf_spec spec)

xnumber isn't a great name.

unsigned int type should probably be size_t size

> +{
> + spec.field_width = 2 + 2 * type;
> + spec.flags |= SPECIAL | SMALL | ZEROPAD;
> + spec.base = 16;
> + return number(buf, end, value, spec);
> +}
> +
>  static void move_right(char *buf, char *end, unsigned len, unsigned spaces)
>  {
>   size_t size;
> @@ -649,11 +659,7 @@ char *symbol_string(char *buf, char *end, void *ptr,
>  
>   return string(buf, end, sym, spec);
>  #else
> - spec.field_width = 2 * sizeof(void *);
> - spec.flags |= SPECIAL | SMALL | ZEROPAD;
> - spec.base = 16;
> -
> - return number(buf, end, value, spec);
> + return xnumber(buf, end, value, sizeof(void *), spec);

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