Re: [PATCH] mwifiex: Using %*phD instead of print_hex_dump_bytes

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Thu, 2012-10-04 at 09:32 -0700, Joe Perches wrote: 
> On Thu, 2012-10-04 at 12:16 +0300, Andrei Emeltchenko wrote:
> > From: Andrei Emeltchenko <andrei.emeltchenko@intel.com>
> > 
> > Make output more readable and remove unneeded function call.
> > 
> > ...
> > mwifiex_sdio mmc0:0001:1: last_cmd_index = 3
> > last_cmd_id: 00000000: 28 00 28 00 28                            (.(.(
> > ...
> > 
> > would be changed to:
> > 
> > ...
> > mwifiex_sdio mmc0:0001:1: last_cmd_index = 3
> > mwifiex_sdio mmc0:0001:1: last_cmd_id: 28 00 28 00 28
> > ...
> 
> (added Andy Shevchenko)
> 
> Hi Andrei.  That's probably a better output style too
> as the ascii isn't likely useful.
> 
> One non-nit as a style issue for Andy Shevchenko:
> 
> > diff --git a/drivers/net/wireless/mwifiex/cmdevt.c b/drivers/net/wireless/mwifiex/cmdevt.c
> []
> > @@ -917,21 +917,20 @@ mwifiex_cmd_timeout_func(unsigned long function_context)
> []
> > +		dev_err(adapter->dev, "last_cmd_id: %*ph\n", DBG_CMD_NUM,
> > +			adapter->dbg.last_cmd_id);
> > +		dev_err(adapter->dev, "last_cmd_act: %*ph\n", DBG_CMD_NUM,
> > +			adapter->dbg.last_cmd_act);
> 
> When the number of bytes is fixed, it might be nicer
> to use a format like "%<num>ph" so that the function
> argument stack doesn't have the width pushed but it's
> fixed in the format.
> 
> This case would definitely not work well though as it's
> a #define rather than a simple number and I think
> using "%" stringize(some_define) "ph" is not nice.
> 
> Maybe this case argues more for always using "%*ph".
> At least that's easily greppable.
> 
> Andy?
First of all, the current linux-next has at least two definitions of
that constant:
drivers/net/wireless/mwifiex/ioctl.h:175:#define DBG_CMD_NUM    5
drivers/net/wireless/mwifiex/main.h:118:#define DBG_CMD_NUM 5

I checked briefly the code and found that the constant is heavily used
as a definition for the length of static byte arrays. So, in that case
probably better to use %*ph, but apply sizeof(cool_var) instead of
putting constant there.


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