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

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Message-ID: <CAHp75VdfwmGiHzyCtQ_xgHb0zDSvS-+rGKnHwuHA-s4dPc-OXg@mail.gmail.com>
Date:	Tue, 29 Dec 2015 00:29:00 +0200
From:	Andy Shevchenko <andy.shevchenko@...il.com>
To:	Rasmus Villemoes <linux@...musvillemoes.dk>
Cc:	Joe Perches <joe@...ches.com>,
	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1 1/1] lib/vsprintf: refactor duplicate code to xnumber()

On Tue, Dec 29, 2015 at 12:20 AM, Rasmus Villemoes
<linux@...musvillemoes.dk> wrote:
> On Mon, Dec 28 2015, Rasmus Villemoes <linux@...musvillemoes.dk> wrote:
>
>>
>> Is there any aspect of the passed-through printf_spec which isn't
>> overridden in xnumber? The users are/will be various %p extensions,
>> which probably means that no-one passes a non-default precision (gcc
>> complains about %.*p), and the remaining possible flags (PLUS, LEFT,
>> SPACE) are useless and/or impossible to pass to %p
>
> Actually, LEFT can be passed to %p (or get set by passing a negative
> field width via %*p), which would be actively harmful: When LEFT is set,
> number() explicitly removes the ZEROPAD flag, so we'd get "0xabcdef  "
> instead of "0x00abcdef".

My opinion we have to establish strict rules what we print in case of
prefixed pointer (when #ifdef is false in some cases, e.g. struct clk)
or fixed type values, such as phys_addr_t. I mean to always have a
maximum width for the type on the running architecture.

-- 
With Best Regards,
Andy Shevchenko
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