From: Stuart Swales <stuart.swales.croftnuisk@gmail.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>,
Russell King <rmk+kernel@arm.linux.org.uk>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] adfs: add hexadecimal filetype suffix option
Date: Wed, 23 Mar 2011 23:08:43 +0000 [thread overview]
Message-ID: <4D8A7D7B.1080001@gmail.com> (raw)
In-Reply-To: <20110323135835.0c2e296c.akpm@linux-foundation.org>
The file typing code is using -1 (truncated to __u16) to represent the
case when no explicit 12-bit file type was set on the file, such as is
the case where the file has explicit 32-bit load and execute addresses
(Acorn specific legacy stuff, started with the BBC Micro). It would
seem to be best if the -1 were replaced by 0xffffu.
Stuart
On 23/03/2011 20:58, Andrew Morton wrote:
> On Wed, 23 Mar 2011 21:36:48 +0100
> Geert Uytterhoeven<geert@linux-m68k.org> wrote:
>
>> On Thu, Jan 20, 2011 at 00:49, Andrew Morton<akpm@linux-foundation.org> wrote:
>>> On Wed, 12 Jan 2011 18:07:23 +0000
>>> Stuart Swales<stuart.swales.croftnuisk@gmail.com> wrote:
>>>> From: Stuart Swales<stuart.swales.croftnuisk@gmail.com>
>>
>>>> +static inline int append_filetype_suffix(char *buf, __u16 filetype)
>>>> +{
>>>> + __ __ if ((__u16) -1 == filetype)
>>>
>>> unneeded cast.
>>
>> My compiler tends to disagree. On current mainline, it says:
>>
>> fs/adfs/adfs.h: In function ___append_filetype_suffix___:
>> fs/adfs/adfs.h:115: warning: comparison is always false due to limited
>> range of data type
>>
>
> hm, OK, I'll add a cast.
>
> The code seems a bit fishy - it wants 0xffff but the comment says it's
> handling a 12-bit quantity. Obviously the all-ones pattern has some
> magical out-of-band meaning here, but it is not explained what that
> meaning *is*. Perhaps that is described elsewhere.
>
--
Stuart Swales
prev parent reply other threads:[~2011-03-23 23:06 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <4D2DEDDB.1070605@gmail.com>
2011-01-19 23:49 ` [PATCH] adfs: add hexadecimal filetype suffix option Andrew Morton
2011-01-21 14:34 ` Stuart Swales
2011-01-21 16:47 ` Arnd Bergmann
2011-01-21 17:26 ` Russell King
2011-01-21 22:02 ` Arnd Bergmann
2011-01-22 0:57 ` Stuart Swales
2011-01-21 14:43 ` Stuart Swales
2011-01-21 18:26 ` Andrew Morton
2011-03-23 20:36 ` Geert Uytterhoeven
2011-03-23 20:56 ` Al Viro
2011-03-23 20:58 ` Andrew Morton
2011-03-23 23:08 ` Stuart Swales [this message]
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