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Date: Wed, 23 Mar 2011 20:56:37 +0000
From: Al Viro <viro@ZenIV.linux.org.uk>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
        Stuart Swales <stuart.swales.croftnuisk@gmail.com>,
        Russell King <rmk+kernel@arm.linux.org.uk>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] adfs: add hexadecimal filetype suffix option
Message-ID: <20110323205637.GB22723@ZenIV.linux.org.uk>
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On Wed, Mar 23, 2011 at 09:36:48PM +0100, Geert Uytterhoeven 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

And it's absolutely right - unsigned short it promoted to int as part of
usual arithmetic conversions and the value is not changed.  And it's *not*
going to be equal to -1.