Re: PATCH: Bogus disk geometry on large disks

[Matthew Wilcox <matthew@wil.cx>]

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On Fri, May 26, 2006 at 07:22:18PM +0100, Alan Cox wrote:
> On Gwe, 2006-05-26 at 11:57 -0600, Matthew Wilcox wrote:
> > On Fri, May 26, 2006 at 05:29:25PM +0100, Alan Cox wrote:
> > >  
> > > -	if (ret == -1) {
> > > +	if (ret == -1 && capacity < (1ULL << 32)) {
> > >  		/* pick some standard mapping with at most 1024 cylinders,
> > 
> > won't that provoke a gcc warning when sector_t is 32-bit?  how about ...
> 
> I don't believe it will as the type is forced to "1ULL"

gcc disagrees with you ;-)

$ cat test.c 
unsigned int y;

int main(void)
{
        if (y < (1ULL << 32))
                return 0;
        return 1;
}
$ gcc -O2 -W -Wall -o test test.c
test.c: In function ‘main’:
test.c:5: warning: comparison is always true due to limited range of data type

$ cat test.c 
unsigned int y;

int main(void)
{
        if (((y >> 16) >> 16) > 0)
                return 0;
        return 1;
}
$ gcc -O2 -W -Wall -o test test.c

(anyone know how you turn off that fucking UTF8 crap that gcc insists
on putting into its warning/error messages?  Who thought that was a
good idea?)

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