Re: Variable PTE_FILE_MAX_BITS

[Pete Zaitcev <zaitcev@redhat.com>]

> > would you be so kind to take this and forward to Linus?
> > I think this segment of the code is your brainchild.
> 
> y'know, as I was writing that code I thought "no architecture could be dumb
> enough to make PTE_FILE_MAX_BITS variable".

Two different PTE formats.

> > +	/* This needs to be evaluated at runtime on some platforms */
> > +	if (PTE_FILE_MAX_BITS < BITS_PER_LONG)
> > +		if (pgoff + (size >> PAGE_SHIFT) >= (1UL << PTE_FILE_MAX_BITS))
> > +			return err;
> 
> The reason I didn't do this in the first place is that if PTE_FILE_MAX_BITS
> is 32 (as it is for ia32 PAE), the compiler generates a warning about the
> (1<<32).  I guess it generates a bug, too.
> 
> Ho hum.  I shall make it "1ULL".

Wait, that would be a pessimization. Let me think about it. 

I am thinking that perhaps I can arrange is so that the number
bits on different sparcs would end the same.

-- Pete