Re: [PATCH] uio: Support 36-bit physical addresses on 32-bit systems

[Hans J. Koch]

On Fri, Oct 14, 2011 at 12:36:33PM -0600, Greg KH wrote:
> On Fri, Oct 14, 2011 at 08:31:45PM +0200, Hans J. Koch wrote:
> > On Thu, Oct 13, 2011 at 10:50:58AM -0500, Kumar Gala wrote:
> > > From: Kai Jiang <Kai.Jiang@xxxxxxxxxxxxx>
> > > 
> > > To support >32-bit physical addresses for UIO_MEM_PHYS type we need to
> > > extend the width of 'addr' in struct uio_mem.  Numerous platforms like
> > > embedded PPC, ARM, and X86 have support for systems with larger physical
> > > address than logical.
> > > 
> > > Since 'addr' may contain a physical, logical, or virtual address the
> > > easiest solution is to just change the type to 'phys_addr_t' which
> > > should always be greater than or equal to the sizeof(void *) such that
> > > it can properly hold any of the address types.
> > > 
> > > For physical address we can support up to a 44-bit physical address on a
> > > typical 32-bit system as we utilize remap_pfn_range() for the mapping of
> > > the memory region and pfn's are represnted by shifting the address by
> > > the page size (typically 4k).
> > > 
> > > Signed-off-by: Kai Jiang <Kai.Jiang@xxxxxxxxxxxxx>
> > > Signed-off-by: Minghuan Lian <Minghuan.Lian@xxxxxxxxxxxxx>
> > > Signed-off-by: Kumar Gala <galak@xxxxxxxxxxxxxxxxxxx>
> > 
> > Signed-off-by: "Hans J. Koch" <hjk@xxxxxxxxxxxx>
> > 
> > That looks good to me. There's an unnecessary cast (see below), but I fixed that
> > on the way.
> > 
> > Greg, please pull this from branch uio-for-gregkh from
> > 
> > git://hansjkoch.de/git/linux-hjk
> 
> Care to send it as an email?  I can apply it easier that way as I have
> limited internet access while on the road.
> 
> greg k-h