From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752879Ab1JQSft (ORCPT ); Mon, 17 Oct 2011 14:35:49 -0400 Received: from cantor2.suse.de ([195.135.220.15]:44311 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751542Ab1JQSfs (ORCPT ); Mon, 17 Oct 2011 14:35:48 -0400 Date: Mon, 17 Oct 2011 11:23:45 -0700 From: Greg KH To: "Hans J. Koch" Cc: Kumar Gala , linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org, Kai Jiang Subject: Re: [PATCH] uio: Support 36-bit physical addresses on 32-bit systems Message-ID: <20111017182345.GA14416@suse.de> References: <1318521058-15662-1-git-send-email-galak@kernel.crashing.org> <20111014183144.GD28556@local> <4D73F261-3795-4F71-9921-568C1B9F06E0@kernel.crashing.org> <20111017171859.GB13919@local> <20111017180350.GC13919@local> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20111017180350.GC13919@local> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 17, 2011 at 08:03:51PM +0200, Hans J. Koch wrote: > On Mon, Oct 17, 2011 at 07:18:59PM +0200, Hans J. Koch wrote: > > On Mon, Oct 17, 2011 at 11:00:55AM -0500, Kumar Gala wrote: > > > > > > On Oct 14, 2011, at 1:31 PM, Hans J. Koch wrote: > > > > > > > On Thu, Oct 13, 2011 at 10:50:58AM -0500, Kumar Gala wrote: > > > >> From: Kai Jiang > > > >> > > > >> 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 > > > >> Signed-off-by: Minghuan Lian > > > >> Signed-off-by: Kumar Gala > > > > > > > > Signed-off-by: "Hans J. Koch" > > > > > > > > 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 > > > > > > > > Thanks, > > > > Hans > > > > > > I think removing that cast is wrong: > > > > > > drivers/uio/uio.c: In function 'uio_vma_fault': > > > drivers/uio/uio.c:637:26: warning: cast to pointer from integer of different size > > > > Hmm, on what platform did you see this? I tested on 32bit-x86 and didn't get > > any warnings. > > OK, you're right. I turned on CONFIG_HIGHMEM64G and got that warning. Damned x86... > > Greg, can you fix it, or should I send the patch again? Please send it again.