From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f175.google.com (mail-pd0-f175.google.com [209.85.192.175]) by kanga.kvack.org (Postfix) with ESMTP id D50C96B0032 for ; Wed, 24 Jun 2015 12:41:02 -0400 (EDT) Received: by pdbep18 with SMTP id ep18so12169823pdb.1 for ; Wed, 24 Jun 2015 09:41:02 -0700 (PDT) Received: from mga02.intel.com (mga02.intel.com. [134.134.136.20]) by mx.google.com with ESMTP id fu16si40719313pdb.173.2015.06.24.09.41.01 for ; Wed, 24 Jun 2015 09:41:01 -0700 (PDT) Date: Wed, 24 Jun 2015 12:40:59 -0400 From: Matthew Wilcox Subject: Re: [PATCH] mm: make GUP handle pfn mapping unless FOLL_GET is requested Message-ID: <20150624164059.GF1971@linux.intel.com> References: <1435141503-100635-1-git-send-email-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1435141503-100635-1-git-send-email-kirill.shutemov@linux.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: "Kirill A. Shutemov" Cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-nvdimm@lists.01.org On Wed, Jun 24, 2015 at 01:25:03PM +0300, Kirill A. Shutemov wrote: > With DAX, pfn mapping becoming more common. The patch adjusts GUP code > to cover pfn mapping for cases when we don't need struct page to > proceed. > > To make it possible, let's change follow_page() code to return -EEXIST > error code if proper page table entry exists, but no corresponding > struct page. __get_user_page() would ignore the error code and move to > the next page frame. > > The immediate effect of the change is working MAP_POPULATE and mlock() > on DAX mappings. > > Signed-off-by: Kirill A. Shutemov > Reviewed-by: Toshi Kani > Cc: Matthew Wilcox Acked-by: Matthew Wilcox -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org