Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933267AbcJUNPK (ORCPT ); Fri, 21 Oct 2016 09:15:10 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:44085 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755476AbcJUNPJ (ORCPT ); Fri, 21 Oct 2016 09:15:09 -0400 Date: Fri, 21 Oct 2016 06:15:05 -0700 From: Christoph Hellwig To: Richard Weinberger Cc: Christoph Hellwig , Naga Sureshkumar Relli , "dwmw2@infradead.org" , "computersforpeace@gmail.com" , "dedekind1@gmail.com" , "adrian.hunter@intel.com" , "michal.simek@xilinx.com" , Punnaiah Choudary Kalluri , "linux-mtd@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Boris Brezillon Subject: Re: UBIFS with dma on 4.6 kernel is not working Message-ID: <20161021131505.GA25942@infradead.org> References: <519a83bf-1244-5151-b873-bb8e1f2db3c6@nod.at> <20161021125313.GA16754@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.6.1 (2016-04-27) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 658 Lines: 13 On Fri, Oct 21, 2016 at 03:07:57PM +0200, Richard Weinberger wrote: > Hmm, thought this is still problematic on VIVT architectures. > Boris tried to provide a solution for that some time ago: > http://www.spinics.net/lists/arm-kernel/msg494025.html Things have been working fine for approx 10 years when using flush_kernel_vmap_range before doing I/O using the physical addresses and then invalidate_kernel_vmap_range when completing the I/O and going back to using the virtual mapping for XFS. Of course all this assumes at least the higher level that did the vm_map_ram operation knows about this dance between virtually mapped and physiscal addresses.