From mboxrd@z Thu Jan 1 00:00:00 1970 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: List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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.