From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 97525C6778F for ; Thu, 26 Jul 2018 15:09:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5AEE32064D for ; Thu, 26 Jul 2018 15:09:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5AEE32064D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731632AbeGZQ1C (ORCPT ); Thu, 26 Jul 2018 12:27:02 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:56148 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730083AbeGZQ1C (ORCPT ); Thu, 26 Jul 2018 12:27:02 -0400 Received: from localhost (unknown [62.119.166.9]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 3ACE4CFE; Thu, 26 Jul 2018 15:09:43 +0000 (UTC) Date: Thu, 26 Jul 2018 17:09:40 +0200 From: Greg Kroah-Hartman To: Ben Hutchings Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Maxime Chevallier , Mark Brown , Sudip Mukherjee Subject: Re: [PATCH 4.4 101/105] spi: Fix scatterlist elements size in spi_map_buf Message-ID: <20180726150940.GD27305@kroah.com> References: <20180701153149.382300170@linuxfoundation.org> <20180701153156.693937436@linuxfoundation.org> <1532114624.21552.43.camel@codethink.co.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1532114624.21552.43.camel@codethink.co.uk> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 20, 2018 at 08:23:44PM +0100, Ben Hutchings wrote: > On Sun, 2018-07-01 at 18:02 +0200, Greg Kroah-Hartman wrote: > > 4.4-stable review patch.  If anyone has any objections, please let me know. > > > > ------------------ > > > > From: Maxime Chevallier > > > > commit ce99319a182fe766be67f96338386f3ec73e321c upstream. > > > > When SPI transfers can be offloaded using DMA, the SPI core need to > > build a scatterlist to make sure that the buffer to be transferred is > > dma-able. > > > > This patch fixes the scatterlist entry size computation in the case > > where the maximum acceptable scatterlist entry supported by the DMA > > controller is less than PAGE_SIZE, when the buffer is vmalloced. > > > > For each entry, the actual size is given by the minimum between the > > desc_len (which is the max buffer size supported by the DMA controller) > > and the remaining buffer length until we cross a page boundary. > > > > Fixes: 65598c13fd66 ("spi: Fix per-page mapping of unaligned vmalloc-ed buffer") > > Signed-off-by: Maxime Chevallier > > Signed-off-by: Mark Brown > > Cc: stable@vger.kernel.org > > Signed-off-by: Sudip Mukherjee > > Signed-off-by: Greg Kroah-Hartman > > --- > >  drivers/spi/spi.c |   10 ++++++++-- > >  1 file changed, 8 insertions(+), 2 deletions(-) > > > > --- a/drivers/spi/spi.c > > +++ b/drivers/spi/spi.c > > @@ -707,8 +707,14 @@ static int spi_map_buf(struct spi_master > >   for (i = 0; i < sgs; i++) { > >   > >   if (vmalloced_buf) { > > - min = min_t(size_t, > > -     len, desc_len - offset_in_page(buf)); > > + /* > > +  * Next scatterlist entry size is the minimum between > > +  * the desc_len and the remaining buffer length that > > +  * fits in a page. > > +  */ > > + min = min_t(size_t, desc_len, > > +     min_t(size_t, len, > > +   PAGE_SIZE - offset_in_page(buf))); > >   vm_page = vmalloc_to_page(buf); > >   if (!vm_page) { > >   sg_free_table(sgt); > > I think this makes sense upstream, but in 4.4 it seems to be a no-op > since desc_len is always set to PAGE_SIZE when vmalloced_buf is true. > This fix depends on (at least) commit df88e91bbfd1 "spi: respect the > maximum segment size of DMA device" which went into 4.6. Good catch. I'll leave it as-is for now though. thanks, greg k-h