From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933471AbcKVR1M (ORCPT ); Tue, 22 Nov 2016 12:27:12 -0500 Received: from mezzanine.sirena.org.uk ([106.187.55.193]:41486 "EHLO mezzanine.sirena.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933363AbcKVR1G (ORCPT ); Tue, 22 Nov 2016 12:27:06 -0500 From: Mark Brown To: Juan Gutierrez Cc: Mark Brown , broonie@kernel.org, linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org, juan.gutierrez@nxp.com, yibin.gong@nxp.com, fabio.estevam@nxp.com In-Reply-To: <1479768603-15583-1-git-send-email-juan.gutierrez@nxp.com> Message-Id: Date: Tue, 22 Nov 2016 17:26:58 +0000 X-SA-Exim-Connect-IP: 2001:470:1f1d:6b5::3 X-SA-Exim-Mail-From: broonie@sirena.org.uk Subject: Applied "spi: use sg_next for walking through the allocated scatterlist table" to the spi tree X-SA-Exim-Version: 4.2.1 (built Mon, 26 Dec 2011 16:24:06 +0000) X-SA-Exim-Scanned: No (on mezzanine.sirena.org.uk); Unknown failure Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The patch spi: use sg_next for walking through the allocated scatterlist table has been applied to the spi tree at git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted. You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed. If any updates are required or you are submitting further changes they should be sent as incremental updates against current git, existing patches will not be replaced. Please add any relevant lists and maintainers to the CCs when replying to this mail. Thanks, Mark >>From 8dd4a0163e7315d196e54780591b7426fa78e1fa Mon Sep 17 00:00:00 2001 From: Juan Gutierrez Date: Mon, 21 Nov 2016 16:50:03 -0600 Subject: [PATCH] spi: use sg_next for walking through the allocated scatterlist table A null dereference or Oops exception might occurs when reading at once the whole content of an spi-nor of big enough size that requires an scatterlist table that does not fit into one single page. The spi_map_buf function is ignoring the chained sg case by dereferenceing the scatterlist elements in an array fashion. This wrongly assumes that the allocation of the scatterlist elements are contiguous. This is true as long as the scatterlist table fits within a PAGE_SIZE. However, for allocation where the scatter table is bigger than that, the pages allocated by sg_alloc might not be contigous. The sg table can be properly walked by sg_next instead of using an array. Signed-off-by: Juan Gutierrez Signed-off-by: Mark Brown --- drivers/spi/spi.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 5787b723b593..2cfe67f73476 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -720,6 +720,7 @@ static int spi_map_buf(struct spi_master *master, struct device *dev, int desc_len; int sgs; struct page *vm_page; + struct scatterlist *sg; void *sg_buf; size_t min; int i, ret; @@ -738,6 +739,7 @@ static int spi_map_buf(struct spi_master *master, struct device *dev, if (ret != 0) return ret; + sg = &sgt->sgl[0]; for (i = 0; i < sgs; i++) { if (vmalloced_buf || kmap_buf) { @@ -751,16 +753,17 @@ static int spi_map_buf(struct spi_master *master, struct device *dev, sg_free_table(sgt); return -ENOMEM; } - sg_set_page(&sgt->sgl[i], vm_page, + sg_set_page(sg, vm_page, min, offset_in_page(buf)); } else { min = min_t(size_t, len, desc_len); sg_buf = buf; - sg_set_buf(&sgt->sgl[i], sg_buf, min); + sg_set_buf(sg, sg_buf, min); } buf += min; len -= min; + sg = sg_next(sg); } ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir); -- 2.10.2