Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753291AbdFLP35 (ORCPT ); Mon, 12 Jun 2017 11:29:57 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:40050 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752797AbdFLP3v (ORCPT ); Mon, 12 Jun 2017 11:29:51 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Thomas Petazzoni , Vinod Koul Subject: [PATCH 4.11 060/150] dmaengine: mv_xor_v2: properly handle wrapping in the array of HW descriptors Date: Mon, 12 Jun 2017 17:24:27 +0200 Message-Id: <20170612152522.005700626@linuxfoundation.org> X-Mailer: git-send-email 2.13.1 In-Reply-To: <20170612152519.404936272@linuxfoundation.org> References: <20170612152519.404936272@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2376 Lines: 68 4.11-stable review patch. If anyone has any objections, please let me know. ------------------ From: Thomas Petazzoni commit 2aab4e18152cd30cb5d2f4c27629fc8a04aed979 upstream. mv_xor_v2_tasklet() is looping over completed HW descriptors. Before the loop, it initializes 'next_pending_hw_desc' to the first HW descriptor to handle, and then the loop simply increments this point, without taking care of wrapping when we reach the last HW descriptor. The 'pending_ptr' index was being wrapped back to 0 at the end, but it wasn't used in each iteration of the loop to calculate next_pending_hw_desc. This commit fixes that, and makes next_pending_hw_desc a variable local to the loop itself. Fixes: 19a340b1a820 ("dmaengine: mv_xor_v2: new driver") Signed-off-by: Thomas Petazzoni Signed-off-by: Vinod Koul Signed-off-by: Greg Kroah-Hartman --- drivers/dma/mv_xor_v2.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) --- a/drivers/dma/mv_xor_v2.c +++ b/drivers/dma/mv_xor_v2.c @@ -560,7 +560,6 @@ static void mv_xor_v2_tasklet(unsigned l { struct mv_xor_v2_device *xor_dev = (struct mv_xor_v2_device *) data; int pending_ptr, num_of_pending, i; - struct mv_xor_v2_descriptor *next_pending_hw_desc = NULL; struct mv_xor_v2_sw_desc *next_pending_sw_desc = NULL; dev_dbg(xor_dev->dmadev.dev, "%s %d\n", __func__, __LINE__); @@ -568,17 +567,10 @@ static void mv_xor_v2_tasklet(unsigned l /* get the pending descriptors parameters */ num_of_pending = mv_xor_v2_get_pending_params(xor_dev, &pending_ptr); - /* next HW descriptor */ - next_pending_hw_desc = xor_dev->hw_desq_virt + pending_ptr; - /* loop over free descriptors */ for (i = 0; i < num_of_pending; i++) { - - if (pending_ptr > MV_XOR_V2_DESC_NUM) - pending_ptr = 0; - - if (next_pending_sw_desc != NULL) - next_pending_hw_desc++; + struct mv_xor_v2_descriptor *next_pending_hw_desc = + xor_dev->hw_desq_virt + pending_ptr; /* get the SW descriptor related to the HW descriptor */ next_pending_sw_desc = @@ -614,6 +606,8 @@ static void mv_xor_v2_tasklet(unsigned l /* increment the next descriptor */ pending_ptr++; + if (pending_ptr >= MV_XOR_V2_DESC_NUM) + pending_ptr = 0; } if (num_of_pending != 0) {