From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755178AbaHAQwA (ORCPT ); Fri, 1 Aug 2014 12:52:00 -0400 Received: from top.free-electrons.com ([176.31.233.9]:44885 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751734AbaHAQv7 (ORCPT ); Fri, 1 Aug 2014 12:51:59 -0400 From: Alexandre Belloni To: Nicolas Ferre , Vinod Koul Cc: Dan Williams , Ludovic Desroches , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org, Alexandre Belloni Subject: [PATCHv2] dma: at_hdmac: fix invalid remaining bytes detection Date: Fri, 1 Aug 2014 18:51:46 +0200 Message-Id: <1406911906-397-1-git-send-email-alexandre.belloni@free-electrons.com> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Found using smatch: drivers/dma/at_hdmac.c:299 atc_get_bytes_left() warn: unsigned 'atchan->remain_desc' is never less than zero. Signed-off-by: Alexandre Belloni --- Changes in v2: - remove unnecessary parentheses drivers/dma/at_hdmac.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c index c13a3bb0f594..adb0fbc63f16 100644 --- a/drivers/dma/at_hdmac.c +++ b/drivers/dma/at_hdmac.c @@ -294,14 +294,16 @@ static int atc_get_bytes_left(struct dma_chan *chan) ret = -EINVAL; goto out; } - atchan->remain_desc -= (desc_cur->lli.ctrla & ATC_BTSIZE_MAX) - << (desc_first->tx_width); - if (atchan->remain_desc < 0) { + + count = (desc_cur->lli.ctrla & ATC_BTSIZE_MAX) + << desc_first->tx_width; + if (atchan->remain_desc < count) { ret = -EINVAL; goto out; - } else { - ret = atchan->remain_desc; } + + atchan->remain_desc -= count; + ret = atchan->remain_desc; } else { /* * Get residual bytes when current -- 1.9.1