From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752043AbeBEVAT (ORCPT ); Mon, 5 Feb 2018 16:00:19 -0500 Received: from gateway21.websitewelcome.com ([192.185.45.31]:47809 "EHLO gateway21.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751923AbeBEVAM (ORCPT ); Mon, 5 Feb 2018 16:00:12 -0500 Date: Mon, 5 Feb 2018 14:36:49 -0600 From: "Gustavo A. R. Silva" To: Hans Verkuil , Mauro Carvalho Chehab Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH v2 8/8] platform: vivid-cec: use 64-bit arithmetic instead of 32-bit Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - gator4166.hostgator.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - embeddedor.com X-BWhitelist: no X-Source-IP: 189.152.201.65 X-Source-L: No X-Exim-ID: 1einVS-003iAl-2u X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedgus) [189.152.201.65]:48142 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 41 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add suffix ULL to constant 10 in order to give the compiler complete information about the proper arithmetic to use. Notice that this constant is used in a context that expects an expression of type u64 (64 bits, unsigned). The expression len * 10 * CEC_TIM_DATA_BIT_TOTAL is currently being evaluated using 32-bit arithmetic. Also, remove unnecessary parentheses and add a code comment to make it clear what is the reason of the code change. Addresses-Coverity-ID: 1454996 Signed-off-by: Gustavo A. R. Silva --- Changes in v2: - Update subject and changelog to better reflect the proposed code changes. - Add suffix ULL to constant instead of casting a variable. - Remove unncessary parentheses. - Add code comment. drivers/media/platform/vivid/vivid-cec.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/media/platform/vivid/vivid-cec.c b/drivers/media/platform/vivid/vivid-cec.c index b55d278..614787b 100644 --- a/drivers/media/platform/vivid/vivid-cec.c +++ b/drivers/media/platform/vivid/vivid-cec.c @@ -82,8 +82,15 @@ static void vivid_cec_pin_adap_events(struct cec_adapter *adap, ktime_t ts, if (adap == NULL) return; - ts = ktime_sub_us(ts, (CEC_TIM_START_BIT_TOTAL + - len * 10 * CEC_TIM_DATA_BIT_TOTAL)); + + /* + * Suffix ULL on constant 10 makes the expression + * CEC_TIM_START_BIT_TOTAL + 10ULL * len * CEC_TIM_DATA_BIT_TOTAL + * be evaluated using 64-bit unsigned arithmetic (u64), which + * is what ktime_sub_us expects as second argument. + */ + ts = ktime_sub_us(ts, CEC_TIM_START_BIT_TOTAL + + 10ULL * len * CEC_TIM_DATA_BIT_TOTAL); cec_queue_pin_cec_event(adap, false, ts); ts = ktime_add_us(ts, CEC_TIM_START_BIT_LOW); cec_queue_pin_cec_event(adap, true, ts); -- 2.7.4