From fc49d3d7dc26a43f8d3b1874c7ddb975a49e8a8c Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Tue, 6 Feb 2018 11:53:44 -0500 Subject: [PATCH] media: platform: vivid-cec: use 64-bit arithmetic instead of 32-bit 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 ("Unintentional integer overflow") Signed-off-by: Gustavo A. R. Silva Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- 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 619bd8435b7f..c2c889d6dcf5 100644 --- a/drivers/media/platform/vivid/vivid-cec.c +++ b/drivers/media/platform/vivid/vivid-cec.c @@ -70,8 +70,15 @@ 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 + * to 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); -- 2.30.2