Commit fc49d3d7 authored by Gustavo A. R. Silva's avatar Gustavo A. R. Silva Committed by Mauro Carvalho Chehab

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: default avatarGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: default avatarHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@s-opensource.com>
parent eb64311f
...@@ -70,8 +70,15 @@ static void vivid_cec_pin_adap_events(struct cec_adapter *adap, ktime_t ts, ...@@ -70,8 +70,15 @@ static void vivid_cec_pin_adap_events(struct cec_adapter *adap, ktime_t ts,
if (adap == NULL) if (adap == NULL)
return; 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); cec_queue_pin_cec_event(adap, false, ts);
ts = ktime_add_us(ts, CEC_TIM_START_BIT_LOW); ts = ktime_add_us(ts, CEC_TIM_START_BIT_LOW);
cec_queue_pin_cec_event(adap, true, ts); cec_queue_pin_cec_event(adap, true, ts);
......
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