----- Chen Gang <gang.chen.5...@gmail.com> 写道：
> 'dccp_timestamp_seed' is initialized once by ktime_get_real() in
> dccp_timestamping_init(). It is always less than ktime_get_real()
> in dccp_timestamp().
>
> Then, ktime_us_delta() in dccp_timestamp() will always return positive
> number. So can use manual type cast to let compiler and do_div() know
> about it to avoid warning.
>
> The related warning (with allmodconfig under unicore32):
>
> CC [M] net/dccp/timer.o
> net/dccp/timer.c: In function ‘dccp_timestamp’:
> net/dccp/timer.c:285: warning: comparison of distinct pointer types lacks a
> cast
>
>
> Signed-off-by: Chen Gang <gang.chen.5...@gmail.com>
> ---
> net/dccp/timer.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/dccp/timer.c b/net/dccp/timer.c
> index 16f0b22..1cd46a3 100644
> --- a/net/dccp/timer.c
> +++ b/net/dccp/timer.c
> @@ -280,7 +280,7 @@ static ktime_t dccp_timestamp_seed;
> */
> u32 dccp_timestamp(void)
> {
> - s64 delta = ktime_us_delta(ktime_get_real(), dccp_timestamp_seed);
> + u64 delta = (u64)ktime_us_delta(ktime_get_real(), dccp_timestamp_seed);
Do you assume that delta should be very small?
Otherwise, return value will be different if data type is changed.
>
> do_div(delta, 10);
> return delta;
> --
> 1.9.2.459.g68773ac
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