Messages in this thread Patch in this message | | | Date | Thu, 22 May 2014 08:26:39 +0800 (CST) | From | 管雪涛 <> | Subject | 回复: [PATCH linux-next] net/dccp/timer.c: use 'u 64' instead of 's64' to avoid compiler's warning |
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----- Chen Gang <gang.chen.5i5j@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.5i5j@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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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