Re: [PATCH v2 net-next] net: poll/select low latency socket support

From: Eric Dumazet
Date: Tue Jun 18 2013 - 05:08:43 EST


On Tue, 2013-06-18 at 11:58 +0300, Eliezer Tamir wrote:
> select/poll busy-poll support.
>


> */
> -static inline u64 ll_end_time(struct sock *sk)
> +static inline u64 ll_sk_end_time(struct sock *sk)
> {
> - u64 end_time = ACCESS_ONCE(sk->sk_ll_usec);
> -
> - /* we don't mind a ~2.5% imprecision
> - * sk->sk_ll_usec is a u_int so this can't overflow
> - */
> - end_time = (end_time << 10) + sched_clock();
> + return (ACCESS_ONCE(sk->sk_ll_usec) << 10) + sched_clock();
> +}
>

This is the fourth time you try to introduce an overflow in this code.

(same for ll_end_time())




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