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

From: Eliezer Tamir <[email-masked]>
Date: Tue, 18 Jun 2013 12:12:24 +0300

On 18/06/2013 12:08, Eric Dumazet wrote:
> 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())

sorry,
Please review the rest of the patch to see if you have any other comments.