On 2013/12/2 22:51, Vlad Yasevich wrote:
> On 12/02/2013 07:03 AM, Wang Weidong wrote:
>> On 2013/12/2 19:56, Neil Horman wrote:
>>> On Mon, Dec 02, 2013 at 02:51:45PM +0800, Wang Weidong wrote:
>>>> From: Wang Weidong <wangweidong1@xxxxxxxxxx>
>>>>
>>>> when I setted the max_burst to 0, do the lksctp-tools I got hang.
>>>> I found sctp_transport_burst_limited would make the cwnd to 0.
>>>> so I make the max_burst min value to 1.
>>>> Signed-off-by: Wang Weidong <wangweidong1@xxxxxxxxxx>
>>>> ---
>>>> net/sctp/sysctl.c | 2 +-
>>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c
>>>> index 7637e8e..46832d3 100644
>>>> --- a/net/sctp/sysctl.c
>>>> +++ b/net/sctp/sysctl.c
>>>> @@ -135,7 +135,7 @@ static struct ctl_table sctp_net_table[] = {
>>>> .maxlen = sizeof(int),
>>>> .mode = 0644,
>>>> .proc_handler = proc_dointvec_minmax,
>>>> - .extra1 = &zero,
>>>> + .extra1 = &one,
>>>> .extra2 = &int_max
>>>> },
>>>> {
>>>> --
>>>> 1.7.12
>>>>
>>>>
>>>
>>>
>>> This seems like a band-aid to me. There are a few things wrong:
>>>
>>> 1) You can also set the the max_burst via setsockopt, and so this would need to
>>> be checked in that path as well.
>>>
>>> 2) I don't see how having a cwnd of zero would cause a hang. It looks like a
>>> cwnd of zero would perpetually place the association in a slow start state,
>>> which is silly but not illegal.
>>>
>>
>> Hm, Good suggestions. Ok, I will try it again and find the root cause.
>> Thanks!
>
> It's really simple. sctp_transport_burst_limited() should simply do
> nothing if max_burst is 0, essentially allowing unlimited bursts.
>
> -vlad
>
I will add the a check of max_burst, if max_burst is 0, just do nothing. Michael
point out that it just disable max_burst which declared in rfc6458#section-8.1.24
as well.
Thanks.
>>
>>> Please investigate the acutally root cause of the problem before just avoiding
>>> it like this.
>>>
>>> Thanks!
>>> Neil
>>>
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>>
>>
>
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