Subject: Re: [PATCH net-next 2/5] net_sched: add replace func in struct Qdisc_ops

From: Yang Yingliang <[email-masked]>
Date: Fri, 7 Mar 2014 10:13:31 +0800

On 2014/3/6 22:55, Eric Dumazet wrote:
> On Thu, 2014-03-06 at 21:08 +0800, Yang Yingliang wrote:
>> Add replace func, if NLM_F_REPLACE is set, use replace func.
>> Otherwise, use change func.
>>
>> Signed-off-by: Yang Yingliang <[email-masked]>
>> ---
>>  include/net/sch_generic.h |  1 +
>>  net/sched/sch_api.c       | 12 +++++++++---
>>  2 files changed, 10 insertions(+), 3 deletions(-)
>>
>> diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
>> index d062f81c692f..ef8a41bcb9a7 100644
>> --- a/include/net/sch_generic.h
>> +++ b/include/net/sch_generic.h
>> @@ -170,6 +170,7 @@ struct Qdisc_ops {
>>  	void			(*reset)(struct Qdisc *);
>>  	void			(*destroy)(struct Qdisc *);
>>  	int			(*change)(struct Qdisc *, struct nlattr *arg);
>> +	int			(*replace)(struct Qdisc *, struct nlattr *arg);
>>  	void			(*attach)(struct Qdisc *);
>>  
>>  	int			(*dump)(struct Qdisc *, struct sk_buff *);
>> diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
>> index 961cb0f1bd0c..8f0f8e9d5475 100644
>> --- a/net/sched/sch_api.c
>> +++ b/net/sched/sch_api.c
>> @@ -999,9 +999,15 @@ static int qdisc_change(struct Qdisc *sch, struct nlattr **tca, u16 flags)
>>  	int err = 0;
>>  
>>  	if (tca[TCA_OPTIONS]) {
>> -		if (sch->ops->change == NULL)
>> -			return -EINVAL;
>> -		err = sch->ops->change(sch, tca[TCA_OPTIONS]);
>> +		if (flags & NLM_F_REPLACE) {
>> +			if (sch->ops->replace == NULL)
>> +				return -EINVAL;
>> +			err = sch->ops->replace(sch, tca[TCA_OPTIONS]);
>> +		} else {
>> +			if (sch->ops->change == NULL)
>> +				return -EINVAL;
>> +			err = sch->ops->change(sch, tca[TCA_OPTIONS]);
>> +		}
>>  		if (err)
>>  			return err;
>>  	}
> 
> NACK
> 
> This breaks existing userland scripts.

Yes, it is.

Maybe I need do some change for this code.

Thanks!

> 
> Have you tried :
> 
> tc qdisc replace dev eth0 root fq
>