Subject: Re: [PATCH 4/7] Add "depth".

From: Michael Buesch <[email-masked]>
Date: Sun, 29 Jul 2007 20:41:45 +0200

On Sunday 29 July 2007 09:08:51 Corey Hickey wrote:
>  	p = d;
>  	n = q->dep[d].next;
> @@ -215,7 +216,7 @@ static unsigned int sfq_drop(struct Qdisc *sch)
>  	   drop a packet from it */
>  
>  	if (d > 1) {
> -		sfq_index x = q->dep[d+SFQ_DEPTH].next;
> +		sfq_index x = q->dep[d+q->depth].next;

Please q->dep[d + q->depth]
Makes it _much_ more readable. And doesn't confuse my brain with a
minus and a BiggerThan sign ;)

> @@ -383,6 +384,16 @@ static void sfq_perturbation(unsigned long arg)
>  static void sfq_q_destroy(struct sfq_sched_data *q)
>  {
>  	del_timer(&q->perturb_timer);
> +	if(q->dep)
> +		kfree(q->dep);
> +	if(q->next)
> +		kfree(q->next);
> +	if(q->allot)
> +		kfree(q->allot);
> +	if(q->hash)
> +		kfree(q->hash);
> +	if(q->qs)
> +		kfree(q->qs);

No need to check for !=NULL. kfree handles NULL.

>  }
>  
>  static void sfq_destroy(struct Qdisc *sch)
> @@ -394,6 +405,7 @@ static void sfq_destroy(struct Qdisc *sch)
>  static int sfq_q_init(struct sfq_sched_data *q, struct rtattr *opt)
>  {
>  	struct tc_sfq_qopt *ctl = RTA_DATA(opt);
> +	sfq_index p = ~0U/2;
>  	int i;
>  
>  	if (opt && opt->rta_len < RTA_LENGTH(sizeof(*ctl)))
> @@ -401,30 +413,53 @@ static int sfq_q_init(struct sfq_sched_data *q, struct rtattr *opt)
>  
>  	q->perturbation = 0;
>  	q->max_depth = 0;
> -	q->tail = q->limit = SFQ_DEPTH;
>  	if (opt == NULL) {
>  		q->perturb_period = 0;
> +		q->tail = q->limit = q->depth = SFQ_DEPTH_DEFAULT;
>  	} else {
>  		struct tc_sfq_qopt *ctl = RTA_DATA(opt);
>  		if (ctl->quantum)
>  			q->quantum = ctl->quantum;
>  		q->perturb_period = ctl->perturb_period*HZ;
> +		q->tail = q->limit = q->depth = ctl->flows ? : SFQ_DEPTH_DEFAULT;
> +
> +		if (q->depth > p - 1)
> +			return -EINVAL;

Compare depth against (~0U/2)-1? What's that doing? Should probably add a comment.

>  
>  		if (ctl->limit)
> -			q->limit = min_t(u32, ctl->limit, SFQ_DEPTH);
> +			q->limit = min_t(u32, ctl->limit, q->depth);
>  	}
>  
> +	q->dep = kmalloc((1+q->depth*2)*sizeof(struct sfq_head), GFP_KERNEL);
> +	if (!q->dep)
> +		goto err_case;
> +	q->next = kmalloc(q->depth*sizeof(sfq_index), GFP_KERNEL);
> +	if (!q->next)
> +		goto err_case;
> +	q->allot = kmalloc(q->depth*sizeof(short), GFP_KERNEL);
> +	if (!q->allot)
> +		goto err_case;
> +	q->hash = kmalloc(q->depth*sizeof(unsigned short), GFP_KERNEL);
> +	if (!q->hash)
> +		goto err_case;
> +	q->qs = kmalloc(q->depth*sizeof(struct sk_buff_head), GFP_KERNEL);
> +	if (!q->qs)
> +		goto err_case;

You may chose to use kcalloc for array allocations.

>  	for (i=0; i<SFQ_HASH_DIVISOR; i++)
> -		q->ht[i] = SFQ_DEPTH;
> -	for (i=0; i<SFQ_DEPTH; i++) {
> +		q->ht[i] = q->depth;
> +	for (i=0; i<q->depth; i++) {
>  		skb_queue_head_init(&q->qs[i]);
> -		q->dep[i+SFQ_DEPTH].next = i+SFQ_DEPTH;
> -		q->dep[i+SFQ_DEPTH].prev = i+SFQ_DEPTH;
> +		q->dep[i+q->depth].next = i+q->depth;
> +		q->dep[i+q->depth].prev = i+q->depth;
>  	}
>  
> -	for (i=0; i<SFQ_DEPTH; i++)
> +	for (i=0; i<q->depth; i++)
>  		sfq_link(q, i);
>  	return 0;
> +err_case:

This leaks a few kmallocs.

> +	sfq_q_destroy(q);
> +	return -ENOBUFS;
>  }
>  
>  static int sfq_init(struct Qdisc *sch, struct rtattr *opt)
> @@ -458,7 +493,7 @@ static int sfq_dump(struct Qdisc *sch, struct sk_buff *skb)
>  
>  	opt.limit = q->limit;
>  	opt.divisor = SFQ_HASH_DIVISOR;
> -	opt.flows = q->limit;
> +	opt.flows = q->depth;
>  
>  	RTA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
>  

-- 
Greetings Michael.