[PATCH 6/7] [PKT_SCHED]: Cleanup pfifo_fast qdisc and remove unnecessary code

[Thomas Graf <tgraf@xxxxxxx>]

Removes the skb trimming code which is not needed since we never
touch the skb upon failure. Removes unnecessary initializers,
and simplifies the code a bit.

Signed-off-by: Thomas Graf <tgraf@xxxxxxx>

Index: net-2.6.13/net/sched/sch_generic.c
===================================================================
--- net-2.6.13.orig/net/sched/sch_generic.c
+++ net-2.6.13/net/sched/sch_generic.c
@@ -311,6 +311,8 @@ static const u8 prio2band[TC_PRIO_MAX+1]
    generic prio+fifo combination.
  */
 
+#define PFIFO_FAST_BANDS 3
+
 static inline struct sk_buff_head *prio2list(struct sk_buff *skb,
                                             struct Qdisc *qdisc)
 {
@@ -318,8 +320,7 @@ static inline struct sk_buff_head *prio2
        return list + prio2band[skb->priority & TC_PRIO_MAX];
 }
 
-static int
-pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc* qdisc)
+static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc* qdisc)
 {
        struct sk_buff_head *list = prio2list(skb, qdisc);
 
@@ -331,36 +332,34 @@ pfifo_fast_enqueue(struct sk_buff *skb, 
        return qdisc_drop(skb, qdisc);
 }
 
-static struct sk_buff *
-pfifo_fast_dequeue(struct Qdisc* qdisc)
+static struct sk_buff *pfifo_fast_dequeue(struct Qdisc* qdisc)
 {
        int prio;
        struct sk_buff_head *list = qdisc_priv(qdisc);
 
-       for (prio = 0; prio < 3; prio++, list++) {
+       for (prio = 0; prio < PFIFO_FAST_BANDS; prio++, list++) {
                struct sk_buff *skb = __qdisc_dequeue_head(qdisc, list);
                if (skb) {
                        qdisc->q.qlen--;
                        return skb;
                }
        }
+
        return NULL;
 }
 
-static int
-pfifo_fast_requeue(struct sk_buff *skb, struct Qdisc* qdisc)
+static int pfifo_fast_requeue(struct sk_buff *skb, struct Qdisc* qdisc)
 {
        qdisc->q.qlen++;
        return __qdisc_requeue(skb, qdisc, prio2list(skb, qdisc));
 }
 
-static void
-pfifo_fast_reset(struct Qdisc* qdisc)
+static void pfifo_fast_reset(struct Qdisc* qdisc)
 {
        int prio;
        struct sk_buff_head *list = qdisc_priv(qdisc);
 
-       for (prio=0; prio < 3; prio++)
+       for (prio = 0; prio < PFIFO_FAST_BANDS; prio++)
                __qdisc_reset_queue(qdisc, list + prio);
 
        qdisc->qstats.backlog = 0;
@@ -369,35 +368,30 @@ pfifo_fast_reset(struct Qdisc* qdisc)
 
 static int pfifo_fast_dump(struct Qdisc *qdisc, struct sk_buff *skb)
 {
-       unsigned char    *b = skb->tail;
-       struct tc_prio_qopt opt;
+       struct tc_prio_qopt opt = { .bands = PFIFO_FAST_BANDS };
 
-       opt.bands = 3; 
        memcpy(&opt.priomap, prio2band, TC_PRIO_MAX+1);
        RTA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
        return skb->len;
 
 rtattr_failure:
-       skb_trim(skb, b - skb->data);
        return -1;
 }
 
 static int pfifo_fast_init(struct Qdisc *qdisc, struct rtattr *opt)
 {
-       int i;
+       int prio;
        struct sk_buff_head *list = qdisc_priv(qdisc);
 
-       for (i=0; i<3; i++)
-               skb_queue_head_init(list+i);
+       for (prio = 0; prio < PFIFO_FAST_BANDS; prio++)
+               skb_queue_head_init(list + prio);
 
        return 0;
 }
 
 static struct Qdisc_ops pfifo_fast_ops = {
-       .next           =       NULL,
-       .cl_ops         =       NULL,
        .id             =       "pfifo_fast",
-       .priv_size      =       3 * sizeof(struct sk_buff_head),
+       .priv_size      =       PFIFO_FAST_BANDS * sizeof(struct sk_buff_head),
        .enqueue        =       pfifo_fast_enqueue,
        .dequeue        =       pfifo_fast_dequeue,
        .requeue        =       pfifo_fast_requeue,