diff options
| -rw-r--r-- | include/linux/skbuff.h | 20 | ||||
| -rw-r--r-- | net/sched/sch_netem.c | 27 |
2 files changed, 20 insertions, 27 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 6c8b6f604e76..5ad9675b6fe1 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -20,6 +20,7 @@ #include <linux/time.h> #include <linux/bug.h> #include <linux/cache.h> +#include <linux/rbtree.h> #include <linux/atomic.h> #include <asm/types.h> @@ -440,6 +441,7 @@ static inline u32 skb_mstamp_us_delta(const struct skb_mstamp *t1, * @next: Next buffer in list * @prev: Previous buffer in list * @tstamp: Time we arrived/left + * @rbnode: RB tree node, alternative to next/prev for netem/tcp * @sk: Socket we are owned by * @dev: Device we arrived on/are leaving by * @cb: Control buffer. Free for use by every layer. Put private vars here @@ -504,15 +506,19 @@ static inline u32 skb_mstamp_us_delta(const struct skb_mstamp *t1, */ struct sk_buff { - /* These two members must be first. */ - struct sk_buff *next; - struct sk_buff *prev; - union { - ktime_t tstamp; - struct skb_mstamp skb_mstamp; + struct { + /* These two members must be first. */ + struct sk_buff *next; + struct sk_buff *prev; + + union { + ktime_t tstamp; + struct skb_mstamp skb_mstamp; + }; + }; + struct rb_node rbnode; /* used in netem & tcp stack */ }; - struct sock *sk; struct net_device *dev; diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c index b34331967e02..179f1c8c0d8b 100644 --- a/net/sched/sch_netem.c +++ b/net/sched/sch_netem.c @@ -139,33 +139,20 @@ struct netem_sched_data { /* Time stamp put into socket buffer control block * Only valid when skbs are in our internal t(ime)fifo queue. + * + * As skb->rbnode uses same storage than skb->next, skb->prev and skb->tstamp, + * and skb->next & skb->prev are scratch space for a qdisc, + * we save skb->tstamp value in skb->cb[] before destroying it. */ struct netem_skb_cb { psched_time_t time_to_send; ktime_t tstamp_save; }; -/* Because space in skb->cb[] is tight, netem overloads skb->next/prev/tstamp - * to hold a rb_node structure. - * - * If struct sk_buff layout is changed, the following checks will complain. - */ -static struct rb_node *netem_rb_node(struct sk_buff *skb) -{ - BUILD_BUG_ON(offsetof(struct sk_buff, next) != 0); - BUILD_BUG_ON(offsetof(struct sk_buff, prev) != - offsetof(struct sk_buff, next) + sizeof(skb->next)); - BUILD_BUG_ON(offsetof(struct sk_buff, tstamp) != - offsetof(struct sk_buff, prev) + sizeof(skb->prev)); - BUILD_BUG_ON(sizeof(struct rb_node) > sizeof(skb->next) + - sizeof(skb->prev) + - sizeof(skb->tstamp)); - return (struct rb_node *)&skb->next; -} static struct sk_buff *netem_rb_to_skb(struct rb_node *rb) { - return (struct sk_buff *)rb; + return container_of(rb, struct sk_buff, rbnode); } static inline struct netem_skb_cb *netem_skb_cb(struct sk_buff *skb) @@ -403,8 +390,8 @@ static void tfifo_enqueue(struct sk_buff *nskb, struct Qdisc *sch) else p = &parent->rb_left; } - rb_link_node(netem_rb_node(nskb), parent, p); - rb_insert_color(netem_rb_node(nskb), &q->t_root); + rb_link_node(&nskb->rbnode, parent, p); + rb_insert_color(&nskb->rbnode, &q->t_root); sch->q.qlen++; } |