[PATCH v3 25/30] net: add rb_to_skb() and other rb tree helpers

Stephen Hemminger
2018-09-13T14:58:57Z

From: Eric Dumazet <edumazet@google.com>

Geeralize private netem_rb_to_skb()

TCP rtx queue will soon be converted to rb-tree,
so we will need skb_rbtree_walk() helpers.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 18a4c0eab2623cc95be98a1e6af1ad18e7695977)
---
include/linux/skbuff.h | 18 ++++++++++++++++++
net/ipv4/tcp_fastopen.c | 8 +++-----
net/ipv4/tcp_input.c | 33 ++++++++++++---------------------
net/sched/sch_netem.c | 14 ++++----------
4 files changed, 37 insertions(+), 36 deletions(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 758084b434c8..2837e55df03e 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -3169,6 +3169,12 @@ static inline int __skb_grow_rcsum(struct sk_buff *skb, unsigned int len)

#define rb_to_skb(rb) rb_entry_safe(rb, struct sk_buff, rbnode)

+#define rb_to_skb(rb) rb_entry_safe(rb, struct sk_buff, rbnode)
+#define skb_rb_first(root) rb_to_skb(rb_first(root))
+#define skb_rb_last(root) rb_to_skb(rb_last(root))
+#define skb_rb_next(skb) rb_to_skb(rb_next(&(skb)->rbnode))
+#define skb_rb_prev(skb) rb_to_skb(rb_prev(&(skb)->rbnode))
+
#define skb_queue_walk(queue, skb) \
for (skb = (queue)->next; \
skb != (struct sk_buff *)(queue); \
@@ -3183,6 +3189,18 @@ static inline int __skb_grow_rcsum(struct sk_buff *skb, unsigned int len)
for (; skb != (struct sk_buff *)(queue); \
skb = skb->next)

+#define skb_rbtree_walk(skb, root) \
+ for (skb = skb_rb_first(root); skb != NULL; \
+ skb = skb_rb_next(skb))
+
+#define skb_rbtree_walk_from(skb) \
+ for (; skb != NULL; \
+ skb = skb_rb_next(skb))
+
+#define skb_rbtree_walk_from_safe(skb, tmp) \
+ for (; tmp = skb ? skb_rb_next(skb) : NULL, (skb != NULL); \
+ skb = tmp)
+
#define skb_queue_walk_from_safe(queue, skb, tmp) \
for (tmp = skb->next; \
skb != (struct sk_buff *)(queue); \
diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c
index fbbeda647774..0567edb76522 100644
--- a/net/ipv4/tcp_fastopen.c
+++ b/net/ipv4/tcp_fastopen.c
@@ -458,17 +458,15 @@ bool tcp_fastopen_active_should_disable(struct sock *sk)
void tcp_fastopen_active_disable_ofo_check(struct sock *sk)
{
struct tcp_sock *tp = tcp_sk(sk);
- struct rb_node *p;
- struct sk_buff *skb;
struct dst_entry *dst;
+ struct sk_buff *skb;

if (!tp->syn_fastopen)
return;

if (!tp->data_segs_in) {
- p = rb_first(&tp->out_of_order_queue);
- if (p && !rb_next(p)) {
- skb = rb_entry(p, struct sk_buff, rbnode);
+ skb = skb_rb_first(&tp->out_of_order_queue);
+ if (skb && !skb_rb_next(skb)) {
if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) {
tcp_fastopen_active_disable(sk);
return;
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index bdabd748f4bc..991f382afc1b 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -4372,7 +4372,7 @@ static void tcp_ofo_queue(struct sock *sk)

p = rb_first(&tp->out_of_order_queue);
while (p) {
- skb = rb_entry(p, struct sk_buff, rbnode);
+ skb = rb_to_skb(p);
if (after(TCP_SKB_CB(skb)->seq, tp->rcv_nxt))
break;

@@ -4440,7 +4440,7 @@ static int tcp_try_rmem_schedule(struct sock *sk, struct sk_buff *skb,
static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb)
{
struct tcp_sock *tp = tcp_sk(sk);
- struct rb_node **p, *q, *parent;
+ struct rb_node **p, *parent;
struct sk_buff *skb1;
u32 seq, end_seq;
bool fragstolen;
@@ -4503,7 +4503,7 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb)
parent = NULL;
while (*p) {
parent = *p;
- skb1 = rb_entry(parent, struct sk_buff, rbnode);
+ skb1 = rb_to_skb(parent);
if (before(seq, TCP_SKB_CB(skb1)->seq)) {
p = &parent->rb_left;
continue;
@@ -4548,9 +4548,7 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb)

merge_right:
/* Remove other segments covered by skb. */
- while ((q = rb_next(&skb->rbnode)) != NULL) {
- skb1 = rb_entry(q, struct sk_buff, rbnode);
-
+ while ((skb1 = skb_rb_next(skb)) != NULL) {
if (!after(end_seq, TCP_SKB_CB(skb1)->seq))
break;
if (before(end_seq, TCP_SKB_CB(skb1)->end_seq)) {
@@ -4565,7 +4563,7 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb)
tcp_drop(sk, skb1);
}
/* If there is no skb after us, we are the last_skb ! */
- if (!q)
+ if (!skb1)
tp->ooo_last_skb = skb;

add_sack:
@@ -4749,7 +4747,7 @@ static struct sk_buff *tcp_skb_next(struct sk_buff *skb, struct sk_buff_head *li
if (list)
return !skb_queue_is_last(list, skb) ? skb->next : NULL;

- return rb_entry_safe(rb_next(&skb->rbnode), struct sk_buff, rbnode);
+ return skb_rb_next(skb);
}

static struct sk_buff *tcp_collapse_one(struct sock *sk, struct sk_buff *skb,
@@ -4778,7 +4776,7 @@ static void tcp_rbtree_insert(struct rb_root *root, struct sk_buff *skb)

while (*p) {
parent = *p;
- skb1 = rb_entry(parent, struct sk_buff, rbnode);
+ skb1 = rb_to_skb(parent);
if (before(TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb1)->seq))
p = &parent->rb_left;
else
@@ -4898,19 +4896,12 @@ static void tcp_collapse_ofo_queue(struct sock *sk)
struct tcp_sock *tp = tcp_sk(sk);
u32 range_truesize, sum_tiny = 0;
struct sk_buff *skb, *head;
- struct rb_node *p;
u32 start, end;

- p = rb_first(&tp->out_of_order_queue);
- skb = rb_entry_safe(p, struct sk_buff, rbnode);
+ skb = skb_rb_first(&tp->out_of_order_queue);
new_range:
if (!skb) {
- p = rb_last(&tp->out_of_order_queue);
- /* Note: This is possible p is NULL here. We do not
- * use rb_entry_safe(), as ooo_last_skb is valid only
- * if rbtree is not empty.
- */
- tp->ooo_last_skb = rb_entry(p, struct sk_buff, rbnode);
+ tp->ooo_last_skb = skb_rb_last(&tp->out_of_order_queue);
return;
}
start = TCP_SKB_CB(skb)->seq;
@@ -4918,7 +4909,7 @@ static void tcp_collapse_ofo_queue(struct sock *sk)
range_truesize = skb->truesize;

for (head = skb;;) {
- skb = tcp_skb_next(skb, NULL);
+ skb = skb_rb_next(skb);

/* Range is terminated when we see a gap or when
* we are at the queue end.
@@ -4974,7 +4965,7 @@ static bool tcp_prune_ofo_queue(struct sock *sk)
prev = rb_prev(node);
rb_erase(node, &tp->out_of_order_queue);
goal -= rb_to_skb(node)->truesize;
- tcp_drop(sk, rb_entry(node, struct sk_buff, rbnode));
+ tcp_drop(sk, rb_to_skb(node));
if (!prev || goal <= 0) {
sk_mem_reclaim(sk);
if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
@@ -4984,7 +4975,7 @@ static bool tcp_prune_ofo_queue(struct sock *sk)
}
node = prev;
} while (node);
- tp->ooo_last_skb = rb_entry(prev, struct sk_buff, rbnode);
+ tp->ooo_last_skb = rb_to_skb(prev);

/* Reset SACK state. A conforming SACK implementation will
* do the same at a timeout based retransmit. When a connection
diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index 8c8df75dbead..2a2ab6bfe5d8 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -149,12 +149,6 @@ struct netem_skb_cb {
ktime_t tstamp_save;
};

-
-static struct sk_buff *netem_rb_to_skb(struct rb_node *rb)
-{
- return rb_entry(rb, struct sk_buff, rbnode);
-}
-
static inline struct netem_skb_cb *netem_skb_cb(struct sk_buff *skb)
{
/* we assume we can use skb next/prev/tstamp as storage for rb_node */
@@ -365,7 +359,7 @@ static void tfifo_reset(struct Qdisc *sch)
struct rb_node *p;

while ((p = rb_first(&q->t_root))) {
- struct sk_buff *skb = netem_rb_to_skb(p);
+ struct sk_buff *skb = rb_to_skb(p);

rb_erase(p, &q->t_root);
rtnl_kfree_skbs(skb, skb);
@@ -382,7 +376,7 @@ static void tfifo_enqueue(struct sk_buff *nskb, struct Qdisc *sch)
struct sk_buff *skb;

parent = *p;
- skb = netem_rb_to_skb(parent);
+ skb = rb_to_skb(parent);
if (tnext >= netem_skb_cb(skb)->time_to_send)
p = &parent->rb_right;
else
@@ -538,7 +532,7 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch,
struct sk_buff *t_skb;
struct netem_skb_cb *t_last;

- t_skb = netem_rb_to_skb(rb_last(&q->t_root));
+ t_skb = skb_rb_last(&q->t_root);
t_last = netem_skb_cb(t_skb);
if (!last ||
t_last->time_to_send > last->time_to_send) {
@@ -618,7 +612,7 @@ static struct sk_buff *netem_dequeue(struct Qdisc *sch)
if (p) {
psched_time_t time_to_send;

- skb = netem_rb_to_skb(p);
+ skb = rb_to_skb(p);

/* if more time remaining? */
time_to_send = netem_skb_cb(skb)->time_to_send;
--
2.18.0