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tcp: add tcp_ooo_try_coalesce() helper 

In case skb in out_or_order_queue is the result of
multiple skbs coalescing, we would like to get a proper gso_segs
counter tracking, so that future tcp_drop() can report an accurate
number.

I chose to not implement this tracking for skbs in receive queue,
since they are not dropped, unless socket is disconnected.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2018-07-23 09:28:21 -07:00 committed by David S. Miller
parent 8541b21e78
commit 58152ecbbc
1 changed files with 21 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
net/ipv4/tcp_input.c
View File

@ -4358,6 +4358,23 @@ static bool tcp_try_coalesce(struct sock *sk,
return true;
}
static bool tcp_ooo_try_coalesce(struct sock *sk,
struct sk_buff *to,
struct sk_buff *from,
bool *fragstolen)
{
bool res = tcp_try_coalesce(sk, to, from, fragstolen);
/* In case tcp_drop() is called later, update to->gso_segs */
if (res) {
u32 gso_segs = max_t(u16, 1, skb_shinfo(to)->gso_segs) +
max_t(u16, 1, skb_shinfo(from)->gso_segs);
skb_shinfo(to)->gso_segs = min_t(u32, gso_segs, 0xFFFF);
}
return res;
}
static void tcp_drop(struct sock *sk, struct sk_buff *skb)
{
sk_drops_add(sk, skb);
@ -4481,7 +4498,7 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb)
/* In the typical case, we are adding an skb to the end of the list.
* Use of ooo_last_skb avoids the O(Log(N)) rbtree lookup.
*/
if (tcp_try_coalesce(sk, tp->ooo_last_skb,
if (tcp_ooo_try_coalesce(sk, tp->ooo_last_skb,
skb, &fragstolen)) {
coalesce_done:
tcp_grow_window(sk, skb);
@ -4532,7 +4549,7 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb)
tcp_drop(sk, skb1);
goto merge_right;
}
} else if (tcp_try_coalesce(sk, skb1,
} else if (tcp_ooo_try_coalesce(sk, skb1,
skb, &fragstolen)) {
goto coalesce_done;
}