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Commit 36ee106e authored by Eric Dumazet's avatar Eric Dumazet Committed by Greg Kroah-Hartman
Browse files

tcp: add tcp_ooo_try_coalesce() helper 



commit 58152ecbbcc6a0ce7fddd5bf5f6ee535834ece0c upstream.

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: default avatarEric Dumazet <edumazet@google.com>
Acked-by: default avatarSoheil Hassas Yeganeh <soheil@google.com>
Acked-by: default avatarYuchung Cheng <ycheng@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarDavid Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent b2486a81

net/ipv4/tcp_input.c

+21 −2
Original line number Diff line number Diff line
@@ -4370,6 +4370,23 @@ 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);
@@ -4493,7 +4510,8 @@ 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, skb, &fragstolen)) {

	if (tcp_ooo_try_coalesce(sk, tp->ooo_last_skb,

				 skb, &fragstolen)) {

coalesce_done:

		tcp_grow_window(sk, skb);

		kfree_skb_partial(skb, fragstolen);
@@ -4543,7 +4561,8 @@ 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, skb, &fragstolen)) {

		} else if (tcp_ooo_try_coalesce(sk, skb1,

						skb, &fragstolen)) {

			goto coalesce_done;

		}

		p = &parent->rb_right;