Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit b2532eb9 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

tcp: fix ooo_okay setting vs Small Queues 



TCP Small Queues (tcp_tsq_handler()) can hold one reference on
sk->sk_wmem_alloc, preventing skb->ooo_okay being set.

We should relax test done to set skb->ooo_okay to take care
of this extra reference.

Minimal truesize of skb containing one byte of payload is
SKB_TRUESIZE(1)

Without this fix, we have more chance locking flows into the wrong
transmit queue.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 31eff81e

net/ipv4/tcp_output.c

+6 −2
Original line number Diff line number Diff line
@@ -914,9 +914,13 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it, 
		tcp_ca_event(sk, CA_EVENT_TX_START);



	/* if no packet is in qdisc/device queue, then allow XPS to select

	 * another queue.

	 * another queue. We can be called from tcp_tsq_handler()

	 * which holds one reference to sk_wmem_alloc.

	 *

	 * TODO: Ideally, in-flight pure ACK packets should not matter here.

	 * One way to get this would be to set skb->truesize = 2 on them.

	 */

	skb->ooo_okay = sk_wmem_alloc_get(sk) == 0;

	skb->ooo_okay = sk_wmem_alloc_get(sk) < SKB_TRUESIZE(1);



	skb_push(skb, tcp_header_size);

	skb_reset_transport_header(skb);