Commit 8ddab508 authored by Willem de Bruijn's avatar Willem de Bruijn Committed by David S. Miller
Browse files

tcp: do not allocate linear memory for zerocopy skbs 



Zerocopy payload is now always stored in frags, and space for headers
is reversed, so this memory is unused.

Signed-off-by: default avatarWillem de Bruijn <willemb@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 02583ade

net/ipv4/tcp.c

+7 −4
Original line number Diff line number Diff line
@@ -1104,12 +1104,15 @@ static int linear_payload_sz(bool first_skb) 
	return 0;

}



static int select_size(const struct sock *sk, bool sg, bool first_skb)

static int select_size(const struct sock *sk, bool sg, bool first_skb, bool zc)

{

	const struct tcp_sock *tp = tcp_sk(sk);

	int tmp = tp->mss_cache;



	if (sg) {

		if (zc)

			return 0;



		if (sk_can_gso(sk)) {

			tmp = linear_payload_sz(first_skb);

		} else {
@@ -1282,6 +1285,7 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size) 


		if (copy <= 0 || !tcp_skb_can_collapse_to(skb)) {

			bool first_skb;

			int linear;



new_segment:

			/* Allocate new segment. If the interface is SG,
@@ -1295,9 +1299,8 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size) 
				goto restart;

			}

			first_skb = tcp_rtx_and_write_queues_empty(sk);

			skb = sk_stream_alloc_skb(sk,

						  select_size(sk, sg, first_skb),

						  sk->sk_allocation,

			linear = select_size(sk, sg, first_skb, zc);

			skb = sk_stream_alloc_skb(sk, linear, sk->sk_allocation,

						  first_skb);

			if (!skb)

				goto wait_for_memory;