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

Commit 02583ade authored by Willem de Bruijn's avatar Willem de Bruijn Committed by David S. Miller
Browse files

tcp: place all zerocopy payload in frags 



This avoids an unnecessary copy of 1-2KB and improves tso_fragment,
which has to fall back to tcp_fragment if skb->len != skb_data_len.

It also avoids a surprising inconsistency in notifications:
Zerocopy packets sent over loopback have their frags copied, so set
SO_EE_CODE_ZEROCOPY_COPIED in the notification. But this currently
does not happen for small packets, because when all data fits in the
linear fragment, data is not copied in skb_orphan_frags_rx.

Reported-by: default avatarTom Deseyn <tom.deseyn@gmail.com>
Signed-off-by: default avatarWillem de Bruijn <willemb@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 111856c7

net/ipv4/tcp.c

+5 −4
Original line number Diff line number Diff line
@@ -1186,7 +1186,7 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size) 
	int flags, err, copied = 0;

	int mss_now = 0, size_goal, copied_syn = 0;

	bool process_backlog = false;

	bool sg;

	bool sg, zc = false;

	long timeo;



	flags = msg->msg_flags;
@@ -1204,7 +1204,8 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size) 
			goto out_err;

		}



		if (!(sk_check_csum_caps(sk) && sk->sk_route_caps & NETIF_F_SG))

		zc = sk_check_csum_caps(sk) && sk->sk_route_caps & NETIF_F_SG;

		if (!zc)

			uarg->zerocopy = 0;

	}
@@ -1325,13 +1326,13 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size) 
			copy = msg_data_left(msg);



		/* Where to copy to? */

		if (skb_availroom(skb) > 0) {

		if (skb_availroom(skb) > 0 && !zc) {

			/* We have some space in skb head. Superb! */

			copy = min_t(int, copy, skb_availroom(skb));

			err = skb_add_data_nocache(sk, skb, &msg->msg_iter, copy);

			if (err)

				goto do_fault;

		} else if (!uarg || !uarg->zerocopy) {

		} else if (!zc) {

			bool merge = true;

			int i = skb_shinfo(skb)->nr_frags;

			struct page_frag *pfrag = sk_page_frag(sk);