Commit eb315a7d authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jakub Kicinski
Browse files

tcp: support externally provided ubufs 



Teach tcp how to use external ubuf_info provided in msghdr and
also prepare it for managed frags by sprinkling
skb_zcopy_downgrade_managed() when it could mix managed and not managed
frags.

Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 1fd3ae8c

net/ipv4/tcp.c

+22 −11
Original line number Diff line number Diff line
@@ -1202,18 +1202,24 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size) 


	flags = msg->msg_flags;



	if (flags & MSG_ZEROCOPY && size && sock_flag(sk, SOCK_ZEROCOPY)) {

	if ((flags & MSG_ZEROCOPY) && size) {

		skb = tcp_write_queue_tail(sk);



		if (msg->msg_ubuf) {

			uarg = msg->msg_ubuf;

			net_zcopy_get(uarg);

			zc = sk->sk_route_caps & NETIF_F_SG;

		} else if (sock_flag(sk, SOCK_ZEROCOPY)) {

			uarg = msg_zerocopy_realloc(sk, size, skb_zcopy(skb));

			if (!uarg) {

				err = -ENOBUFS;

				goto out_err;

			}



			zc = sk->sk_route_caps & NETIF_F_SG;

			if (!zc)

				uarg->zerocopy = 0;

		}

	}



	if (unlikely(flags & MSG_FASTOPEN || inet_sk(sk)->defer_connect) &&

	    !tp->repair) {
@@ -1335,8 +1341,13 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size) 


			copy = min_t(int, copy, pfrag->size - pfrag->offset);



			if (tcp_downgrade_zcopy_pure(sk, skb) ||

			    !sk_wmem_schedule(sk, copy))

			if (unlikely(skb_zcopy_pure(skb) || skb_zcopy_managed(skb))) {

				if (tcp_downgrade_zcopy_pure(sk, skb))

					goto wait_for_space;

				skb_zcopy_downgrade_managed(skb);

			}



			if (!sk_wmem_schedule(sk, copy))

				goto wait_for_space;



			err = skb_copy_to_page_nocache(sk, &msg->msg_iter, skb,