From eb315a7d1396b1139fc7daea55f2d3191e8e7092 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Tue, 12 Jul 2022 21:52:35 +0100 Subject: [PATCH] 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: Pavel Begunkov Signed-off-by: Jakub Kicinski --- net/ipv4/tcp.c | 33 ++++++++++++++++++++++----------- 1 file changed, 22 insertions(+), 11 deletions(-) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 028513d..fdb80b9 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1202,17 +1202,23 @@ 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); - 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 (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) && @@ -1335,8 +1341,13 @@ new_segment: 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, -- 2.7.4