[PATCH net-next v4 11/27] tcp: support externally provided ubufs
From: Pavel Begunkov <asml.silence@gmail.com>
Date: 2022-07-07 11:52:42
Also in:
io-uring, lkml
Subsystem:
networking [general], networking [tcp], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Neal Cardwell, Linus Torvalds
Teach ipv4/udp 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 <asml.silence@gmail.com> --- net/ipv4/tcp.c | 32 ++++++++++++++++++++------------ 1 file changed, 20 insertions(+), 12 deletions(-)
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 390eb3dc53bd..a81f694af5e9 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c@@ -1223,17 +1223,23 @@ 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) &&
@@ -1356,9 +1362,11 @@ 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)) - goto wait_for_space; - + 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); + } copy = tcp_wmem_schedule(sk, copy); if (!copy) goto wait_for_space;
--
2.36.1