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tcp: support externally provided ubufs

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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 <asml.silence@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Pavel Begunkov 2022-07-12 21:52:35 +01:00 committed by Jakub Kicinski
parent 1fd3ae8c90
commit eb315a7d13
1 changed files with 22 additions and 11 deletions
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33
net/ipv4/tcp.c
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@ -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,