From: David Howells <dhowells@xxxxxxxxxx> Date: Wed, 7 Jun 2023 15:05:52 +0100 > Allow splice to undo the effects of MSG_MORE after prematurely ending a > splice/sendfile due to getting an EOF condition (->splice_read() returned > 0) after splice had called sendmsg() with MSG_MORE set when the user didn't > set MSG_MORE. > > For UDP, a pending packet will not be emitted if the socket is closed > before it is flushed; with this change, it be flushed by ->splice_eof(). > > For TCP, it's not clear that MSG_MORE is actually effective. > > Suggested-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> > Link: https://lore.kernel.org/r/CAHk-=wh=V579PDYvkpnTobCLGczbgxpMgGmmhqiTyE34Cpi5Gg@xxxxxxxxxxxxxx/ > Signed-off-by: David Howells <dhowells@xxxxxxxxxx> > cc: Eric Dumazet <edumazet@xxxxxxxxxx> > cc: Willem de Bruijn <willemdebruijn.kernel@xxxxxxxxx> > cc: David Ahern <dsahern@xxxxxxxxxx> > cc: "David S. Miller" <davem@xxxxxxxxxxxxx> > cc: Jakub Kicinski <kuba@xxxxxxxxxx> > cc: Paolo Abeni <pabeni@xxxxxxxxxx> > cc: Jens Axboe <axboe@xxxxxxxxx> > cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> > cc: netdev@xxxxxxxxxxxxxxx > --- > include/net/inet_common.h | 1 + > include/net/tcp.h | 1 + > include/net/udp.h | 1 + > net/ipv4/af_inet.c | 18 ++++++++++++++++++ > net/ipv4/tcp.c | 16 ++++++++++++++++ > net/ipv4/tcp_ipv4.c | 1 + > net/ipv4/udp.c | 16 ++++++++++++++++ > net/ipv6/af_inet6.c | 1 + > net/ipv6/tcp_ipv6.c | 1 + > net/ipv6/udp.c | 18 ++++++++++++++++++ > 10 files changed, 74 insertions(+) > > diff --git a/include/net/inet_common.h b/include/net/inet_common.h > index 77f4b0ef5b92..a75333342c4e 100644 > --- a/include/net/inet_common.h > +++ b/include/net/inet_common.h > @@ -35,6 +35,7 @@ void __inet_accept(struct socket *sock, struct socket *newsock, > struct sock *newsk); > int inet_send_prepare(struct sock *sk); > int inet_sendmsg(struct socket *sock, struct msghdr *msg, size_t size); > +void inet_splice_eof(struct socket *sock); > ssize_t inet_sendpage(struct socket *sock, struct page *page, int offset, > size_t size, int flags); > int inet_recvmsg(struct socket *sock, struct msghdr *msg, size_t size, > diff --git a/include/net/tcp.h b/include/net/tcp.h > index 68990a8f556a..49611af31bb7 100644 > --- a/include/net/tcp.h > +++ b/include/net/tcp.h > @@ -327,6 +327,7 @@ int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size); > int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size); > int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg, int *copied, > size_t size, struct ubuf_info *uarg); > +void tcp_splice_eof(struct socket *sock); > int tcp_sendpage(struct sock *sk, struct page *page, int offset, size_t size, > int flags); > int tcp_sendpage_locked(struct sock *sk, struct page *page, int offset, > diff --git a/include/net/udp.h b/include/net/udp.h > index 5cad44318d71..4ed0b47c5582 100644 > --- a/include/net/udp.h > +++ b/include/net/udp.h > @@ -278,6 +278,7 @@ int udp_get_port(struct sock *sk, unsigned short snum, > int udp_err(struct sk_buff *, u32); > int udp_abort(struct sock *sk, int err); > int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len); > +void udp_splice_eof(struct socket *sock); > int udp_push_pending_frames(struct sock *sk); > void udp_flush_pending_frames(struct sock *sk); > int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size); > diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c > index b5735b3551cf..6cfb78592836 100644 > --- a/net/ipv4/af_inet.c > +++ b/net/ipv4/af_inet.c > @@ -831,6 +831,21 @@ int inet_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) > } > EXPORT_SYMBOL(inet_sendmsg); > > +void inet_splice_eof(struct socket *sock) > +{ > + const struct proto *prot; > + struct sock *sk = sock->sk; > + > + if (unlikely(inet_send_prepare(sk))) > + return; > + > + /* IPV6_ADDRFORM can change sk->sk_prot under us. */ > + prot = READ_ONCE(sk->sk_prot); > + if (prot->splice_eof) > + sk->sk_prot->splice_eof(sock); We need to use prot here. > +} > +EXPORT_SYMBOL_GPL(inet_splice_eof); > + > ssize_t inet_sendpage(struct socket *sock, struct page *page, int offset, > size_t size, int flags) > { > @@ -1050,6 +1065,7 @@ const struct proto_ops inet_stream_ops = { > #ifdef CONFIG_MMU > .mmap = tcp_mmap, > #endif > + .splice_eof = inet_splice_eof, > .sendpage = inet_sendpage, > .splice_read = tcp_splice_read, > .read_sock = tcp_read_sock, > @@ -1084,6 +1100,7 @@ const struct proto_ops inet_dgram_ops = { > .read_skb = udp_read_skb, > .recvmsg = inet_recvmsg, > .mmap = sock_no_mmap, > + .splice_eof = inet_splice_eof, > .sendpage = inet_sendpage, > .set_peek_off = sk_set_peek_off, > #ifdef CONFIG_COMPAT > @@ -1115,6 +1132,7 @@ static const struct proto_ops inet_sockraw_ops = { > .sendmsg = inet_sendmsg, > .recvmsg = inet_recvmsg, > .mmap = sock_no_mmap, > + .splice_eof = inet_splice_eof, > .sendpage = inet_sendpage, > #ifdef CONFIG_COMPAT > .compat_ioctl = inet_compat_ioctl, > diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c > index 53b7751b68e1..09f03221a6f1 100644 > --- a/net/ipv4/tcp.c > +++ b/net/ipv4/tcp.c > @@ -1371,6 +1371,22 @@ int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size) > } > EXPORT_SYMBOL(tcp_sendmsg); > > +void tcp_splice_eof(struct socket *sock) > +{ > + struct sock *sk = sock->sk; > + struct tcp_sock *tp = tcp_sk(sk); > + int mss_now, size_goal; > + > + if (!tcp_write_queue_tail(sk)) > + return; > + > + lock_sock(sk); > + mss_now = tcp_send_mss(sk, &size_goal, 0); > + tcp_push(sk, 0, mss_now, tp->nonagle, size_goal); > + release_sock(sk); > +} > +EXPORT_SYMBOL_GPL(tcp_splice_eof); > + > /* > * Handle reading urgent data. BSD has very simple semantics for > * this, no blocking and very strange errors 8) > diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c > index 53e9ce2f05bb..84a5d557dc1a 100644 > --- a/net/ipv4/tcp_ipv4.c > +++ b/net/ipv4/tcp_ipv4.c > @@ -3116,6 +3116,7 @@ struct proto tcp_prot = { > .keepalive = tcp_set_keepalive, > .recvmsg = tcp_recvmsg, > .sendmsg = tcp_sendmsg, > + .splice_eof = tcp_splice_eof, > .sendpage = tcp_sendpage, > .backlog_rcv = tcp_v4_do_rcv, > .release_cb = tcp_release_cb, > diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c > index fd3dae081f3a..df5e407286d7 100644 > --- a/net/ipv4/udp.c > +++ b/net/ipv4/udp.c > @@ -1324,6 +1324,21 @@ int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) > } > EXPORT_SYMBOL(udp_sendmsg); > > +void udp_splice_eof(struct socket *sock) > +{ > + struct sock *sk = sock->sk; > + struct udp_sock *up = udp_sk(sk); > + > + if (!up->pending || READ_ONCE(up->corkflag)) > + return; > + > + lock_sock(sk); > + if (up->pending && !READ_ONCE(up->corkflag)) > + udp_push_pending_frames(sk); > + release_sock(sk); > +} > +EXPORT_SYMBOL_GPL(udp_splice_eof); > + > int udp_sendpage(struct sock *sk, struct page *page, int offset, > size_t size, int flags) > { > @@ -2918,6 +2933,7 @@ struct proto udp_prot = { > .getsockopt = udp_getsockopt, > .sendmsg = udp_sendmsg, > .recvmsg = udp_recvmsg, > + .splice_eof = udp_splice_eof, > .sendpage = udp_sendpage, > .release_cb = ip4_datagram_release_cb, > .hash = udp_lib_hash, > diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c > index 2bbf13216a3d..564942bee067 100644 > --- a/net/ipv6/af_inet6.c > +++ b/net/ipv6/af_inet6.c > @@ -695,6 +695,7 @@ const struct proto_ops inet6_stream_ops = { > #ifdef CONFIG_MMU > .mmap = tcp_mmap, > #endif > + .splice_eof = inet_splice_eof, > .sendpage = inet_sendpage, > .sendmsg_locked = tcp_sendmsg_locked, > .sendpage_locked = tcp_sendpage_locked, > diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c > index d657713d1c71..c17c8ff94b79 100644 > --- a/net/ipv6/tcp_ipv6.c > +++ b/net/ipv6/tcp_ipv6.c > @@ -2150,6 +2150,7 @@ struct proto tcpv6_prot = { > .keepalive = tcp_set_keepalive, > .recvmsg = tcp_recvmsg, > .sendmsg = tcp_sendmsg, > + .splice_eof = tcp_splice_eof, > .sendpage = tcp_sendpage, > .backlog_rcv = tcp_v6_do_rcv, > .release_cb = tcp_release_cb, > diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c > index e5a337e6b970..6c5975b13ae3 100644 > --- a/net/ipv6/udp.c > +++ b/net/ipv6/udp.c > @@ -1653,6 +1653,23 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) > } > EXPORT_SYMBOL(udpv6_sendmsg); > > +static void udpv6_splice_eof(struct socket *sock) > +{ > + struct sock *sk = sock->sk; > + struct udp_sock *up = udp_sk(sk); > + > + if (!up->pending || READ_ONCE(up->corkflag)) > + return; > + > + if (up->pending == AF_INET) > + udp_splice_eof(sock); Do we need this ? > + > + lock_sock(sk); > + if (up->pending && !READ_ONCE(up->corkflag)) > + udp_push_pending_frames(sk); We should use udp_v6_push_pending_frames(sk) as up->pending could be AF_INET even after the test above. > + release_sock(sk); > +} > + > void udpv6_destroy_sock(struct sock *sk) > { > struct udp_sock *up = udp_sk(sk); > @@ -1764,6 +1781,7 @@ struct proto udpv6_prot = { > .getsockopt = udpv6_getsockopt, > .sendmsg = udpv6_sendmsg, > .recvmsg = udpv6_recvmsg, > + .splice_eof = udpv6_splice_eof, > .release_cb = ip6_datagram_release_cb, > .hash = udp_lib_hash, > .unhash = udp_lib_unhash,
