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); +} +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); + + lock_sock(sk); + if (up->pending && !READ_ONCE(up->corkflag)) + udp_push_pending_frames(sk); + 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,
