[RFC PATCH v2 15/21] net/tcp: add MSG_NETDMA flag for sendmsg()
From: Jonathan Lemon <hidden>
Date: 2020-07-27 22:45:23
Subsystem:
networking [general], networking [sockets], networking [tcp], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Kuniyuki Iwashima, Willem de Bruijn, Neal Cardwell, Linus Torvalds
This flag indicates that the attached data is a zero-copy send, and the pages should be retrieved from the netgpu module. The socket should should already have been attached to a netgpu queue. Signed-off-by: Jonathan Lemon <redacted> --- include/linux/socket.h | 1 + net/ipv4/tcp.c | 8 ++++++++ 2 files changed, 9 insertions(+)
diff --git a/include/linux/socket.h b/include/linux/socket.h
index 04d2bc97f497..63816cc25dee 100644
--- a/include/linux/socket.h
+++ b/include/linux/socket.h@@ -310,6 +310,7 @@ struct ucred { */ #define MSG_ZEROCOPY 0x4000000 /* Use user data in kernel path */ +#define MSG_NETDMA 0x8000000 #define MSG_FASTOPEN 0x20000000 /* Send data in TCP SYN */ #define MSG_CMSG_CLOEXEC 0x40000000 /* Set close_on_exec for file descriptor received through
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 261c28ccc8f6..340ce319edc9 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c@@ -1214,6 +1214,14 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size) uarg->zerocopy = 0; } + if (flags & MSG_NETDMA && size && sock_flag(sk, SOCK_ZEROCOPY)) { + zc = sk->sk_route_caps & NETIF_F_SG; + if (!zc) { + err = -EFAULT; + goto out_err; + } + } + if (unlikely(flags & MSG_FASTOPEN || inet_sk(sk)->defer_connect) && !tp->repair) { err = tcp_sendmsg_fastopen(sk, msg, &copied_syn, size, uarg);
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2.24.1