[PATCH 6.0 08/20] net: flag sockets supporting msghdr originated zerocopy

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Pavel Begunkov <asml.silence@gmail.com>

commit e993ffe3da4bcddea0536b03be1031bf35cd8d85 upstream.

We need an efficient way in io_uring to check whether a socket supports
zerocopy with msghdr provided ubuf_info. Add a new flag into the struct
socket flags fields.

Cc: <stable@vger.kernel.org> # 6.0
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/3dafafab822b1c66308bb58a0ac738b1e3f53f74.1666346426.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 include/linux/net.h |    1 +
 net/ipv4/tcp.c      |    1 +
 net/ipv4/udp.c      |    1 +
 3 files changed, 3 insertions(+)

--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -41,6 +41,7 @@ struct net;
 #define SOCK_NOSPACE		2
 #define SOCK_PASSCRED		3
 #define SOCK_PASSSEC		4
+#define SOCK_SUPPORT_ZC		5
 
 #ifndef ARCH_HAS_SOCKET_TYPES
 /**
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -457,6 +457,7 @@ void tcp_init_sock(struct sock *sk)
 	WRITE_ONCE(sk->sk_sndbuf, READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_wmem[1]));
 	WRITE_ONCE(sk->sk_rcvbuf, READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_rmem[1]));
 
+	set_bit(SOCK_SUPPORT_ZC, &sk->sk_socket->flags);
 	sk_sockets_allocated_inc(sk);
 }
 EXPORT_SYMBOL(tcp_init_sock);
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1620,6 +1620,7 @@ int udp_init_sock(struct sock *sk)
 {
 	skb_queue_head_init(&udp_sk(sk)->reader_queue);
 	sk->sk_destruct = udp_destruct_sock;
+	set_bit(SOCK_SUPPORT_ZC, &sk->sk_socket->flags);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(udp_init_sock);