net: flag sockets supporting msghdr originated zerocopy

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: <[email protected]> # 6.0 Signed-off-by: Pavel Begunkov <[email protected]> Acked-by: Jakub Kicinski <[email protected]> Link: https://lore.kernel.org/r/3dafafab822b1c66308bb58a0ac738b1e3f53f74.1666346426.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <[email protected]>
chewitt · Oct 22, 2022 · e993ffe · e993ffe
1 parent 996d3ef
commit e993ffe
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diff --git 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
 /**

diff --git 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);

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
@@ -1624,6 +1624,7 @@ 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;
 }