vsock: enable setting SO_ZEROCOPY

For AF_VSOCK, zerocopy tx mode depends on transport, so this option must
be set in AF_VSOCK implementation where transport is accessible (if
transport is not set during setting SO_ZEROCOPY: for example socket is
not connected, then SO_ZEROCOPY will be enabled, but once transport will
be assigned, support of this type of transmission will be checked).

To handle SO_ZEROCOPY, AF_VSOCK implementation uses SOCK_CUSTOM_SOCKOPT
bit, thus handling SOL_SOCKET option operations, but all of them except
SO_ZEROCOPY will be forwarded to the generic handler by calling
'sock_setsockopt()'.

Signed-off-by: Arseniy Krasnov <avkrasnov@salutedevices.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 37b1c04329416e76945e1cf1f1a4474280f24a58..816725af281f388f7f21d60806670843e79b6fcc 100644 (file)
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -1406,8 +1406,16 @@ static int vsock_connect(struct socket *sock, struct sockaddr *addr,
                        goto out;
                }
 
-               if (vsock_msgzerocopy_allow(transport))
+               if (vsock_msgzerocopy_allow(transport)) {
                        set_bit(SOCK_SUPPORT_ZC, &sk->sk_socket->flags);
+               } else if (sock_flag(sk, SOCK_ZEROCOPY)) {
+                       /* If this option was set before 'connect()',
+                        * when transport was unknown, check that this
+                        * feature is supported here.
+                        */
+                       err = -EOPNOTSUPP;
+                       goto out;
+               }
 
                err = vsock_auto_bind(vsk);
                if (err)
@@ -1643,7 +1651,7 @@ static int vsock_connectible_setsockopt(struct socket *sock,
        const struct vsock_transport *transport;
        u64 val;
 
-       if (level != AF_VSOCK)
+       if (level != AF_VSOCK && level != SOL_SOCKET)
                return -ENOPROTOOPT;
 
 #define COPY_IN(_v)                                       \
@@ -1666,6 +1674,33 @@ static int vsock_connectible_setsockopt(struct socket *sock,
 
        transport = vsk->transport;
 
+       if (level == SOL_SOCKET) {
+               int zerocopy;
+
+               if (optname != SO_ZEROCOPY) {
+                       release_sock(sk);
+                       return sock_setsockopt(sock, level, optname, optval, optlen);
+               }
+
+               /* Use 'int' type here, because variable to
+                * set this option usually has this type.
+                */
+               COPY_IN(zerocopy);
+
+               if (zerocopy < 0 || zerocopy > 1) {
+                       err = -EINVAL;
+                       goto exit;
+               }
+
+               if (transport && !vsock_msgzerocopy_allow(transport)) {
+                       err = -EOPNOTSUPP;
+                       goto exit;
+               }
+
+               sock_valbool_flag(sk, SOCK_ZEROCOPY, zerocopy);
+               goto exit;
+       }
+
        switch (optname) {
        case SO_VM_SOCKETS_BUFFER_SIZE:
                COPY_IN(val);
@@ -2322,6 +2357,12 @@ static int vsock_create(struct net *net, struct socket *sock,
                }
        }
 
+       /* SOCK_DGRAM doesn't have 'setsockopt' callback set in its
+        * proto_ops, so there is no handler for custom logic.
+        */
+       if (sock_type_connectible(sock->type))
+               set_bit(SOCK_CUSTOM_SOCKOPT, &sk->sk_socket->flags);
+
        vsock_insert_unbound(vsk);
 
        return 0;