io_uring/net: fail zc sendmsg when unsupported by socket

The previous patch fails zerocopy send requests for protocols that don't
support it, do the same for zerocopy sendmsg.

Signed-off-by: Pavel Begunkov <[email protected]>
Link: https://lore.kernel.org/r/0854e7bb4c3d810a48ec8b5853e2f61af36a0467.1666346426.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <[email protected]>

Author: isilence

io_uring/net.c

@@ -1153,6 +1153,8 @@ int io_sendmsg_zc(struct io_kiocb *req, unsigned int issue_flags)
 	sock = sock_from_file(req->file);
 	if (unlikely(!sock))
 		return -ENOTSOCK;
+	if (!test_bit(SOCK_SUPPORT_ZC, &sock->flags))
+		return -EOPNOTSUPP;
 
 	if (req_has_async_data(req)) {
 		kmsg = req->async_data;