io_uring/net: fix non-zc send with address

We're currently ignoring the dest address with non-zerocopy send because
even though we copy it from the userspace shortly after ->msg_name gets
zeroed. Move msghdr init earlier.

Fixes: 516e82f ("io_uring/net: support non-zerocopy sendto")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/176ced5e8568aa5d300ca899b7f05b303ebc49fd.1664409532.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring/net.c

@@ -333,6 +333,12 @@ int io_send(struct io_kiocb *req, unsigned int issue_flags)
 	int min_ret = 0;
 	int ret;
 
+	msg.msg_name = NULL;
+	msg.msg_control = NULL;
+	msg.msg_controllen = 0;
+	msg.msg_namelen = 0;
+	msg.msg_ubuf = NULL;
+
 	if (sr->addr) {
 		if (req_has_async_data(req)) {
 			struct io_async_msghdr *io = req->async_data;
@@ -359,12 +365,6 @@ int io_send(struct io_kiocb *req, unsigned int issue_flags)
 	if (unlikely(ret))
 		return ret;
 
-	msg.msg_name = NULL;
-	msg.msg_control = NULL;
-	msg.msg_controllen = 0;
-	msg.msg_namelen = 0;
-	msg.msg_ubuf = NULL;
-
 	flags = sr->msg_flags;
 	if (issue_flags & IO_URING_F_NONBLOCK)
 		flags |= MSG_DONTWAIT;