io_uring/net: copy addr for zc on POLL_FIRST

Every time we return from an issue handler and expect the request to be
retried we should also setup it for async exec ourselves. Do that when
we return on IORING_RECVSEND_POLL_FIRST in io_sendzc(), otherwise it'll
re-read the address, which might be a surprise for the userspace.

Fixes: 092aeedb ("io_uring: allow to pass addr into sendzc")
Signed-off-by: NPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/ab1d0657890d6721339c56d2e161a4bba06f85d0.1662642013.git.asml.silence@gmail.comSigned-off-by: NJens Axboe <axboe@kernel.dk>

io_uring/net.c

@@ -1003,9 +1003,6 @@ int io_sendzc(struct io_kiocb *req, unsigned int issue_flags)
 	unsigned msg_flags, cflags;
 	int ret, min_ret = 0;
 
-	if (!(req->flags & REQ_F_POLLED) &&
-	    (zc->flags & IORING_RECVSEND_POLL_FIRST))
-		return -EAGAIN;
 	sock = sock_from_file(req->file);
 	if (unlikely(!sock))
 		return -ENOTSOCK;
@@ -1030,6 +1027,10 @@ int io_sendzc(struct io_kiocb *req, unsigned int issue_flags)
 		msg.msg_namelen = zc->addr_len;
 	}
 
+	if (!(req->flags & REQ_F_POLLED) &&
+	    (zc->flags & IORING_RECVSEND_POLL_FIRST))
+		return io_setup_async_addr(req, addr, issue_flags);
+
 	if (zc->flags & IORING_RECVSEND_FIXED_BUF) {
 		ret = io_import_fixed(WRITE, &msg.msg_iter, req->imu,
 					(u64)(uintptr_t)zc->buf, zc->len);