[RFC] do_iopoll() and *grab_env()

[Pavel Begunkov <asml.silence@gmail.com>]

io_do_iopoll() can async punt a request with io_queue_async_work(),
so doing io_req_work_grab_env(). The problem is that iopoll() can
be called from who knows what context, e.g. from a completely
different process with its own memory space, creds, etc.

io_do_iopoll() {
	ret = req->poll();
	if (ret == -EAGAIN)
		io_queue_async_work()
	...
}


I can't find it handled in io_uring. Can this even happen?
Wouldn't it be better to complete them with -EAGAIN?

-- 
Pavel Begunkov