aio-posix: don't pass ns timeout to epoll_wait()

Don't pass the nanosecond timeout into epoll_wait(), which expects
milliseconds.

The epoll_wait() timeout value does not matter if qemu_poll_ns()
determined that the poll fd is ready, but passing a value in the wrong
units is still ugly.  Pass a 0 timeout to epoll_wait() instead.
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NSergio Lopez <slp@redhat.com>
Message-id: 20200214171712.541358-3-stefanha@redhat.com
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

util/aio-posix.c

@@ -117,6 +117,9 @@ static int aio_epoll(AioContext *ctx, int64_t timeout)
 
     if (timeout > 0) {
         ret = qemu_poll_ns(&pfd, 1, timeout);
+        if (ret > 0) {
+            timeout = 0;
+        }
     }
     if (timeout <= 0 || ret > 0) {
         ret = epoll_wait(ctx->epollfd, events,