to #26323578

commit 4d7dd462971405c65bfb3821dbb6b9ce13b5e8d6 upstream.

We currently try and start the next link when we put the request, and
only if we were going to free it. This means that the optimization to
continue executing requests from the same context often fails, as we're
not putting the final reference.

Add REQ_F_LINK_NEXT to keep track of this, and allow io_uring to find the
next request more efficiently.
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Acked-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>