io_uring: honor IOSQE_ASYNC for linked reqs

to #26323588

commit 86a761f81ec87a96572214f5db606f60d36aaf08 upstream.

REQ_F_FORCE_ASYNC is checked only for the head of a link. Fix it.
Signed-off-by: NPavel Begunkov <asml.silence@gmail.com>
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>

fs/io_uring.c

@@ -4509,6 +4509,7 @@ static void __io_queue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 	 */
 	if (ret == -EAGAIN && (!(req->flags & REQ_F_NOWAIT) ||
 	    (req->flags & REQ_F_MUST_PUNT))) {
+punt:
 		if (req->work.flags & IO_WQ_WORK_NEEDS_FILES) {
 			ret = io_grab_files(req);
 			if (ret)
@@ -4544,6 +4545,9 @@ static void __io_queue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 	if (nxt) {
 		req = nxt;
 		nxt = NULL;
+
+		if (req->flags & REQ_F_FORCE_ASYNC)
+			goto punt;
 		goto again;
 	}
 }