io_uring: add missing io_req_cancelled()

mainline inclusion
from mainline-5.6-rc3
commit 7fbeb95d
category: feature
bugzilla: https://bugzilla.openeuler.org/show_bug.cgi?id=27
CVE: NA
---------------------------

fallocate_finish() is missing cancellation check. Add it.
It's safe to do that, as only flags setup and sqe fields copy are done
before it gets into __io_fallocate().
Signed-off-by: NPavel Begunkov <asml.silence@gmail.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: Nyangerkun <yangerkun@huawei.com>
Reviewed-by: Nzhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: NCheng Jian <cj.chengjian@huawei.com>

fs/io_uring.c

@@ -2511,6 +2511,9 @@ static void io_fallocate_finish(struct io_wq_work **workptr)
 	struct io_kiocb *nxt = NULL;
 	int ret;
 
+	if (io_req_cancelled(req))
+		return;
+
 	ret = vfs_fallocate(req->file, req->sync.mode, req->sync.off,
 				req->sync.len);
 	if (ret < 0)
@@ -2850,6 +2853,7 @@ static void io_close_finish(struct io_wq_work **workptr)
 	struct io_kiocb *req = container_of(*workptr, struct io_kiocb, work);
 	struct io_kiocb *nxt = NULL;
 
+	/* not cancellable, don't do io_req_cancelled() */
 	__io_close_finish(req, &nxt);
 	if (nxt)
 		io_wq_assign_next(workptr, nxt);