On 11/7/19 2:53 AM, Pavel Begunkov wrote:
>> @@ -804,8 +803,10 @@ static void io_fail_links(struct io_kiocb *req)
>> link->submit.sqe->opcode == IORING_OP_LINK_TIMEOUT) {
>> io_link_cancel_timeout(ctx, link);
>> } else {
>> - io_cqring_fill_event(ctx, link->user_data, -ECANCELED);
>> - __io_free_req(link);
>> + io_cqring_fill_event(link, -ECANCELED);
>> + /* drop both submit and complete references */
>> + io_put_req(link, NULL);
>> + io_put_req(link, NULL);
>
> io_put_req() -> ... -> io_free_req() -> io_fail_links() -> io_put_req()
>
> It shouldn't recurse further, but probably it would be better to avoid
> it at all.
Not sure how to improve that. We could do something ala:
if (refcount_sub_and_test(2, &link->refs))
__io_free_req(link);
to make it clear and more resistant against recursion.
I also think we need to put that link path out-of-line in io_free_req().
I'll make those two changes.
--
Jens Axboe
