2018-06-05 14:10 GMT+02:00 David Sterba <dsterba@xxxxxxx>:
> On Mon, Jun 04, 2018 at 09:31:16PM +0200, Andreas Gruenbacher wrote:
>> @@ -1062,8 +1063,9 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
>> if (ret < 0)
>> iomap_dio_set_error(dio, ret);
>>
+ /*
+ * Make sure changes to dio are visible globally before the atomic
+ * counter decrement.
+ */
>> + smp_mb__before_atomic();
>> if (!atomic_dec_and_test(&dio->ref)) {
>
> The barrier should be documented. I tried to do a quick look around the
> code if it's clear why it's there but it's not. Thanks.
>
>> - if (!is_sync_kiocb(iocb))
>> + if (!dio->wait_for_completion)
>> return -EIOCBQUEUED;
>>
>> for (;;) {
Thanks,
Andreas
