[PATCH v3 2/3] mmc: core: add random fault injection

[Per Forlin]

On 25 July 2011 17:58, Akinobu Mita <akinobu.mita at gmail.com> wrote:
> 2011/7/21 Per Forlin <per.forlin at linaro.org>:
>> This adds support to inject data errors after a completed host transfer.
>> The mmc core will return error even though the host transfer is successful.
>> This simple fault injection proved to be very useful to test the
>> non-blocking error handling in the mmc_blk_issue_rw_rq().
>> Random faults can also test how the host driver handles pre_req()
>> and post_req() in case of errors.
>
> Looks good to me.
>
>> @@ -82,6 +87,66 @@ static void mmc_flush_scheduled_work(void)
>>        flush_workqueue(workqueue);
>>  }
>>
>> +#ifdef CONFIG_FAIL_MMC_REQUEST
>> +
>> +static DECLARE_FAULT_ATTR(fail_mmc_request);
>
> I think the fail_attr should be defined for each mmc_host like make_it_fail
> in struct mmc_host and debugfs entries should also be created in a
> subdirectory of mmc host debugfs.
>
> And I know that init_fault_attr_dentries() can only create a
> subdirectory in debugfs root directory.  But I have a patch which
> support for creating it in arbitrary directory.  Could you take a look
> at this? (Note that this patch is based on mmotm and not yet tested)
>
I tested your patch on a Snowball board. I had two active mmc cards
and did various fault injection configurations on the two cards
together with dd. I did only test MMC IO fault injection and not any
of the other fault injection clients.
Tested-by: Per Forlin <per.forlin at linaro.org>

Regards,
Per