Re: [PATCH] mmc: core: fix the aysync mechanism when card removed

[Jaehoon Chung <jh80.chung@samsung.com>]

Hi Seungwon,

I didn't see your patch "[PATCH 1/2] mmc: core: fix permanent sleep of mmcqd during card removal".
But i found the patch. right..i think it's also same problem.

Your patch is more generic..great.
I will reply to your patch with my acked.

Best Regards,
Jaehoon Chung

On 01/31/2013 07:48 PM, Seungwon Jeon wrote:
> On Thursday, January 31, 2013, Jaehoon Chung wrote:
>> On 01/31/2013 05:42 PM, Subhash Jadavani wrote:
>>> On 1/22/2013 5:48 PM, Jaehoon Chung wrote:
>>>> When card removed, then didn't complete the previously data.
>>>> (It didn't wakeup any interrupt.)
>>>> If card is removed, then we can assume to complete the previously data.
>>>> And wakeup the interrupt for wait_event of data.
>>>>
>>>> This problem is produced when sd-card is removed.(Sd-card is running some operation)
>>>>
>>>> Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
>>>> Signed-off-by: Kyungmin Park <Kyungmin.park@samsung.com>
>>>> ---
>>>>   drivers/mmc/core/core.c |   31 ++++++++++++++++++++-----------
>>>>   1 files changed, 20 insertions(+), 11 deletions(-)
>>>>
>>>> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
>>>> index 8b3a122..bc1d627 100644
>>>> --- a/drivers/mmc/core/core.c
>>>> +++ b/drivers/mmc/core/core.c
>>>> @@ -515,17 +515,26 @@ struct mmc_async_req *mmc_start_req(struct mmc_host *host,
>>>>           mmc_pre_req(host, areq->mrq, !host->areq);
>>>>         if (host->areq) {
>>>> -            err = mmc_wait_for_data_req_done(host, host->areq->mrq,
>>>> -                    areq);
>>>> -            if (err == MMC_BLK_NEW_REQUEST) {
>>>> -                if (error)
>>>> -                    *error = err;
>>>> -                /*
>>>> -                 * The previous request was not completed,
>>>> -                 * nothing to return
>>>> -                 */
>>>> -                return NULL;
>>>> -            }
>>>> +        err = mmc_wait_for_data_req_done(host, host->areq->mrq,
>>>> +                areq);
>>>> +        if (err == MMC_BLK_NEW_REQUEST) {
>>>> +            if (error)
>>>> +                *error = err;
>>>> +            /*
>>>> +             * The previous request was not completed,
>>>> +             * nothing to return
>>>> +             */
>>>> +            return NULL;
>>>> +        } else if (err == MMC_BLK_NOMEDIUM && areq) {
>>>> +            struct mmc_context_info *ctnx = &host->context_info;
>>>> +            /*
>>>> +             * If crad is removed,
>>>> +             * then we didn't wait for data completed.
>>>> +             * Assume that data-recieve done.
>>>> +             */
>>>> +            ctnx->is_done_rcv = true;
>>>> +            wake_up_interruptible(&ctnx->wait);
>>>
>>> Can you please explain more on what exactly we are trying to do here (may be you can list down the
>> call flow)? I am not sure if i understood this correctly. But why would you need to wakeup the thread
>> here? We are here because thread is already woken up. mmc_wait_for_data_req_done() would return only
>> if either the new request is received or the currently running request on controller is completed.
>> This problem is produced when card is removed and running some operation.
>> If card is removed, mmc_wait_for_data_req_done() is returned error, right?
>> But if there was async request and running async operation, then maybe run mmc_start_request() with
>> areq.
>> controller is waiting "_for_req_data_done_" for areq.
>>
>> If request is host->areq.process is running at this time.
>> But if request is areq(prepared request), then mmc_wait_for_data_req_done should be pending.
>> and system is dead-lock.
> I also found this problem with sdcard.
> I think it can be solved easily. Did you see the following patch?
> [PATCH 1/2] mmc: core: fix permanent sleep of mmcqd during card removal
> We may just get the hint from __mmc_start_req function.
> 
> Thanks,
> Seungwon Jeon
>>
>> Best Regards,
>> Jaehoon Chung
>>
>>>
>>> Regards,
>>> Subhash
>>>
>>>> +        }
>>>>           /*
>>>>            * Check BKOPS urgency for each R1 response
>>>>            */
>>>
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