Re: [PATCH] mmc: core: Clean up after mmc_pre_req if card was removed

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

On 03/03/2012 12:29 AM, Per Förlin wrote:

> On 03/02/2012 09:51 AM, Ulf HANSSON wrote:
>> Hi Jaehoon,
>>
>> I did not know this. Which host driver are you using? I would very much 
>> appreciate of you could debug and share some result.
>>
>> Thanks!
>>
>> BR
>> Ulf Hansson
>>
>> On 03/02/2012 09:28 AM, Jaehoon Chung wrote:
>>> Hi Ulf.
>>>
>>> I tested with this patch.
>>> But in my environment, this patch didn't work fine before.
>>> 1) When remove/insert, didn't entered the suspend.
>>> 2) When removed during something write,
>>> [   50.755067] FAT-fs (mmcblk1p1): Directory bread(block 8254) failed
>>> [   50.761235] FAT-fs (mmcblk1p1): Directory bread(block 8255) failed
>>> then at next-time, didn't detect sd-card.
>>>
>>> Did you know this?
>>> If you want more information, i will debug, and share the result.
>>>
>>> Best Regards,
>>> Jaehoon Chung
>>>
>>> On 03/02/2012 12:44 AM, Ulf Hansson wrote:
>>>
>>>> Make sure mmc_start_req cancel the prepared job, if the request
>>>> was prevented to be started due to the card has been removed.
>>>>
>>>> This bug was introduced in commit:
>>>> mmc: allow upper layers to know immediately if card has been removed
>>>>
>>>> Signed-off-by: Ulf Hansson<ulf.hansson@stericsson.com>
>>>> ---
>>>>   drivers/mmc/core/core.c |   35 +++++++++++++++--------------------
>>>>   1 files changed, 15 insertions(+), 20 deletions(-)
>>>>
>>>> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
>>>> index 0b317f0..9e562ab 100644
>>>> --- a/drivers/mmc/core/core.c
>>>> +++ b/drivers/mmc/core/core.c
>>>> @@ -249,16 +249,17 @@ static void mmc_wait_done(struct mmc_request *mrq)
>>>>   	complete(&mrq->completion);
>>>>   }
>>>>
>>>> -static void __mmc_start_req(struct mmc_host *host, struct mmc_request *mrq)
>>>> +static int __mmc_start_req(struct mmc_host *host, struct mmc_request *mrq)
>>>>   {
>>>>   	init_completion(&mrq->completion);
>>>>   	mrq->done = mmc_wait_done;
>>>>   	if (mmc_card_removed(host->card)) {
>>>>   		mrq->cmd->error = -ENOMEDIUM;
>>>>   		complete(&mrq->completion);
>>>> -		return;
>>>> +		return -ENOMEDIUM;
>>>>   	}
>>>>   	mmc_start_request(host, mrq);
>>>> +	return 0;
>>>>   }
>>>>
>>>>   static void mmc_wait_for_req_done(struct mmc_host *host,
>>>> @@ -342,6 +343,7 @@ struct mmc_async_req *mmc_start_req(struct mmc_host *host,
>>>>   				    struct mmc_async_req *areq, int *error)
>>>>   {
>>>>   	int err = 0;
>>>> +	int start_err = 0;
>>>>   	struct mmc_async_req *data = host->areq;
>>>>
>>>>   	/* Prepare a new request */
>>>> @@ -351,30 +353,23 @@ struct mmc_async_req *mmc_start_req(struct mmc_host *host,
>>>>   	if (host->areq) {
>>>>   		mmc_wait_for_req_done(host, host->areq->mrq);
>>>>   		err = host->areq->err_check(host->card, host->areq);
>>>> -		if (err) {
>>>> -			/* post process the completed failed request */
>>>> -			mmc_post_req(host, host->areq->mrq, 0);
>>>> -			if (areq)
>>>> -				/*
>>>> -				 * Cancel the new prepared request, because
>>>> -				 * it can't run until the failed
>>>> -				 * request has been properly handled.
>>>> -				 */
>>>> -				mmc_post_req(host, areq->mrq, -EINVAL);
>>>> -
>>>> -			host->areq = NULL;
>>>> -			goto out;
>>>> -		}
>>>>   	}
>>>>
>>>> -	if (areq)
>>>> -		__mmc_start_req(host, areq->mrq);
>>>> +	if (!err&&  areq)
>>>> +		start_err = __mmc_start_req(host, areq->mrq);
>>>>
>>>>   	if (host->areq)
>>>>   		mmc_post_req(host, host->areq->mrq, 0);
>>>>
>>>> -	host->areq = areq;
>>>> - out:
>>>> +	if (err || start_err) {
>>>> +		if (areq)
>>>> +			/* The prepared request was not started, cancel it. */
>>>> +			mmc_post_req(host, areq->mrq, -EINVAL);
>>>> +		host->areq = NULL;
> There seems to be an issue when setting host->areq=NULL when __mmc_start_req fails. host->areq == NULL indicates there are no ongoing transfers.
> host->areq is used in block.c to check if there are pending requests. 
> 
> This seem to work:
> ...
> if (err || start_err) {
> 	if (areq)
> 		/* The prepared request was not started, cancel it. */
> 		mmc_post_req(host, areq->mrq, -EINVAL);
> }
> 
> if (err)
> 	host->areq = NULL;
> else
> 	host->areq = areq;
> ...
> 
> This issue will be addressed in version 2. How to resolve it is not decided yet. 

It seems to work fine. But i didn't test yet.

Best Regards,
Jaehoon Chung

> 
> Feel free to comment,
> Per
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