Re: [PATCH V7 06/25] mmc: queue: Introduce queue depth

[Adrian Hunter <adrian.hunter@intel.com>]

On 28/11/16 06:19, Ritesh Harjani wrote:
> 
> 
> On 11/25/2016 3:37 PM, Adrian Hunter wrote:
>> Add a mmc_queue member to record the size of the queue, which currently
>> supports 2 requests on-the-go at a time.
>>
>> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
>> ---
>>  drivers/mmc/card/block.c | 3 +++
>>  drivers/mmc/card/queue.c | 1 +
>>  drivers/mmc/card/queue.h | 1 +
>>  3 files changed, 5 insertions(+)
>>
>> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
>> index f8e51640596e..47835b78872f 100644
>> --- a/drivers/mmc/card/block.c
>> +++ b/drivers/mmc/card/block.c
>> @@ -1439,6 +1439,9 @@ static int mmc_packed_init(struct mmc_queue *mq,
>> struct mmc_card *card)
>>      struct mmc_queue_req *mqrq_prev = &mq->mqrq[1];
>>      int ret = 0;
>>
>> +    /* Queue depth is only ever 2 with packed commands */
>> +    if (mq->qdepth != 2)
>> +        return -EINVAL;
> I think you are referring here that with SWMCDQ, packed commands wont be
> used. Instead of qdepth do you think we should check cmdq_en ?
> Also maybe we shouldn't even call mmc_packed_init if cmdq_en is true?

mmc_packed_init() has gone away but the intention was to make the code
protect itself because the implementation supports only 2 requests.  So,
something like this would be more explicit:

	/* Packed commands implementation depends on qdepth being 2 */
	if (mq->qdepth != 2) {
		WARN_ON(1):
		return -EINVAL;
	}

> 
> 
>>
>>      mqrq_cur->packed = kzalloc(sizeof(struct mmc_packed), GFP_KERNEL);
>>      if (!mqrq_cur->packed) {
>> diff --git a/drivers/mmc/card/queue.c b/drivers/mmc/card/queue.c
>> index cbe92c9cfda1..60fa095adb14 100644
>> --- a/drivers/mmc/card/queue.c
>> +++ b/drivers/mmc/card/queue.c
>> @@ -296,6 +296,7 @@ int mmc_init_queue(struct mmc_queue *mq, struct
>> mmc_card *card,
>>      if (!mq->queue)
>>          return -ENOMEM;
>>
>> +    mq->qdepth = 2;
>>      mq->mqrq_cur = &mq->mqrq[0];
>>      mq->mqrq_prev = &mq->mqrq[1];
>>      mq->queue->queuedata = mq;
>> diff --git a/drivers/mmc/card/queue.h b/drivers/mmc/card/queue.h
>> index 0e8133c626c9..8a0a45e5650d 100644
>> --- a/drivers/mmc/card/queue.h
>> +++ b/drivers/mmc/card/queue.h
>> @@ -64,6 +64,7 @@ struct mmc_queue {
>>      struct mmc_queue_req    mqrq[2];
>>      struct mmc_queue_req    *mqrq_cur;
>>      struct mmc_queue_req    *mqrq_prev;
>> +    int            qdepth;
>>  };
>>
>>  extern int mmc_init_queue(struct mmc_queue *, struct mmc_card *,
>> spinlock_t *,
>>
>