Re: [PATCH] mmc: queue: exclude asynchronous transfer for special request

[Konstantin Dorfman <kdorfman@codeaurora.org>]

Hello,

On 12/20/2012 12:27 PM, Seungwon Jeon wrote:
> Unlike normal r/w request, special requests(discard, flush)
> is finished with a one-time issue_fn. Request change to
> mqrq_prev makes unnecessary call.
>
> Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
> ---
>   drivers/mmc/card/queue.c |    8 ++++++++
>   1 files changed, 8 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/mmc/card/queue.c b/drivers/mmc/card/queue.c
> index fadf52e..a71db7a 100644
> --- a/drivers/mmc/card/queue.c
> +++ b/drivers/mmc/card/queue.c
> @@ -58,6 +58,7 @@ static int mmc_queue_thread(void *d)
>   	do {
>   		struct request *req = NULL;
>   		struct mmc_queue_req *tmp;
> +		unsigned int cmd_flags = 0;
>   
>   		spin_lock_irq(q->queue_lock);
>   		set_current_state(TASK_INTERRUPTIBLE);
> @@ -67,12 +68,19 @@ static int mmc_queue_thread(void *d)
>   
>   		if (req || mq->mqrq_prev->req) {
>   			set_current_state(TASK_RUNNING);
> +			cmd_flags = req ? req->cmd_flags : 0;
>   			mq->issue_fn(mq, req);
>   
>   			/*
>   			 * Current request becomes previous request
>   			 * and vice versa.
> +			 * In case of special requests, current request
> +			 * has been finished. Do not remain it to previous
> +			 * request.
>   			 */
> +			if (cmd_flags & REQ_DISCARD || cmd_flags & REQ_FLUSH)
> +				mq->mqrq_cur->req = NULL;
> +
It is better to define control mask, REQ_CONTROL_MASK, which will 
include all control/special requests.
Then, when additional requests will be added, there will be no need to 
change here.

Another option - to clean mq->mqrq_cur->req immediately after executing 
a special request in mmc_blk_issue_rq().
  mq->mqrq_prev->brq.mrq.data = NULL; mq->mqrq_prev->req = NULL; tmp = 
mq->mqrq_prev;