On Thursday, December 20, 2012, Konstantin Dorfman wrote:
> Hello Jeon,
>
>
> 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@xxxxxxxxxxx>
> > ---
> > 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;
> > +
> > mq->mqrq_prev->brq.mrq.data = NULL;
> > mq->mqrq_prev->req = NULL;
> > tmp = mq->mqrq_prev;
> >
> It is better to define control mask, REQ_CONTROL_MASK, which will
> include all control/special requests.
Agree, it's better.
>
> Then, when additional request will be added, there will be no need to
> change here, only update the mask.
>
> Another option - to clean mq->mqrq_cur->req immediately after executing
> a special request in mmc_blk_issue_rq().
Yes, I also approached it with the same idea at the beginning.
But it seems that 'queue.c' has a role of management of two requests,
while 'block.c' just uses these request. It makes sense?
Thanks,
Seungwon Jeon
>
>
> --
> Konstantin Dorfman,
> QUALCOMM ISRAEL, on behalf of Qualcomm Innovation Center,
> Inc. is a member of Code Aurora Forum,
> hosted by The Linux Foundation
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