>> > @@ -1291,10 +1657,42 @@ static int mmc_blk_issue_rw_rq(struct
>> mmc_queue
>> *mq, struct request *rqc)
>> > * A block was successfully transferred.
>> > */
>> > mmc_blk_reset_success(md, type);
>> > - spin_lock_irq(&md->lock);
>> > - ret = __blk_end_request(req, 0,
>> > +
>> > + if (mq_rq->packed_cmd != MMC_PACKED_NONE) {
>> > + int idx = mq_rq->packed_fail_idx, i = 0;
>> > + ret = 0;
>> > + while (!list_empty(&mq_rq->packed_list)) {
>> > + prq = list_entry_rq(
>> > + mq_rq->packed_list.next);
>> > + if (idx == i) {
>> > + /* retry from error index */
>> > + mq_rq->packed_num -= idx;
>> > + mq_rq->req = prq;
>> > + ret = 1;
>> > + break;
>> > + }
>> > + list_del_init(&prq->queuelist);
>> > + spin_lock_irq(&md->lock);
>> > + __blk_end_request(prq, 0,
>> > + blk_rq_bytes(prq));
>> > + spin_unlock_irq(&md->lock);
>> > + i++;
>> > + }
>> > + if (mq_rq->packed_num == MMC_PACKED_N_SINGLE) {
>> > + prq = list_entry_rq(
>> > + mq_rq->packed_list.next);
>> You already get the prq inside the while. There is no need to do it
>> again.
> Right, but if while loop isn't taken, then prq can be used uninitialized.
> Though that case wouldn't happen actually, we don't want to see the
> compiling error.
The loop must be taken since we are inside the case of packed commands so
the list can't be empty.
If the compiler complained, you can set prq to be the first request before
entering the loop instead of setting it again in the if that follows the
loop. It will probably be more understood.
If you decide to leave it as is, I would also add the following to the if:
+ mq_rq->req = prq;
+ ret = 1;
Otherwise it seems like there could be a bug in cases where the loop is
not taken (since prq is the only one that is set) and the code is less
understood.
Thanks,
Maya Erez
Consultant for Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum
Maya Erez <[email protected]> wrote:
> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On Behalf Of
> [email protected]
> Sent: Thursday, May 03, 2012 3:35 AM
> To: Seungwon Jeon
> Cc: [email protected]; [email protected]; 'Chris Ball'; [email protected]
> Subject: RE: [PATCH v5 2/2] mmc: core: Support packed command for eMMC4.5 device
>
> >> > @@ -1291,10 +1657,42 @@ static int mmc_blk_issue_rw_rq(struct
> >> mmc_queue
> >> *mq, struct request *rqc)
> >> > * A block was successfully transferred.
> >> > */
> >> > mmc_blk_reset_success(md, type);
> >> > - spin_lock_irq(&md->lock);
> >> > - ret = __blk_end_request(req, 0,
> >> > +
> >> > + if (mq_rq->packed_cmd != MMC_PACKED_NONE) {
> >> > + int idx = mq_rq->packed_fail_idx, i = 0;
> >> > + ret = 0;
> >> > + while (!list_empty(&mq_rq->packed_list)) {
> >> > + prq = list_entry_rq(
> >> > + mq_rq->packed_list.next);
> >> > + if (idx == i) {
> >> > + /* retry from error index */
> >> > + mq_rq->packed_num -= idx;
> >> > + mq_rq->req = prq;
> >> > + ret = 1;
> >> > + break;
> >> > + }
> >> > + list_del_init(&prq->queuelist);
> >> > + spin_lock_irq(&md->lock);
> >> > + __blk_end_request(prq, 0,
> >> > + blk_rq_bytes(prq));
> >> > + spin_unlock_irq(&md->lock);
> >> > + i++;
> >> > + }
> >> > + if (mq_rq->packed_num == MMC_PACKED_N_SINGLE) {
> >> > + prq = list_entry_rq(
> >> > + mq_rq->packed_list.next);
> >> You already get the prq inside the while. There is no need to do it
> >> again.
> > Right, but if while loop isn't taken, then prq can be used uninitialized.
> > Though that case wouldn't happen actually, we don't want to see the
> > compiling error.
>
> The loop must be taken since we are inside the case of packed commands so
> the list can't be empty.
>
> If the compiler complained, you can set prq to be the first request before
> entering the loop instead of setting it again in the if that follows the
> loop. It will probably be more understood.
> If you decide to leave it as is, I would also add the following to the if:
> + mq_rq->req = prq;
> + ret = 1;
> Otherwise it seems like there could be a bug in cases where the loop is
> not taken (since prq is the only one that is set) and the code is less
> understood.
I'll clarify this as you concern.
Thank you for your review.
Best regards,
Seungwon Jeon.
>
> Thanks,
> Maya Erez
> Consultant for Qualcomm Innovation Center, Inc.
> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum
>
>
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