Re: [PATCH V5] mmc:core: Avoid useless detecting task when card is busy

[Zhang Haijun <b42677@freescale.com>]

Thanks Ulf.

Regards

Haijun.

于 2013/9/25 16:31, Ulf Hansson 写道:
> On 25 September 2013 09:27, Haijun Zhang <Haijun.Zhang@freescale.com> wrote:
>> When card is in cpu polling mode to detect card present. Card detecting
>> task will be scheduled about once every second. When card is busy in large
>> file transfer, detecting task will be hang and call trace will be prompt.
>> When handling the request, CMD13 is always followed by every command when
>> it was complete. So assume that card is present to avoid this duplicate
>> detecting. Only polling card when card is free to reduce conflict with
>> data transfer.
>>
>> <7>mmc0: req done (CMD13): 0: 00000e00 00000000 00000000 00000000
>> INFO: task kworker/u:1:12 blocked for more than 120 seconds.
>> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
>> kworker/u:1     D 00000000     0    12      2 0x00000000
>> Call Trace:
>> [ee06dd50] [44042028] 0x44042028
>> (unreliable)
>> [ee06de10] [c0007a0c] __switch_to+0xa0/0xf0
>> [ee06de30] [c04dd50c] __schedule+0x1f8/0x4a4
>>
>> [ee06dea0] [c04dd898] schedule+0x30/0xbc
>>
>> [ee06deb0] [c03816a4] __mmc_claim_host+0x98/0x19c
>>
>> [ee06df00] [c0385f88] mmc_sd_detect+0x38/0xc0
>>
>> [ee06df10] [c0382b0c] mmc_rescan+0x294/0x2e0
>> [ee06df40] [c00661cc] process_one_work+0x140/0x3e0
>>
>> [ee06df70] [c0066bf8] worker_thread+0x18c/0x36c
>> [ee06dfb0] [c006bf10] kthread+0x7c/0x80
>>
>> [ee06dff0] [c000de58] kernel_thread+0x4c/0x68
>> <7>sdhci [sdhci_irq()]: *** mmc0 got interrupt: 0x00000001
>>
>> Signed-off-by: Haijun Zhang <haijun.zhang@freescale.com>
> Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
>
>> ---
>>  drivers/mmc/card/block.c | 28 ++++++++++++++++++++++++++--
>>  drivers/mmc/core/core.c  |  5 +++++
>>  2 files changed, 31 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
>> index 1a3163f..988f16b 100644
>> --- a/drivers/mmc/card/block.c
>> +++ b/drivers/mmc/card/block.c
>> @@ -1960,9 +1960,20 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
>>         struct mmc_host *host = card->host;
>>         unsigned long flags;
>>
>> -       if (req && !mq->mqrq_prev->req)
>> +       if (req && !mq->mqrq_prev->req) {
>> +               /*
>> +                * When we are here, card polling task will be blocked.
>> +                * So disable it to avoid this useless schedule.
>> +                */
>> +               if (host->caps & MMC_CAP_NEEDS_POLL) {
>> +                       spin_lock_irqsave(&host->lock, flags);
>> +                       host->rescan_disable = 1;
>> +                       spin_unlock_irqrestore(&host->lock, flags);
>> +               }
>> +
>>                 /* claim host only for the first request */
>>                 mmc_get_card(card);
>> +       }
>>
>>         ret = mmc_blk_part_switch(card, md);
>>         if (ret) {
>> @@ -1999,7 +2010,7 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
>>
>>  out:
>>         if ((!req && !(mq->flags & MMC_QUEUE_NEW_REQUEST)) ||
>> -            (req && (req->cmd_flags & MMC_REQ_SPECIAL_MASK)))
>> +                       (req && (req->cmd_flags & MMC_REQ_SPECIAL_MASK))) {
>>                 /*
>>                  * Release host when there are no more requests
>>                  * and after special request(discard, flush) is done.
>> @@ -2007,6 +2018,19 @@ out:
>>                  * the 'mmc_blk_issue_rq' with 'mqrq_prev->req'.
>>                  */
>>                 mmc_put_card(card);
>> +
>> +               /*
>> +                * Detecting card status immediately in case card being
>> +                * removed just after the request is complete.
>> +                */
>> +               if (host->caps & MMC_CAP_NEEDS_POLL) {
>> +                       spin_lock_irqsave(&host->lock, flags);
>> +                       host->rescan_disable = 0;
>> +                       spin_unlock_irqrestore(&host->lock, flags);
>> +                       mmc_detect_change(host, 0);
>> +               }
>> +       }
>> +
>>         return ret;
>>  }
>>
>> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
>> index bf18b6b..9ab7020 100644
>> --- a/drivers/mmc/core/core.c
>> +++ b/drivers/mmc/core/core.c
>> @@ -2400,6 +2400,7 @@ int mmc_detect_card_removed(struct mmc_host *host)
>>  {
>>         struct mmc_card *card = host->card;
>>         int ret;
>> +       unsigned long flags;
>>
>>         WARN_ON(!host->claimed);
>>
>> @@ -2422,6 +2423,10 @@ int mmc_detect_card_removed(struct mmc_host *host)
>>                          * Schedule a detect work as soon as possible to let a
>>                          * rescan handle the card removal.
>>                          */
>> +                       spin_lock_irqsave(&host->lock, flags);
>> +                       host->rescan_disable = 0;
>> +                       spin_unlock_irqrestore(&host->lock, flags);
>> +
>>                         cancel_delayed_work(&host->detect);
>>                         mmc_detect_change(host, 0);
>>                 }
>> --
>> 1.8.0
>>
>>
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-- 
Thanks & Regards
Haijun.