On 03/02/12 14:16, Ulf Hansson wrote:
> Adrian Hunter wrote:
>> On 03/02/12 11:33, Ulf Hansson wrote:
>>> To prevent I/O as soon as possible at card removal, a new
>>> detect work is re-scheduled without a delay to let a rescan
>>> remove the card device as soon a possible.
>>>
>>> Additionally, MMC_CAP2_DETECT_ON_ERR can now be used to handle
>>> "slowly" removed cards that a scheduled detect work did not
>>> detect as removed. To prevent further I/O requests for these
>>> lingering removed cards, check if card has been removed and then
>>> schedule a detect work to properly remove it.
>>>
>>> Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxxxxxx>
>>> ---
>>>
>>> Changes in v3:
>>> - Check for card is NULL and minor code simplifications.
>>>
>>> Changes in v2:
>>> - Updated according to review comments.
>>> - Merging two patches for this feature into one.
>>>
>>> ---
>>> drivers/mmc/core/core.c | 24 +++++++++++++++++++++---
>>> include/linux/mmc/host.h | 1 +
>>> 2 files changed, 22 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
>>> index bec0bf2..9645e8c 100644
>>> --- a/drivers/mmc/core/core.c
>>> +++ b/drivers/mmc/core/core.c
>>> @@ -2077,18 +2077,36 @@ int _mmc_detect_card_removed(struct mmc_host *host)
>>> int mmc_detect_card_removed(struct mmc_host *host)
>>> {
>>> struct mmc_card *card = host->card;
>>> + int ret;
>>>
>>> WARN_ON(!host->claimed);
>>> +
>>> + if (!card)
>>> + return 1;
>>> +
>>> + ret = mmc_card_removed(card);
>>> /*
>>> * The card will be considered unchanged unless we have been asked to
>>> * detect a change or host requires polling to provide card detection.
>>> */
>>> - if (card && !host->detect_change && !(host->caps & MMC_CAP_NEEDS_POLL))
>>> - return mmc_card_removed(card);
>>> + if (!host->detect_change && !(host->caps & MMC_CAP_NEEDS_POLL) &&
>>> + !(host->caps2 & MMC_CAP2_DETECT_ON_ERR))
>>> + return ret;
>>>
>>> host->detect_change = 0;
>>> + if (!ret) {
>>> + ret = _mmc_detect_card_removed(host);
>>> + if (ret) {
>>
>> Please make this
>>
>> if (ret && (host->caps2 & MMC_CAP2_DETECT_ON_ERR))
>>
>> because if rescan is already running this will needlessly queue
>> another one.
>>
>
> It wont queue another one. It will cancel a work which likely has been
> scheduled to be executed within several ms later. Then it will re-schedule a
> new one without any delay since there is no need to wait, when we already
> know that the card has been removed.
It won't cancel a rescan that is already running (waiting to claim the host
for example) but it will queue another one. Hence the comment.
>
>
>>> + /*
>>> + * Schedule a detect work as soon as possible to let a
>>> + * rescan handle the card removal.
>>> + */
>>> + cancel_delayed_work(&host->detect);
>>> + mmc_detect_change(host, 0);
>>> + }
>>> + }
>>>
>>> - return _mmc_detect_card_removed(host);
>>> + return ret;
>>> }
>>> EXPORT_SYMBOL(mmc_detect_card_removed);
>>>
>>> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
>>> index dd13e05..368a2b9 100644
>>> --- a/include/linux/mmc/host.h
>>> +++ b/include/linux/mmc/host.h
>>> @@ -257,6 +257,7 @@ struct mmc_host {
>>> #define MMC_CAP2_HS200_1_2V_SDR (1 << 6) /* can support */
>>> #define MMC_CAP2_HS200 (MMC_CAP2_HS200_1_8V_SDR | \
>>> MMC_CAP2_HS200_1_2V_SDR)
>>> +#define MMC_CAP2_DETECT_ON_ERR (1 << 7) /* On I/O err check card
>>> removal */
>>>
>>> mmc_pm_flag_t pm_caps; /* supported pm features */
>>> unsigned int power_notify_type;
>>
>>
>
>
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