| Message ID | 1396995583-5475-1-git-send-email-markus.mayer@linaro.org |
|---|---|
| State | New |
| Headers | show |
On 9 April 2014 00:19, Markus Mayer <markus.mayer@linaro.org> wrote: > This change removes the callback from atomic context which it doesn't > need to be in, and puts it in line with the debounced rescan. > > This code is based on these e-mail threads with Christian Daudt: > > https://lkml.org/lkml/2013/8/19/539 > https://lkml.org/lkml/2014/3/19/79 > > Signed-off-by: Markus Mayer <markus.mayer@linaro.org> > --- > drivers/mmc/core/core.c | 5 +++++ > drivers/mmc/core/slot-gpio.c | 4 +--- > include/linux/mmc/host.h | 2 ++ > 3 files changed, 8 insertions(+), 3 deletions(-) > > diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c > index 098374b..ff7fd2e 100644 > --- a/drivers/mmc/core/core.c > +++ b/drivers/mmc/core/core.c > @@ -2421,6 +2421,11 @@ void mmc_rescan(struct work_struct *work) > container_of(work, struct mmc_host, detect.work); > int i; > > + if (host->trigger_card_event && host->ops->card_event) { > + host->ops->card_event(host); > + host->trigger_card_event = false; > + } > + So this might be a stupid question. :-) Could you elaborate on why the host->ops->card_event then is needed at all. Why can't host drivers use host->ops->get_cd to perform the actions they need? The reason for bringing this up, is because this patch moves the invokes of the these callbacks quite close to each other. Earlier they were more separated. Kind regards Ulf Hansson > if (host->rescan_disable) > return; > > diff --git a/drivers/mmc/core/slot-gpio.c b/drivers/mmc/core/slot-gpio.c > index 46596b71..4029c85 100644 > --- a/drivers/mmc/core/slot-gpio.c > +++ b/drivers/mmc/core/slot-gpio.c > @@ -29,9 +29,7 @@ static irqreturn_t mmc_gpio_cd_irqt(int irq, void *dev_id) > /* Schedule a card detection after a debounce timeout */ > struct mmc_host *host = dev_id; > > - if (host->ops->card_event) > - host->ops->card_event(host); > - > + host->trigger_card_event = true; > mmc_detect_change(host, msecs_to_jiffies(200)); > > return IRQ_HANDLED; > diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h > index 99f5709..63b983b 100644 > --- a/include/linux/mmc/host.h > +++ b/include/linux/mmc/host.h > @@ -322,6 +322,8 @@ struct mmc_host { > int rescan_disable; /* disable card detection */ > int rescan_entered; /* used with nonremovable devices */ > > + bool trigger_card_event; /* card_event necessary */ > + > struct mmc_card *card; /* device attached to this host */ > > wait_queue_head_t wq; > -- > 1.7.9.5 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
On 9 April 2014 01:56, Ulf Hansson <ulf.hansson@linaro.org> wrote: >> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c >> index 098374b..ff7fd2e 100644 >> --- a/drivers/mmc/core/core.c >> +++ b/drivers/mmc/core/core.c >> @@ -2421,6 +2421,11 @@ void mmc_rescan(struct work_struct *work) >> container_of(work, struct mmc_host, detect.work); >> int i; >> >> + if (host->trigger_card_event && host->ops->card_event) { >> + host->ops->card_event(host); >> + host->trigger_card_event = false; >> + } >> + > > So this might be a stupid question. :-) > > Could you elaborate on why the host->ops->card_event then is needed at > all. Why can't host drivers use host->ops->get_cd to perform the > actions they need? > > The reason for bringing this up, is because this patch moves the > invokes of the these callbacks quite close to each other. Earlier they > were more separated. Thanks for the question. I looked at the code and I don't think host->ops->get_cd would work in my case. I proposed this change based on behaviour exhibited by sdhci-bcm-kona.c (mutex sleeps in the IRQ handler cause "scheduling while atomic" errors). The idea of this patch is to move the card event processing (which does the actual card detection) out of the interrupt handler, so the mutex in my callback can be used without problems. https://git.linaro.org/landing-teams/working/broadcom/kernel.git/blob/refs/heads/review/mmc-card-event:/drivers/mmc/host/sdhci-bcm-kona.c#l160 An earlier proposal to fix this issue was to simply replace the mutex with a spinlock in sdhci-bcm-kona.c, but that was not seen as good solution. (https://lkml.org/lkml/2014/3/5/527) Based on your question, I looked through the code some more. From what I can tell, SDHCI hosts have their host->ops->get_cd set to sdhci_get_cd() in sdhci.c (specifically by sdhci_add_host()). So, get_cd is not available to me to customize. Maybe we need a different solution from what I proposed above, but I don't think get_cd will do the trick. I can see how moving card_event and get_cd closer together, like I have done, can be a reason for concern. On the flip-side, de-coupling card_event from IRQ processing seems to be beneficial. What do you think? Regards, -Markus -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 9 April 2014 00:19, Markus Mayer <markus.mayer@linaro.org> wrote: > This change removes the callback from atomic context which it doesn't > need to be in, and puts it in line with the debounced rescan. > > This code is based on these e-mail threads with Christian Daudt: > > https://lkml.org/lkml/2013/8/19/539 > https://lkml.org/lkml/2014/3/19/79 > > Signed-off-by: Markus Mayer <markus.mayer@linaro.org> Acked-by: Ulf Hansson <ulf.hansson@linaro.org> > --- > drivers/mmc/core/core.c | 5 +++++ > drivers/mmc/core/slot-gpio.c | 4 +--- > include/linux/mmc/host.h | 2 ++ > 3 files changed, 8 insertions(+), 3 deletions(-) > > diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c > index 098374b..ff7fd2e 100644 > --- a/drivers/mmc/core/core.c > +++ b/drivers/mmc/core/core.c > @@ -2421,6 +2421,11 @@ void mmc_rescan(struct work_struct *work) > container_of(work, struct mmc_host, detect.work); > int i; > > + if (host->trigger_card_event && host->ops->card_event) { > + host->ops->card_event(host); > + host->trigger_card_event = false; > + } > + > if (host->rescan_disable) > return; > > diff --git a/drivers/mmc/core/slot-gpio.c b/drivers/mmc/core/slot-gpio.c > index 46596b71..4029c85 100644 > --- a/drivers/mmc/core/slot-gpio.c > +++ b/drivers/mmc/core/slot-gpio.c > @@ -29,9 +29,7 @@ static irqreturn_t mmc_gpio_cd_irqt(int irq, void *dev_id) > /* Schedule a card detection after a debounce timeout */ > struct mmc_host *host = dev_id; > > - if (host->ops->card_event) > - host->ops->card_event(host); > - > + host->trigger_card_event = true; > mmc_detect_change(host, msecs_to_jiffies(200)); > > return IRQ_HANDLED; > diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h > index 99f5709..63b983b 100644 > --- a/include/linux/mmc/host.h > +++ b/include/linux/mmc/host.h > @@ -322,6 +322,8 @@ struct mmc_host { > int rescan_disable; /* disable card detection */ > int rescan_entered; /* used with nonremovable devices */ > > + bool trigger_card_event; /* card_event necessary */ > + > struct mmc_card *card; /* device attached to this host */ > > wait_queue_head_t wq; > -- > 1.7.9.5 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index 098374b..ff7fd2e 100644 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -2421,6 +2421,11 @@ void mmc_rescan(struct work_struct *work) container_of(work, struct mmc_host, detect.work); int i; + if (host->trigger_card_event && host->ops->card_event) { + host->ops->card_event(host); + host->trigger_card_event = false; + } + if (host->rescan_disable) return; diff --git a/drivers/mmc/core/slot-gpio.c b/drivers/mmc/core/slot-gpio.c index 46596b71..4029c85 100644 --- a/drivers/mmc/core/slot-gpio.c +++ b/drivers/mmc/core/slot-gpio.c @@ -29,9 +29,7 @@ static irqreturn_t mmc_gpio_cd_irqt(int irq, void *dev_id) /* Schedule a card detection after a debounce timeout */ struct mmc_host *host = dev_id; - if (host->ops->card_event) - host->ops->card_event(host); - + host->trigger_card_event = true; mmc_detect_change(host, msecs_to_jiffies(200)); return IRQ_HANDLED; diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h index 99f5709..63b983b 100644 --- a/include/linux/mmc/host.h +++ b/include/linux/mmc/host.h @@ -322,6 +322,8 @@ struct mmc_host { int rescan_disable; /* disable card detection */ int rescan_entered; /* used with nonremovable devices */ + bool trigger_card_event; /* card_event necessary */ + struct mmc_card *card; /* device attached to this host */ wait_queue_head_t wq;
This change removes the callback from atomic context which it doesn't need to be in, and puts it in line with the debounced rescan. This code is based on these e-mail threads with Christian Daudt: https://lkml.org/lkml/2013/8/19/539 https://lkml.org/lkml/2014/3/19/79 Signed-off-by: Markus Mayer <markus.mayer@linaro.org> --- drivers/mmc/core/core.c | 5 +++++ drivers/mmc/core/slot-gpio.c | 4 +--- include/linux/mmc/host.h | 2 ++ 3 files changed, 8 insertions(+), 3 deletions(-)