[Lucid] pull-request: mmc: fix all hangs related to mmc/sd card insert/removal during suspend/resume
Stefan Bader
stefan.bader at canonical.com
Fri Sep 3 16:20:13 UTC 2010
Yes, this looks more reasonable to me. I try to give it some additional testing
next week as well.
ACK
On 09/03/2010 06:05 PM, Lee Jones wrote:
> Hi Stefan,
>
> I'm not entirely sure what the repercussions are going to be of changing the semantics of the original code found in 2.6.36. However, I offer this to you as you requested it.
>
> --------------------------------------------------------------------------
>
> The following changes since commit 5470af5fd104192214b496a2736fd26200f4650d:
> Steve Conklin (1):
> UBUNTU: [Config] updateconfigs
>
> are available in the git repository at:
>
> git://kernel.ubuntu.com/lag/ubuntu-lucid.git lp477106
>
> Lee Jones (1):
> mmc: fix all hangs related to mmc/sd card insert/removal during suspend/resume
>
> drivers/mmc/core/core.c | 81 +++++++++++++++++++++++++++++++--------------
> drivers/mmc/core/host.c | 5 +++
> include/linux/mmc/host.h | 3 ++
> 3 files changed, 64 insertions(+), 25 deletions(-)
>
> --------------------------------------------------------------------------
>
> mmc: fix all hangs related to mmc/sd card insert/removal during suspend/resume
>
> Based on a patch-set originally written by Maxim Levitsky.
>
> If you don't use CONFIG_MMC_UNSAFE_RESUME, as soon as you attempt to
> suspend, the card will be removed, therefore this patch doesn't change the
> behavior of this option.
>
> However the removal will be done by pm notifier, which runs while
> userspace is still not frozen and thus can freely use del_gendisk, without
> the risk of deadlock which would happen otherwise.
>
> Card detect workqueue is now disabled while userspace is frozen, Therefore
> if you do use CONFIG_MMC_UNSAFE_RESUME, and remove the card during
> suspend, the removal will be detected as soon as userspace is unfrozen,
> again at the moment it is safe to call del_gendisk.
>
> Tested with and without CONFIG_MMC_UNSAFE_RESUME with suspend and hibernate.
>
> [akpm at linux-foundation.org: clean up function prototype]
> [akpm at linux-foundation.org: fix CONFIG_PM-n linkage, small cleanups]
> [akpm at linux-foundation.org: coding-style fixes]
> Signed-off-by: Maxim Levitsky <maximlevitsky at gmail.com>
> Cc: David Brownell <david-b at pacbell.net>
> Cc: Alan Stern <stern at rowland.harvard.edu>
> Cc: <linux-mmc at vger.kernel.org>
> Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
> Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
>
> [Backported to Ubuntu-2.6.32-25.43 by Lee Jones]
> Signed-off-by: Lee Jones <lee.jones at canonical.com>
>
> BugLink: http://bugs.launchpad.net/bugs/477106
>
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index 30acd52..46f6157 100644 (file)
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -1057,6 +1057,17 @@ void mmc_rescan(struct work_struct *work)
> container_of(work, struct mmc_host, detect.work);
> u32 ocr;
> int err;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&host->lock, flags);
> +
> + if (host->rescan_disable) {
> + spin_unlock_irqrestore(&host->lock, flags);
> + return;
> + }
> +
> + spin_unlock_irqrestore(&host->lock, flags);
> +
>
> mmc_bus_get(host);
>
> @@ -1263,18 +1274,6 @@ int mmc_suspend_host(struct mmc_host *host, pm_message_t state)
> if (host->bus_ops && !host->bus_dead) {
> if (host->bus_ops->suspend)
> err = host->bus_ops->suspend(host);
> - if (err == -ENOSYS || !host->bus_ops->resume) {
> - /*
> - * We simply "remove" the card in this case.
> - * It will be redetected on resume.
> - */
> - if (host->bus_ops->remove)
> - host->bus_ops->remove(host);
> - mmc_claim_host(host);
> - mmc_detach_bus(host);
> - mmc_release_host(host);
> - err = 0;
> - }
> }
> mmc_bus_put(host);
>
> @@ -1304,28 +1303,60 @@ int mmc_resume_host(struct mmc_host *host)
> printk(KERN_WARNING "%s: error %d during resume "
> "(card was removed?)\n",
> mmc_hostname(host), err);
> - if (host->bus_ops->remove)
> - host->bus_ops->remove(host);
> - mmc_claim_host(host);
> - mmc_detach_bus(host);
> - mmc_release_host(host);
> - /* no need to bother upper layers */
> err = 0;
> }
> }
> mmc_bus_put(host);
>
> - /*
> - * We add a slight delay here so that resume can progress
> - * in parallel.
> - */
> - mmc_detect_change(host, 1);
> -
> return err;
> }
> -
> EXPORT_SYMBOL(mmc_resume_host);
>
> +/* Do the card removal on suspend if card is assumed removeable
> + * Do that in pm notifier while userspace isn't yet frozen, so we will be able
> + to sync the card.
> +*/
> +int mmc_pm_notify(struct notifier_block *notify_block,
> + unsigned long mode, void *unused)
> +{
> + struct mmc_host *host = container_of(
> + notify_block, struct mmc_host, pm_notify);
> + unsigned long flags;
> +
> +
> + switch (mode) {
> + case PM_HIBERNATION_PREPARE:
> + case PM_SUSPEND_PREPARE:
> +
> + spin_lock_irqsave(&host->lock, flags);
> + host->rescan_disable = 1;
> + spin_unlock_irqrestore(&host->lock, flags);
> + cancel_delayed_work_sync(&host->detect);
> +
> + if (!host->bus_ops || host->bus_ops->suspend)
> + break;
> +
> + mmc_claim_host(host);
> +
> + if (host->bus_ops->remove)
> + host->bus_ops->remove(host);
> +
> + mmc_detach_bus(host);
> + mmc_release_host(host);
> + break;
> +
> + case PM_POST_SUSPEND:
> + case PM_POST_HIBERNATION:
> +
> + spin_lock_irqsave(&host->lock, flags);
> + host->rescan_disable = 0;
> + spin_unlock_irqrestore(&host->lock, flags);
> + mmc_detect_change(host, 0);
> +
> + }
> +
> + return 0;
> +}
> #endif
>
> static int __init mmc_init(void)
> diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
> index a268d12..0efe631 100644 (file)
> --- a/drivers/mmc/core/host.c
> +++ b/drivers/mmc/core/host.c
> @@ -16,6 +16,8 @@
> #include <linux/idr.h>
> #include <linux/pagemap.h>
> #include <linux/leds.h>
> +#include <linux/slab.h>
> +#include <linux/suspend.h>
>
> #include <linux/mmc/host.h>
>
> @@ -84,6 +86,7 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
> init_waitqueue_head(&host->wq);
> INIT_DELAYED_WORK(&host->detect, mmc_rescan);
> INIT_DELAYED_WORK_DEFERRABLE(&host->disable, mmc_host_deeper_disable);
> + host->pm_notify.notifier_call = mmc_pm_notify;
>
> /*
> * By default, hosts do not support SGIO or large requests.
> @@ -132,6 +135,7 @@ int mmc_add_host(struct mmc_host *host)
> #endif
>
> mmc_start_host(host);
> + register_pm_notifier(&host->pm_notify);
>
> return 0;
> }
> @@ -148,6 +152,7 @@ EXPORT_SYMBOL(mmc_add_host);
> */
> void mmc_remove_host(struct mmc_host *host)
> {
> + unregister_pm_notifier(&host->pm_notify);
> mmc_stop_host(host);
>
> #ifdef CONFIG_DEBUG_FS
> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
> index eaf3636..475ca8a 100644 (file)
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -120,6 +120,7 @@ struct mmc_host {
> unsigned int f_min;
> unsigned int f_max;
> u32 ocr_avail;
> + struct notifier_block pm_notify;
>
> #define MMC_VDD_165_195 0x00000080 /* VDD voltage 1.65 - 1.95 */
> #define MMC_VDD_20_21 0x00000100 /* VDD voltage 2.0 ~ 2.1 */
> @@ -177,6 +178,7 @@ struct mmc_host {
>
> /* Only used with MMC_CAP_DISABLE */
> int enabled; /* host is enabled */
> + int rescan_disable; /* disable card detection */
> int nesting_cnt; /* "enable" nesting count */
> int en_dis_recurs; /* detect recursion */
> unsigned int disable_delay; /* disable delay in msecs */
> @@ -249,6 +251,7 @@ int mmc_card_can_sleep(struct mmc_host *host);
> int mmc_host_enable(struct mmc_host *host);
> int mmc_host_disable(struct mmc_host *host);
> int mmc_host_lazy_disable(struct mmc_host *host);
> +int mmc_pm_notify(struct notifier_block *notify_block, unsigned long, void *);
>
> static inline void mmc_set_disable_delay(struct mmc_host *host,
> unsigned int disable_delay)
>
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