| Message ID | 4C811CBA.2050407@canonical.com |
|---|---|
| State | Accepted |
| Headers | show |
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@linux-foundation.org: clean up function prototype] > [akpm@linux-foundation.org: fix CONFIG_PM-n linkage, small cleanups] > [akpm@linux-foundation.org: coding-style fixes] > Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com> > Cc: David Brownell <david-b@pacbell.net> > Cc: Alan Stern <stern@rowland.harvard.edu> > Cc: <linux-mmc@vger.kernel.org> > Signed-off-by: Andrew Morton <akpm@linux-foundation.org> > Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> > > [Backported to Ubuntu-2.6.32-25.43 by Lee Jones] > Signed-off-by: Lee Jones <lee.jones@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) >
On 09/03/2010 09:05 AM, 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@linux-foundation.org: clean up function prototype] > [akpm@linux-foundation.org: fix CONFIG_PM-n linkage, small cleanups] > [akpm@linux-foundation.org: coding-style fixes] > Signed-off-by: Maxim Levitsky<maximlevitsky@gmail.com> > Cc: David Brownell<david-b@pacbell.net> > Cc: Alan Stern<stern@rowland.harvard.edu> > Cc:<linux-mmc@vger.kernel.org> > Signed-off-by: Andrew Morton<akpm@linux-foundation.org> > Signed-off-by: Linus Torvalds<torvalds@linux-foundation.org> > > [Backported to Ubuntu-2.6.32-25.43 by Lee Jones] > Signed-off-by: Lee Jones<lee.jones@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) > Acked-by: Brad Figg <brad.figg@canonical.com> The patch looks good to me as well. My suggestion is to get the bug description in the standard SRU request format. Note, we don't require the patch to first be upstream, we just prefer that in most cases. We will still process any patch on a case by case basis for inclusion into one of the stable releases. Look at: https://wiki.ubuntu.com/KernelTeam/StableHandbook https://bugs.launchpad.net/ubuntu/+source/linux/+bug/620755 (an example) Brad
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)
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@linux-foundation.org: clean up function prototype] [akpm@linux-foundation.org: fix CONFIG_PM-n linkage, small cleanups] [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com> Cc: David Brownell <david-b@pacbell.net> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: <linux-mmc@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> [Backported to Ubuntu-2.6.32-25.43 by Lee Jones] Signed-off-by: Lee Jones <lee.jones@canonical.com> BugLink: http://bugs.launchpad.net/bugs/477106