Patchwork [Maverick] pull-request: mmc: fix all hangs related to mmc/sd card insert/removal during

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Submitter Lee Jones
Date Sept. 2, 2010, 10:19 a.m.
Message ID <4C7F7A1B.5040800@canonical.com>
Download mbox | patch
Permalink /patch/63467/
State Rejected
Delegated to: Leann Ogasawara
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Lee Jones - Sept. 2, 2010, 10:19 a.m.
This patch fixes:

BugLink: http://bugs.launchpad.net/bugs/477106

The following changes since commit 9f02aef9921f0f213a6680768641eb2af6113c3b:
  Leann Ogasawara (1):
        UBUNTU: Start new release

are available in the git repository at:

  git://kernel.ubuntu.com/lag/ubuntu-maverick.git lp477106-mmc-suspend

Maxim Levitsky (1):
      mmc: fix all hangs related to mmc/sd card insert/removal during suspend/resume

 drivers/mmc/core/core.c  |   83 +++++++++++++++++++++++++++++++--------------
 drivers/mmc/core/host.c  |    4 ++
 include/linux/mmc/host.h |    3 ++
 3 files changed, 64 insertions(+), 26 deletions(-)

-------------------------------------------------------------------

From: Maxim Levitsky <maximlevitsky@gmail.com>
Date: Wed, 11 Aug 2010 01:01:41 +0000 (-0700)
Subject: mmc: fix all hangs related to mmc/sd card insert/removal during suspend/resume

mmc: fix all hangs related to mmc/sd card insert/removal during suspend/resume

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.

Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
Andy Whitcroft - Sept. 2, 2010, 1:57 p.m.
On Thu, Sep 02, 2010 at 11:19:07AM +0100, Lee Jones wrote:
> This patch fixes:
> 
> BugLink: http://bugs.launchpad.net/bugs/477106
> 
> The following changes since commit 9f02aef9921f0f213a6680768641eb2af6113c3b:
>   Leann Ogasawara (1):
>         UBUNTU: Start new release
> 
> are available in the git repository at:
> 
>   git://kernel.ubuntu.com/lag/ubuntu-maverick.git lp477106-mmc-suspend
> 
> Maxim Levitsky (1):
>       mmc: fix all hangs related to mmc/sd card insert/removal during suspend/resume
> 
>  drivers/mmc/core/core.c  |   83 +++++++++++++++++++++++++++++++--------------
>  drivers/mmc/core/host.c  |    4 ++
>  include/linux/mmc/host.h |    3 ++
>  3 files changed, 64 insertions(+), 26 deletions(-)
> 
> -------------------------------------------------------------------
> 
> From: Maxim Levitsky <maximlevitsky@gmail.com>
> Date: Wed, 11 Aug 2010 01:01:41 +0000 (-0700)
> Subject: mmc: fix all hangs related to mmc/sd card insert/removal during suspend/resume
> 
> mmc: fix all hangs related to mmc/sd card insert/removal during suspend/resume
> 
> 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.
> 
> Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

From the signed-off-by lines I assume this is an upstream patch from
Linus' tree.  If so you should use the  -x option when cherry picking it
so we retain the upstream identifier.  This is critical when we carry
forward the patch set to Natty.

-apw
> ---
> 
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index b69ce91..83240fa 100644
> --- 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);
>  
> @@ -1274,19 +1285,6 @@ int mmc_suspend_host(struct mmc_host *host)
>  	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);
> -			host->pm_flags = 0;
> -			err = 0;
> -		}
>  	}
>  	mmc_bus_put(host);
>  
> @@ -1318,28 +1316,61 @@ 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);
> +		host->pm_flags = 0;
> +		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 4735390..0efe631 100644
> --- a/drivers/mmc/core/host.c
> +++ b/drivers/mmc/core/host.c
> @@ -17,6 +17,7 @@
>  #include <linux/pagemap.h>
>  #include <linux/leds.h>
>  #include <linux/slab.h>
> +#include <linux/suspend.h>
>  
>  #include <linux/mmc/host.h>
>  
> @@ -85,6 +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.
> @@ -133,6 +135,7 @@ int mmc_add_host(struct mmc_host *host)
>  #endif
>  
>  	mmc_start_host(host);
> +	register_pm_notifier(&host->pm_notify);
>  
>  	return 0;
>  }
> @@ -149,6 +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 f65913c..513ff03 100644
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -124,6 +124,7 @@ 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 */
> @@ -183,6 +184,7 @@ 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 */
> @@ -257,6 +259,7 @@ 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)
> 
> -- 
> kernel-team mailing list
> kernel-team@lists.ubuntu.com
> https://lists.ubuntu.com/mailman/listinfo/kernel-team
Lee Jones - Sept. 2, 2010, 2:15 p.m.
>> Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
>> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
>> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
> 
> From the signed-off-by lines I assume this is an upstream patch from
> Linus' tree.  If so you should use the  -x option when cherry picking it
> so we retain the upstream identifier.  This is critical when we carry
> forward the patch set to Natty.

Sounds reasonable. 

I'll cherry pick it again with the -x option.

Patch

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index b69ce91..83240fa 100644
--- 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);
 
@@ -1274,19 +1285,6 @@  int mmc_suspend_host(struct mmc_host *host)
 	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);
-			host->pm_flags = 0;
-			err = 0;
-		}
 	}
 	mmc_bus_put(host);
 
@@ -1318,28 +1316,61 @@  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);
+		host->pm_flags = 0;
+		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 4735390..0efe631 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -17,6 +17,7 @@ 
 #include <linux/pagemap.h>
 #include <linux/leds.h>
 #include <linux/slab.h>
+#include <linux/suspend.h>
 
 #include <linux/mmc/host.h>
 
@@ -85,6 +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.
@@ -133,6 +135,7 @@  int mmc_add_host(struct mmc_host *host)
 #endif
 
 	mmc_start_host(host);
+	register_pm_notifier(&host->pm_notify);
 
 	return 0;
 }
@@ -149,6 +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 f65913c..513ff03 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -124,6 +124,7 @@  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 */
@@ -183,6 +184,7 @@  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 */
@@ -257,6 +259,7 @@  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)