[PATCH] PM: Prevent waiting forever on asynchronous suspend after abort

[PATCH] PM: Prevent waiting forever on asynchronous suspend after abort

[Mandeep Singh Baines]

__device_suspend() must always send a completion. Otherwise, parent
devices will wait forever.

Commit 1e2ef05b, "PM: Limit race conditions between runtime PM and
system sleep (v2)", introduced a regression by short-circuiting the
complete_all() for certain error cases.

This patch fixes the bug by always signalling a completion.

Addresses http://crosbug.com/31972

Tested by injecting an abort via the following patch:

diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c
index a004db3..e5a6fce 100644
--- a/drivers/usb/core/hcd-pci.c
+++ b/drivers/usb/core/hcd-pci.c
@@ -21,6 +21,7 @@
 #include <linux/pci.h>
 #include <linux/usb.h>
 #include <linux/usb/hcd.h>
+#include <linux/string.h>

 #include <asm/io.h>
 #include <asm/irq.h>
@@ -477,6 +478,8 @@ static int resume_common(struct device *dev, int event)

 static int hcd_pci_suspend(struct device *dev)
 {
+       if (!strcmp("0000:00:1d.3", dev_name(dev)))
+               return -EBUSY;
        return suspend_common(dev, device_may_wakeup(dev));
 }

Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: linux-pm@vger.kernel.org
Cc: stable@kernel.org
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Len Brown <len.brown@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Colin Cross <ccross@android.com>
Cc: Sameer Nanda <snanda@chromium.org>
Cc: Olof Johansson <olofj@chromium.org>
---
 drivers/base/power/main.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index e0fb5b0..9cb845e 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -1031,7 +1031,7 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 	dpm_wait_for_children(dev, async);
 
 	if (async_error)
-		return 0;
+		goto Complete;
 
 	pm_runtime_get_noresume(dev);
 	if (pm_runtime_barrier(dev) && device_may_wakeup(dev))
@@ -1040,7 +1040,7 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 	if (pm_wakeup_pending()) {
 		pm_runtime_put_sync(dev);
 		async_error = -EBUSY;
-		return 0;
+		goto Complete;
 	}
 
 	device_lock(dev);
@@ -1097,6 +1097,8 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 	}
 
 	device_unlock(dev);
+
+ Complete:
 	complete_all(&dev->power.completion);
 
 	if (error) {
-- 
1.7.3.4

Re: [PATCH] PM: Prevent waiting forever on asynchronous suspend after abort

[Alan Stern]

On Tue, 19 Jun 2012, Mandeep Singh Baines wrote:

> __device_suspend() must always send a completion. Otherwise, parent
> devices will wait forever.
> 
> Commit 1e2ef05b, "PM: Limit race conditions between runtime PM and
> system sleep (v2)", introduced a regression by short-circuiting the
> complete_all() for certain error cases.
> 
> This patch fixes the bug by always signalling a completion.
> 
> Addresses http://crosbug.com/31972
> 
> Tested by injecting an abort via the following patch:
> 
> diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c
> index a004db3..e5a6fce 100644
> --- a/drivers/usb/core/hcd-pci.c
> +++ b/drivers/usb/core/hcd-pci.c
> @@ -21,6 +21,7 @@
>  #include <linux/pci.h>
>  #include <linux/usb.h>
>  #include <linux/usb/hcd.h>
> +#include <linux/string.h>
> 
>  #include <asm/io.h>
>  #include <asm/irq.h>
> @@ -477,6 +478,8 @@ static int resume_common(struct device *dev, int event)
> 
>  static int hcd_pci_suspend(struct device *dev)
>  {
> +       if (!strcmp("0000:00:1d.3", dev_name(dev)))
> +               return -EBUSY;
>         return suspend_common(dev, device_may_wakeup(dev));
>  }

When you include one patch in front of another like this, doesn't it 
confuse the automatic tools?  You might end up getting both changes 
include in the final commit.  :-)

>  drivers/base/power/main.c |    6 ++++--
>  1 files changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
> index e0fb5b0..9cb845e 100644
> --- a/drivers/base/power/main.c
> +++ b/drivers/base/power/main.c
> @@ -1031,7 +1031,7 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
>  	dpm_wait_for_children(dev, async);
>  
>  	if (async_error)
> -		return 0;
> +		goto Complete;
>  
>  	pm_runtime_get_noresume(dev);
>  	if (pm_runtime_barrier(dev) && device_may_wakeup(dev))
> @@ -1040,7 +1040,7 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
>  	if (pm_wakeup_pending()) {
>  		pm_runtime_put_sync(dev);
>  		async_error = -EBUSY;
> -		return 0;
> +		goto Complete;
>  	}
>  
>  	device_lock(dev);
> @@ -1097,6 +1097,8 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
>  	}
>  
>  	device_unlock(dev);
> +
> + Complete:
>  	complete_all(&dev->power.completion);
>  
>  	if (error) {

Otherwise this looks right to me.

Acked-by: Alan Stern <stern@rowland.harvard.edu>

Re: [PATCH] PM: Prevent waiting forever on asynchronous suspend after abort

[Greg Kroah-Hartman]

On Wed, Jun 20, 2012 at 10:58:25AM -0400, Alan Stern wrote:
> On Tue, 19 Jun 2012, Mandeep Singh Baines wrote:
> 
> > __device_suspend() must always send a completion. Otherwise, parent
> > devices will wait forever.
> > 
> > Commit 1e2ef05b, "PM: Limit race conditions between runtime PM and
> > system sleep (v2)", introduced a regression by short-circuiting the
> > complete_all() for certain error cases.
> > 
> > This patch fixes the bug by always signalling a completion.
> > 
> > Addresses http://crosbug.com/31972
> > 
> > Tested by injecting an abort via the following patch:
> > 
> > diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c
> > index a004db3..e5a6fce 100644
> > --- a/drivers/usb/core/hcd-pci.c
> > +++ b/drivers/usb/core/hcd-pci.c
> > @@ -21,6 +21,7 @@
> >  #include <linux/pci.h>
> >  #include <linux/usb.h>
> >  #include <linux/usb/hcd.h>
> > +#include <linux/string.h>
> > 
> >  #include <asm/io.h>
> >  #include <asm/irq.h>
> > @@ -477,6 +478,8 @@ static int resume_common(struct device *dev, int event)
> > 
> >  static int hcd_pci_suspend(struct device *dev)
> >  {
> > +       if (!strcmp("0000:00:1d.3", dev_name(dev)))
> > +               return -EBUSY;
> >         return suspend_common(dev, device_may_wakeup(dev));
> >  }
> 
> When you include one patch in front of another like this, doesn't it 
> confuse the automatic tools?  You might end up getting both changes 
> include in the final commit.  :-)

Yeah, that's going to mess with quilt big time, I don't know what git is
going to do with it, it should be interesting to see...

greg k-h

Re: [PATCH] PM: Prevent waiting forever on asynchronous suspend after abort

[Mandeep Baines]

On Wed, Jun 20, 2012 at 7:58 AM, Alan Stern <stern@rowland.harvard.edu> wrote:
> On Tue, 19 Jun 2012, Mandeep Singh Baines wrote:
>
>> __device_suspend() must always send a completion. Otherwise, parent
>> devices will wait forever.
>>
>> Commit 1e2ef05b, "PM: Limit race conditions between runtime PM and
>> system sleep (v2)", introduced a regression by short-circuiting the
>> complete_all() for certain error cases.
>>
>> This patch fixes the bug by always signalling a completion.
>>
>> Addresses http://crosbug.com/31972
>>
>> Tested by injecting an abort via the following patch:
>>
>> diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c
>> index a004db3..e5a6fce 100644
>> --- a/drivers/usb/core/hcd-pci.c
>> +++ b/drivers/usb/core/hcd-pci.c
>> @@ -21,6 +21,7 @@
>>  #include <linux/pci.h>
>>  #include <linux/usb.h>
>>  #include <linux/usb/hcd.h>
>> +#include <linux/string.h>
>>
>>  #include <asm/io.h>
>>  #include <asm/irq.h>
>> @@ -477,6 +478,8 @@ static int resume_common(struct device *dev, int event)
>>
>>  static int hcd_pci_suspend(struct device *dev)
>>  {
>> +       if (!strcmp("0000:00:1d.3", dev_name(dev)))
>> +               return -EBUSY;
>>         return suspend_common(dev, device_may_wakeup(dev));
>>  }
>
> When you include one patch in front of another like this, doesn't it
> confuse the automatic tools?  You might end up getting both changes
> include in the final commit.  :-)
>

Ah. Good point. Removed the test code and re-sent.

>>  drivers/base/power/main.c |    6 ++++--
>>  1 files changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
>> index e0fb5b0..9cb845e 100644
>> --- a/drivers/base/power/main.c
>> +++ b/drivers/base/power/main.c
>> @@ -1031,7 +1031,7 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
>>       dpm_wait_for_children(dev, async);
>>
>>       if (async_error)
>> -             return 0;
>> +             goto Complete;
>>
>>       pm_runtime_get_noresume(dev);
>>       if (pm_runtime_barrier(dev) && device_may_wakeup(dev))
>> @@ -1040,7 +1040,7 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
>>       if (pm_wakeup_pending()) {
>>               pm_runtime_put_sync(dev);
>>               async_error = -EBUSY;
>> -             return 0;
>> +             goto Complete;
>>       }
>>
>>       device_lock(dev);
>> @@ -1097,6 +1097,8 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
>>       }
>>
>>       device_unlock(dev);
>> +
>> + Complete:
>>       complete_all(&dev->power.completion);
>>
>>       if (error) {
>
> Otherwise this looks right to me.
>
> Acked-by: Alan Stern <stern@rowland.harvard.edu>
>

[PATCH] PM: Prevent waiting forever on asynchronous suspend after abort

[mandeep.baines]

From: Mandeep Singh Baines <msb@chromium.org>

__device_suspend() must always send a completion. Otherwise, parent
devices will wait forever.

Commit 1e2ef05b, "PM: Limit race conditions between runtime PM and
system sleep (v2)", introduced a regression by short-circuiting the
complete_all() for certain error cases.

This patch fixes the bug by always signalling a completion.

Addresses http://crosbug.com/31972

Tested by injecting an abort.

Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: linux-pm@vger.kernel.org
Cc: stable@kernel.org
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Len Brown <len.brown@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Colin Cross <ccross@android.com>
Cc: Sameer Nanda <snanda@chromium.org>
Cc: Olof Johansson <olofj@chromium.org>
---
 drivers/base/power/main.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index e0fb5b0..9cb845e 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -1031,7 +1031,7 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 	dpm_wait_for_children(dev, async);
 
 	if (async_error)
-		return 0;
+		goto Complete;
 
 	pm_runtime_get_noresume(dev);
 	if (pm_runtime_barrier(dev) && device_may_wakeup(dev))
@@ -1040,7 +1040,7 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 	if (pm_wakeup_pending()) {
 		pm_runtime_put_sync(dev);
 		async_error = -EBUSY;
-		return 0;
+		goto Complete;
 	}
 
 	device_lock(dev);
@@ -1097,6 +1097,8 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 	}
 
 	device_unlock(dev);
+
+ Complete:
 	complete_all(&dev->power.completion);
 
 	if (error) {
-- 
1.7.3.4

Re: [PATCH] PM: Prevent waiting forever on asynchronous suspend after abort

[Rafael J. Wysocki]

On Wednesday, June 20, 2012, mandeep.baines@gmail.com wrote:
> From: Mandeep Singh Baines <msb@chromium.org>
> 
> __device_suspend() must always send a completion. Otherwise, parent
> devices will wait forever.
> 
> Commit 1e2ef05b, "PM: Limit race conditions between runtime PM and
> system sleep (v2)", introduced a regression by short-circuiting the
> complete_all() for certain error cases.
> 
> This patch fixes the bug by always signalling a completion.
> 
> Addresses http://crosbug.com/31972
> 
> Tested by injecting an abort.
> 
> Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
> Cc: Rafael J. Wysocki <rjw@sisk.pl>
> Cc: linux-pm@vger.kernel.org
> Cc: stable@kernel.org
> Cc: Pavel Machek <pavel@ucw.cz>
> Cc: Len Brown <len.brown@intel.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Kevin Hilman <khilman@ti.com>
> Cc: Alan Stern <stern@rowland.harvard.edu>
> Cc: Colin Cross <ccross@android.com>
> Cc: Sameer Nanda <snanda@chromium.org>
> Cc: Olof Johansson <olofj@chromium.org>

Applied to linux-pm/linux-next, will be pushed to Linus in a couple of days.

Thanks,
Rafael


> ---
>  drivers/base/power/main.c |    6 ++++--
>  1 files changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
> index e0fb5b0..9cb845e 100644
> --- a/drivers/base/power/main.c
> +++ b/drivers/base/power/main.c
> @@ -1031,7 +1031,7 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
>  	dpm_wait_for_children(dev, async);
>  
>  	if (async_error)
> -		return 0;
> +		goto Complete;
>  
>  	pm_runtime_get_noresume(dev);
>  	if (pm_runtime_barrier(dev) && device_may_wakeup(dev))
> @@ -1040,7 +1040,7 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
>  	if (pm_wakeup_pending()) {
>  		pm_runtime_put_sync(dev);
>  		async_error = -EBUSY;
> -		return 0;
> +		goto Complete;
>  	}
>  
>  	device_lock(dev);
> @@ -1097,6 +1097,8 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
>  	}
>  
>  	device_unlock(dev);
> +
> + Complete:
>  	complete_all(&dev->power.completion);
>  
>  	if (error) {
> 

[PATCH] PM: Prevent waiting forever on asynchronous suspend after abort

[Mandeep Singh Baines]

__device_suspend() must always send a completion. Otherwise, parent
devices will wait forever.

Commit 1e2ef05b, "PM: Limit race conditions between runtime PM and
system sleep (v2)", introduced a regression by short-circuiting the
complete_all() for certain error cases.

This patch fixes the bug by always signalling a completion.

Addresses http://crosbug.com/31972

Tested by injecting an abort via the following patch:

diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c
index a004db3..e5a6fce 100644
--- a/drivers/usb/core/hcd-pci.c
+++ b/drivers/usb/core/hcd-pci.c
@@ -21,6 +21,7 @@
 #include <linux/pci.h>
 #include <linux/usb.h>
 #include <linux/usb/hcd.h>
+#include <linux/string.h>

 #include <asm/io.h>
 #include <asm/irq.h>
@@ -477,6 +478,8 @@ static int resume_common(struct device *dev, int event)

 static int hcd_pci_suspend(struct device *dev)
 {
+       if (!strcmp("0000:00:1d.3", dev_name(dev)))
+               return -EBUSY;
        return suspend_common(dev, device_may_wakeup(dev));
 }

Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: linux-pm@vger.kernel.org
Cc: stable@kernel.org
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Len Brown <len.brown@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Colin Cross <ccross@android.com>
Cc: Sameer Nanda <snanda@chromium.org>
Cc: Olof Johansson <olofj@chromium.org>
---
 drivers/base/power/main.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index e0fb5b0..9cb845e 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -1031,7 +1031,7 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 	dpm_wait_for_children(dev, async);
 
 	if (async_error)
-		return 0;
+		goto Complete;
 
 	pm_runtime_get_noresume(dev);
 	if (pm_runtime_barrier(dev) && device_may_wakeup(dev))
@@ -1040,7 +1040,7 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 	if (pm_wakeup_pending()) {
 		pm_runtime_put_sync(dev);
 		async_error = -EBUSY;
-		return 0;
+		goto Complete;
 	}
 
 	device_lock(dev);
@@ -1097,6 +1097,8 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 	}
 
 	device_unlock(dev);
+
+ Complete:
 	complete_all(&dev->power.completion);
 
 	if (error) {
-- 
1.7.3.4