diff mbox series

[v2] PM: runtime: Update device status before letting suppliers suspend

Message ID 2024466.aZ6alR0V7q@kreacher (mailing list archive)
State Awaiting Upstream
Delegated to: Rafael Wysocki
Headers show
Series [v2] PM: runtime: Update device status before letting suppliers suspend | expand

Commit Message

Rafael J. Wysocki Feb. 25, 2021, 6:23 p.m. UTC
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Because the PM-runtime status of the device is not updated in
__rpm_callback(), attempts to suspend the suppliers of the given
device triggered by rpm_put_suppliers() called by it may fail.

Fix this by making __rpm_callback() update the device's status to
RPM_SUSPENDED before calling rpm_put_suppliers() if the current
status of the device is RPM_SUSPENDING and the callback just invoked
by it has returned 0 (success).

While at it, modify the code in __rpm_callback() to always check
the device's PM-runtime status under its PM lock.

Link: https://lore.kernel.org/linux-pm/CAPDyKFqm06KDw_p8WXsM4dijDbho4bb6T4k50UqqvR1_COsp8g@mail.gmail.com/
Fixes: 21d5c57b3726 ("PM / runtime: Use device links")
Reported-by: elaine.zhang <zhangqing@rock-chips.com>
Diagnosed-by: Ulf Hansson <ulf.hansson@linaro.org> 
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---

v1 -> v2:
   * Initialize the "get" variable to avoid a false-positive warning from
     the compiler.

---
 drivers/base/power/runtime.c |   62 +++++++++++++++++++++++++------------------
 1 file changed, 37 insertions(+), 25 deletions(-)

Comments

Elaine Zhang Feb. 26, 2021, 1:11 a.m. UTC | #1
Hi, Rafael:

The patch V2 test works well.

Tested-by: Elaine Zhang <zhangiqng@rock-chips.com>

在 2021/2/26 上午2:23, Rafael J. Wysocki 写道:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> Because the PM-runtime status of the device is not updated in
> __rpm_callback(), attempts to suspend the suppliers of the given
> device triggered by rpm_put_suppliers() called by it may fail.
>
> Fix this by making __rpm_callback() update the device's status to
> RPM_SUSPENDED before calling rpm_put_suppliers() if the current
> status of the device is RPM_SUSPENDING and the callback just invoked
> by it has returned 0 (success).
>
> While at it, modify the code in __rpm_callback() to always check
> the device's PM-runtime status under its PM lock.
>
> Link: https://lore.kernel.org/linux-pm/CAPDyKFqm06KDw_p8WXsM4dijDbho4bb6T4k50UqqvR1_COsp8g@mail.gmail.com/
> Fixes: 21d5c57b3726 ("PM / runtime: Use device links")
> Reported-by: elaine.zhang <zhangqing@rock-chips.com>
> Diagnosed-by: Ulf Hansson <ulf.hansson@linaro.org>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
>
> v1 -> v2:
>     * Initialize the "get" variable to avoid a false-positive warning from
>       the compiler.
>
> ---
>   drivers/base/power/runtime.c |   62 +++++++++++++++++++++++++------------------
>   1 file changed, 37 insertions(+), 25 deletions(-)
>
> Index: linux-pm/drivers/base/power/runtime.c
> ===================================================================
> --- linux-pm.orig/drivers/base/power/runtime.c
> +++ linux-pm/drivers/base/power/runtime.c
> @@ -325,22 +325,22 @@ static void rpm_put_suppliers(struct dev
>   static int __rpm_callback(int (*cb)(struct device *), struct device *dev)
>   	__releases(&dev->power.lock) __acquires(&dev->power.lock)
>   {
> -	int retval, idx;
>   	bool use_links = dev->power.links_count > 0;
> +	bool get = false;
> +	int retval, idx;
> +	bool put;
>   
>   	if (dev->power.irq_safe) {
>   		spin_unlock(&dev->power.lock);
> +	} else if (!use_links) {
> +		spin_unlock_irq(&dev->power.lock);
>   	} else {
> +		get = dev->power.runtime_status == RPM_RESUMING;
> +
>   		spin_unlock_irq(&dev->power.lock);
>   
> -		/*
> -		 * Resume suppliers if necessary.
> -		 *
> -		 * The device's runtime PM status cannot change until this
> -		 * routine returns, so it is safe to read the status outside of
> -		 * the lock.
> -		 */
> -		if (use_links && dev->power.runtime_status == RPM_RESUMING) {
> +		/* Resume suppliers if necessary. */
> +		if (get) {
>   			idx = device_links_read_lock();
>   
>   			retval = rpm_get_suppliers(dev);
> @@ -355,24 +355,36 @@ static int __rpm_callback(int (*cb)(stru
>   
>   	if (dev->power.irq_safe) {
>   		spin_lock(&dev->power.lock);
> -	} else {
> -		/*
> -		 * If the device is suspending and the callback has returned
> -		 * success, drop the usage counters of the suppliers that have
> -		 * been reference counted on its resume.
> -		 *
> -		 * Do that if resume fails too.
> -		 */
> -		if (use_links
> -		    && ((dev->power.runtime_status == RPM_SUSPENDING && !retval)
> -		    || (dev->power.runtime_status == RPM_RESUMING && retval))) {
> -			idx = device_links_read_lock();
> +		return retval;
> +	}
>   
> - fail:
> -			rpm_put_suppliers(dev);
> +	spin_lock_irq(&dev->power.lock);
>   
> -			device_links_read_unlock(idx);
> -		}
> +	if (!use_links)
> +		return retval;
> +
> +	/*
> +	 * If the device is suspending and the callback has returned success,
> +	 * drop the usage counters of the suppliers that have been reference
> +	 * counted on its resume.
> +	 *
> +	 * Do that if the resume fails too.
> +	 */
> +	put = dev->power.runtime_status == RPM_SUSPENDING && !retval;
> +	if (put)
> +		__update_runtime_status(dev, RPM_SUSPENDED);
> +	else
> +		put = get && retval;
> +
> +	if (put) {
> +		spin_unlock_irq(&dev->power.lock);
> +
> +		idx = device_links_read_lock();
> +
> +fail:
> +		rpm_put_suppliers(dev);
> +
> +		device_links_read_unlock(idx);
>   
>   		spin_lock_irq(&dev->power.lock);
>   	}
>
>
>
>
>
>
Ulf Hansson Feb. 26, 2021, 9:56 a.m. UTC | #2
On Thu, 25 Feb 2021 at 19:23, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
>
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> Because the PM-runtime status of the device is not updated in
> __rpm_callback(), attempts to suspend the suppliers of the given
> device triggered by rpm_put_suppliers() called by it may fail.
>
> Fix this by making __rpm_callback() update the device's status to
> RPM_SUSPENDED before calling rpm_put_suppliers() if the current
> status of the device is RPM_SUSPENDING and the callback just invoked
> by it has returned 0 (success).
>
> While at it, modify the code in __rpm_callback() to always check
> the device's PM-runtime status under its PM lock.
>
> Link: https://lore.kernel.org/linux-pm/CAPDyKFqm06KDw_p8WXsM4dijDbho4bb6T4k50UqqvR1_COsp8g@mail.gmail.com/
> Fixes: 21d5c57b3726 ("PM / runtime: Use device links")
> Reported-by: elaine.zhang <zhangqing@rock-chips.com>
> Diagnosed-by: Ulf Hansson <ulf.hansson@linaro.org>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

Kind regards
Uffe

> ---
>
> v1 -> v2:
>    * Initialize the "get" variable to avoid a false-positive warning from
>      the compiler.
>
> ---
>  drivers/base/power/runtime.c |   62 +++++++++++++++++++++++++------------------
>  1 file changed, 37 insertions(+), 25 deletions(-)
>
> Index: linux-pm/drivers/base/power/runtime.c
> ===================================================================
> --- linux-pm.orig/drivers/base/power/runtime.c
> +++ linux-pm/drivers/base/power/runtime.c
> @@ -325,22 +325,22 @@ static void rpm_put_suppliers(struct dev
>  static int __rpm_callback(int (*cb)(struct device *), struct device *dev)
>         __releases(&dev->power.lock) __acquires(&dev->power.lock)
>  {
> -       int retval, idx;
>         bool use_links = dev->power.links_count > 0;
> +       bool get = false;
> +       int retval, idx;
> +       bool put;
>
>         if (dev->power.irq_safe) {
>                 spin_unlock(&dev->power.lock);
> +       } else if (!use_links) {
> +               spin_unlock_irq(&dev->power.lock);
>         } else {
> +               get = dev->power.runtime_status == RPM_RESUMING;
> +
>                 spin_unlock_irq(&dev->power.lock);
>
> -               /*
> -                * Resume suppliers if necessary.
> -                *
> -                * The device's runtime PM status cannot change until this
> -                * routine returns, so it is safe to read the status outside of
> -                * the lock.
> -                */
> -               if (use_links && dev->power.runtime_status == RPM_RESUMING) {
> +               /* Resume suppliers if necessary. */
> +               if (get) {
>                         idx = device_links_read_lock();
>
>                         retval = rpm_get_suppliers(dev);
> @@ -355,24 +355,36 @@ static int __rpm_callback(int (*cb)(stru
>
>         if (dev->power.irq_safe) {
>                 spin_lock(&dev->power.lock);
> -       } else {
> -               /*
> -                * If the device is suspending and the callback has returned
> -                * success, drop the usage counters of the suppliers that have
> -                * been reference counted on its resume.
> -                *
> -                * Do that if resume fails too.
> -                */
> -               if (use_links
> -                   && ((dev->power.runtime_status == RPM_SUSPENDING && !retval)
> -                   || (dev->power.runtime_status == RPM_RESUMING && retval))) {
> -                       idx = device_links_read_lock();
> +               return retval;
> +       }
>
> - fail:
> -                       rpm_put_suppliers(dev);
> +       spin_lock_irq(&dev->power.lock);
>
> -                       device_links_read_unlock(idx);
> -               }
> +       if (!use_links)
> +               return retval;
> +
> +       /*
> +        * If the device is suspending and the callback has returned success,
> +        * drop the usage counters of the suppliers that have been reference
> +        * counted on its resume.
> +        *
> +        * Do that if the resume fails too.
> +        */
> +       put = dev->power.runtime_status == RPM_SUSPENDING && !retval;
> +       if (put)
> +               __update_runtime_status(dev, RPM_SUSPENDED);
> +       else
> +               put = get && retval;
> +
> +       if (put) {
> +               spin_unlock_irq(&dev->power.lock);
> +
> +               idx = device_links_read_lock();
> +
> +fail:
> +               rpm_put_suppliers(dev);
> +
> +               device_links_read_unlock(idx);
>
>                 spin_lock_irq(&dev->power.lock);
>         }
>
>
>
diff mbox series

Patch

Index: linux-pm/drivers/base/power/runtime.c
===================================================================
--- linux-pm.orig/drivers/base/power/runtime.c
+++ linux-pm/drivers/base/power/runtime.c
@@ -325,22 +325,22 @@  static void rpm_put_suppliers(struct dev
 static int __rpm_callback(int (*cb)(struct device *), struct device *dev)
 	__releases(&dev->power.lock) __acquires(&dev->power.lock)
 {
-	int retval, idx;
 	bool use_links = dev->power.links_count > 0;
+	bool get = false;
+	int retval, idx;
+	bool put;
 
 	if (dev->power.irq_safe) {
 		spin_unlock(&dev->power.lock);
+	} else if (!use_links) {
+		spin_unlock_irq(&dev->power.lock);
 	} else {
+		get = dev->power.runtime_status == RPM_RESUMING;
+
 		spin_unlock_irq(&dev->power.lock);
 
-		/*
-		 * Resume suppliers if necessary.
-		 *
-		 * The device's runtime PM status cannot change until this
-		 * routine returns, so it is safe to read the status outside of
-		 * the lock.
-		 */
-		if (use_links && dev->power.runtime_status == RPM_RESUMING) {
+		/* Resume suppliers if necessary. */
+		if (get) {
 			idx = device_links_read_lock();
 
 			retval = rpm_get_suppliers(dev);
@@ -355,24 +355,36 @@  static int __rpm_callback(int (*cb)(stru
 
 	if (dev->power.irq_safe) {
 		spin_lock(&dev->power.lock);
-	} else {
-		/*
-		 * If the device is suspending and the callback has returned
-		 * success, drop the usage counters of the suppliers that have
-		 * been reference counted on its resume.
-		 *
-		 * Do that if resume fails too.
-		 */
-		if (use_links
-		    && ((dev->power.runtime_status == RPM_SUSPENDING && !retval)
-		    || (dev->power.runtime_status == RPM_RESUMING && retval))) {
-			idx = device_links_read_lock();
+		return retval;
+	}
 
- fail:
-			rpm_put_suppliers(dev);
+	spin_lock_irq(&dev->power.lock);
 
-			device_links_read_unlock(idx);
-		}
+	if (!use_links)
+		return retval;
+
+	/*
+	 * If the device is suspending and the callback has returned success,
+	 * drop the usage counters of the suppliers that have been reference
+	 * counted on its resume.
+	 *
+	 * Do that if the resume fails too.
+	 */
+	put = dev->power.runtime_status == RPM_SUSPENDING && !retval;
+	if (put)
+		__update_runtime_status(dev, RPM_SUSPENDED);
+	else
+		put = get && retval;
+
+	if (put) {
+		spin_unlock_irq(&dev->power.lock);
+
+		idx = device_links_read_lock();
+
+fail:
+		rpm_put_suppliers(dev);
+
+		device_links_read_unlock(idx);
 
 		spin_lock_irq(&dev->power.lock);
 	}