[3/3] PM: runtime: Resume the device earlier in __device_release_driver()
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Message ID 1708806.S9fAqql2gf@kreacher
State New, archived
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Series
  • PM: runtime: Fixes related to device links management
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Commit Message

Rafael J. Wysocki Oct. 21, 2020, 7:14 p.m. UTC
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Since the device is resumed from runtime-suspend in
__device_release_driver() anyway, it is better to do that before
looking for busy managed device links from it to consumers, because
if there are any, device_links_unbind_consumers() will be called
and it will cause the consumer devices' drivers to unbind, so the
consumer devices will be runtime-resumed.  In turn, resuming each
consumer device will cause the supplier to be resumed and when the
runtime PM references from the given consumer to it are dropped, it
may be suspended.  Then, the runtime-resume of the next consumer
will cause the supplier to resume again and so on.

Update the code accordingly.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Fixes: 9ed9895370ae ("driver core: Functional dependencies tracking support")
Cc: All applicable <stable@vger.kernel.org> # All applicable
---
 drivers/base/dd.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

chenxiang (M) Oct. 22, 2020, 1:40 p.m. UTC | #1
Hi Rafael,

在 2020/10/22 3:14, Rafael J. Wysocki 写道:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> Since the device is resumed from runtime-suspend in
> __device_release_driver() anyway, it is better to do that before
> looking for busy managed device links from it to consumers, because
> if there are any, device_links_unbind_consumers() will be called
> and it will cause the consumer devices' drivers to unbind, so the
> consumer devices will be runtime-resumed.  In turn, resuming each
> consumer device will cause the supplier to be resumed and when the
> runtime PM references from the given consumer to it are dropped, it
> may be suspended.  Then, the runtime-resume of the next consumer
> will cause the supplier to resume again and so on.
>
> Update the code accordingly.
>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> Fixes: 9ed9895370ae ("driver core: Functional dependencies tracking support")
> Cc: All applicable <stable@vger.kernel.org> # All applicable
> ---
>   drivers/base/dd.c |    4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
>
> Index: linux-pm/drivers/base/dd.c
> ===================================================================
> --- linux-pm.orig/drivers/base/dd.c
> +++ linux-pm/drivers/base/dd.c
> @@ -1117,6 +1117,8 @@ static void __device_release_driver(stru
>   
>   	drv = dev->driver;
>   	if (drv) {
> +		pm_runtime_get_sync(dev);
> +
>   		while (device_links_busy(dev)) {
>   			__device_driver_unlock(dev, parent);
>   
> @@ -1132,8 +1134,6 @@ static void __device_release_driver(stru

pm_runtime_put_sync() is required to be called if existed from here.

>   				return;
>   		}
>   
> -		pm_runtime_get_sync(dev);
> -
>   		driver_sysfs_remove(dev);
>   
>   		if (dev->bus)
>
>
>
>
> .
>
Rafael J. Wysocki Oct. 22, 2020, 2:16 p.m. UTC | #2
On Thu, Oct 22, 2020 at 3:40 PM chenxiang (M) <chenxiang66@hisilicon.com> wrote:
>
> Hi Rafael,
>
> 在 2020/10/22 3:14, Rafael J. Wysocki 写道:
> > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> >
> > Since the device is resumed from runtime-suspend in
> > __device_release_driver() anyway, it is better to do that before
> > looking for busy managed device links from it to consumers, because
> > if there are any, device_links_unbind_consumers() will be called
> > and it will cause the consumer devices' drivers to unbind, so the
> > consumer devices will be runtime-resumed.  In turn, resuming each
> > consumer device will cause the supplier to be resumed and when the
> > runtime PM references from the given consumer to it are dropped, it
> > may be suspended.  Then, the runtime-resume of the next consumer
> > will cause the supplier to resume again and so on.
> >
> > Update the code accordingly.
> >
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > Fixes: 9ed9895370ae ("driver core: Functional dependencies tracking support")
> > Cc: All applicable <stable@vger.kernel.org> # All applicable
> > ---
> >   drivers/base/dd.c |    4 ++--
> >   1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > Index: linux-pm/drivers/base/dd.c
> > ===================================================================
> > --- linux-pm.orig/drivers/base/dd.c
> > +++ linux-pm/drivers/base/dd.c
> > @@ -1117,6 +1117,8 @@ static void __device_release_driver(stru
> >
> >       drv = dev->driver;
> >       if (drv) {
> > +             pm_runtime_get_sync(dev);
> > +
> >               while (device_links_busy(dev)) {
> >                       __device_driver_unlock(dev, parent);
> >
> > @@ -1132,8 +1134,6 @@ static void __device_release_driver(stru
>
> pm_runtime_put_sync() is required to be called if existed from here.
>
> >                               return;

Right, I overlooked this, thanks!

> >               }
> >
> > -             pm_runtime_get_sync(dev);
> > -
> >               driver_sysfs_remove(dev);
> >
> >               if (dev->bus)

Patch
diff mbox series

Index: linux-pm/drivers/base/dd.c
===================================================================
--- linux-pm.orig/drivers/base/dd.c
+++ linux-pm/drivers/base/dd.c
@@ -1117,6 +1117,8 @@  static void __device_release_driver(stru
 
 	drv = dev->driver;
 	if (drv) {
+		pm_runtime_get_sync(dev);
+
 		while (device_links_busy(dev)) {
 			__device_driver_unlock(dev, parent);
 
@@ -1132,8 +1134,6 @@  static void __device_release_driver(stru
 				return;
 		}
 
-		pm_runtime_get_sync(dev);
-
 		driver_sysfs_remove(dev);
 
 		if (dev->bus)