[25/25] media: i2c: ccs-core: fix pm_runtime_get_sync() usage count
diff mbox series

Message ID 83ec24acb15f17e2ce589575c2f5eb7bdd1daf28.1620207353.git.mchehab+huawei@kernel.org
State New, archived
Headers show
Series
  • Fix some PM runtime issues at the media subsystem
Related show

Commit Message

Mauro Carvalho Chehab May 5, 2021, 9:42 a.m. UTC
The pm_runtime_get_sync() internally increments the
dev->power.usage_count without decrementing it, even on errors.

There is a bug at ccs_pm_get_init(): when this function returns
an error, the stream is not started, and RPM usage_count
should not be incremented. However, if the calls to
v4l2_ctrl_handler_setup() return errors, it will be kept
incremented.

At ccs_suspend() the best is to replace it by the new
pm_runtime_resume_and_get(), introduced by:
commit dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter")
in order to properly decrement the usage counter automatically,
in the case of errors.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
---
 drivers/media/i2c/ccs/ccs-core.c | 39 ++++++++++++++++++++------------
 1 file changed, 24 insertions(+), 15 deletions(-)

Comments

Sakari Ailus May 5, 2021, 10:34 a.m. UTC | #1
Hi Mauro,

Thanks for the patch.

On Wed, May 05, 2021 at 11:42:15AM +0200, Mauro Carvalho Chehab wrote:
> The pm_runtime_get_sync() internally increments the
> dev->power.usage_count without decrementing it, even on errors.
> 
> There is a bug at ccs_pm_get_init(): when this function returns
> an error, the stream is not started, and RPM usage_count
> should not be incremented. However, if the calls to
> v4l2_ctrl_handler_setup() return errors, it will be kept
> incremented.
> 
> At ccs_suspend() the best is to replace it by the new
> pm_runtime_resume_and_get(), introduced by:
> commit dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter")
> in order to properly decrement the usage counter automatically,
> in the case of errors.
> 
> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Could you add Fixes: line and Cc: stable?

The patch that breaks this is 96e3a6b92f23a .

It would be better to fix the bug first so the patch to the stable trees
doesn't need special handling.

> ---
>  drivers/media/i2c/ccs/ccs-core.c | 39 ++++++++++++++++++++------------
>  1 file changed, 24 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/media/i2c/ccs/ccs-core.c b/drivers/media/i2c/ccs/ccs-core.c
> index b05f409014b2..04c3ab9e37b4 100644
> --- a/drivers/media/i2c/ccs/ccs-core.c
> +++ b/drivers/media/i2c/ccs/ccs-core.c
> @@ -1880,21 +1880,33 @@ static int ccs_pm_get_init(struct ccs_sensor *sensor)
>  	struct i2c_client *client = v4l2_get_subdevdata(&sensor->src->sd);
>  	int rval;
>  
> +	/*
> +	 * It can't use pm_runtime_resume_and_get() here, as the driver
> +	 * relies at the returned value to detect if the device was already
> +	 * active or not.
> +	 */
>  	rval = pm_runtime_get_sync(&client->dev);
> -	if (rval < 0) {
> -		pm_runtime_put_noidle(&client->dev);
> +	if (rval < 0)
> +		goto error;
>  
> -		return rval;
> -	} else if (!rval) {
> -		rval = v4l2_ctrl_handler_setup(&sensor->pixel_array->
> -					       ctrl_handler);
> -		if (rval)
> -			return rval;
> +	/* Device was already active, so don't set controls */
> +	if (rval == 1)
> +		return 0;
>  
> -		return v4l2_ctrl_handler_setup(&sensor->src->ctrl_handler);
> -	}
> +	/* Restore V4L2 controls to the suspended device */
> +	rval = v4l2_ctrl_handler_setup(&sensor->pixel_array->ctrl_handler);
> +	if (rval)
> +		goto error;
>  
> +	rval = v4l2_ctrl_handler_setup(&sensor->src->ctrl_handler);
> +	if (rval)
> +		goto error;
> +
> +	/* Keep PM runtime usage_count incremented on success */
>  	return 0;
> +error:
> +	pm_runtime_put_noidle(&client->dev);

This needs to be pm_runtime_put() as the device has been successfully.

> +	return rval;
>  }
>  
>  static int ccs_set_stream(struct v4l2_subdev *subdev, int enable)
> @@ -3089,12 +3101,9 @@ static int __maybe_unused ccs_suspend(struct device *dev)
>  	bool streaming = sensor->streaming;
>  	int rval;
>  
> -	rval = pm_runtime_get_sync(dev);
> -	if (rval < 0) {
> -		pm_runtime_put_noidle(dev);
> -
> +	rval = pm_runtime_resume_and_get(dev);
> +	if (rval < 0)
>  		return rval;
> -	}
>  
>  	if (sensor->streaming)
>  		ccs_stop_streaming(sensor);
Mauro Carvalho Chehab May 5, 2021, 10:57 a.m. UTC | #2
Em Wed, 5 May 2021 13:34:09 +0300
Sakari Ailus <sakari.ailus@linux.intel.com> escreveu:

> Hi Mauro,
> 
> Thanks for the patch.
> 
> On Wed, May 05, 2021 at 11:42:15AM +0200, Mauro Carvalho Chehab wrote:
> > The pm_runtime_get_sync() internally increments the
> > dev->power.usage_count without decrementing it, even on errors.
> > 
> > There is a bug at ccs_pm_get_init(): when this function returns
> > an error, the stream is not started, and RPM usage_count
> > should not be incremented. However, if the calls to
> > v4l2_ctrl_handler_setup() return errors, it will be kept
> > incremented.
> > 
> > At ccs_suspend() the best is to replace it by the new
> > pm_runtime_resume_and_get(), introduced by:
> > commit dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter")
> > in order to properly decrement the usage counter automatically,
> > in the case of errors.
> > 
> > Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>  
> 
> Could you add Fixes: line and Cc: stable?

Sure. See the fixes one enclosed.

> The patch that breaks this is 96e3a6b92f23a .
> 
> It would be better to fix the bug first so the patch to the stable trees
> doesn't need special handling.
> 
> > ---
> >  drivers/media/i2c/ccs/ccs-core.c | 39 ++++++++++++++++++++------------
> >  1 file changed, 24 insertions(+), 15 deletions(-)
> > 
> > diff --git a/drivers/media/i2c/ccs/ccs-core.c b/drivers/media/i2c/ccs/ccs-core.c
> > index b05f409014b2..04c3ab9e37b4 100644
> > --- a/drivers/media/i2c/ccs/ccs-core.c
> > +++ b/drivers/media/i2c/ccs/ccs-core.c
> > @@ -1880,21 +1880,33 @@ static int ccs_pm_get_init(struct ccs_sensor *sensor)
> >  	struct i2c_client *client = v4l2_get_subdevdata(&sensor->src->sd);
> >  	int rval;
> >  
> > +	/*
> > +	 * It can't use pm_runtime_resume_and_get() here, as the driver
> > +	 * relies at the returned value to detect if the device was already
> > +	 * active or not.
> > +	 */
> >  	rval = pm_runtime_get_sync(&client->dev);
> > -	if (rval < 0) {
> > -		pm_runtime_put_noidle(&client->dev);
> > +	if (rval < 0)
> > +		goto error;
> >  
> > -		return rval;
> > -	} else if (!rval) {
> > -		rval = v4l2_ctrl_handler_setup(&sensor->pixel_array->
> > -					       ctrl_handler);
> > -		if (rval)
> > -			return rval;
> > +	/* Device was already active, so don't set controls */
> > +	if (rval == 1)
> > +		return 0;
> >  
> > -		return v4l2_ctrl_handler_setup(&sensor->src->ctrl_handler);
> > -	}
> > +	/* Restore V4L2 controls to the suspended device */
> > +	rval = v4l2_ctrl_handler_setup(&sensor->pixel_array->ctrl_handler);
> > +	if (rval)
> > +		goto error;
> >  
> > +	rval = v4l2_ctrl_handler_setup(&sensor->src->ctrl_handler);
> > +	if (rval)
> > +		goto error;
> > +
> > +	/* Keep PM runtime usage_count incremented on success */
> >  	return 0;
> > +error:
> > +	pm_runtime_put_noidle(&client->dev);  
> 
> This needs to be pm_runtime_put() as the device has been successfully.

Ok.

> 
> > +	return rval;
> >  }
> >  
> >  static int ccs_set_stream(struct v4l2_subdev *subdev, int enable)
> > @@ -3089,12 +3101,9 @@ static int __maybe_unused ccs_suspend(struct device *dev)
> >  	bool streaming = sensor->streaming;
> >  	int rval;
> >  
> > -	rval = pm_runtime_get_sync(dev);
> > -	if (rval < 0) {
> > -		pm_runtime_put_noidle(dev);
> > -
> > +	rval = pm_runtime_resume_and_get(dev);
> > +	if (rval < 0)
> >  		return rval;
> > -	}
> >  
> >  	if (sensor->streaming)
> >  		ccs_stop_streaming(sensor);  
> 

Thanks,
Mauro

---

[PATCH] media: i2c: ccs-core: fix pm_runtime_get_sync() usage count

The pm_runtime_get_sync() internally increments the
dev->power.usage_count without decrementing it, even on errors.

There is a bug at ccs_pm_get_init(): when this function returns
an error, the stream is not started, and RPM usage_count
should not be incremented. However, if the calls to
v4l2_ctrl_handler_setup() return errors, it will be kept
incremented.

At ccs_suspend() the best is to replace it by the new
pm_runtime_resume_and_get(), introduced by:
commit dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter")
in order to properly decrement the usage counter automatically,
in the case of errors.

Fixes: 96e3a6b92f23 ("media: smiapp: Avoid maintaining power state information")
Cc: stable@vger.kernel.org
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

diff --git a/drivers/media/i2c/ccs/ccs-core.c b/drivers/media/i2c/ccs/ccs-core.c
index b05f409014b2..5ea471fefa3a 100644
--- a/drivers/media/i2c/ccs/ccs-core.c
+++ b/drivers/media/i2c/ccs/ccs-core.c
@@ -1880,21 +1880,33 @@ static int ccs_pm_get_init(struct ccs_sensor *sensor)
 	struct i2c_client *client = v4l2_get_subdevdata(&sensor->src->sd);
 	int rval;
 
+	/*
+	 * It can't use pm_runtime_resume_and_get() here, as the driver
+	 * relies at the returned value to detect if the device was already
+	 * active or not.
+	 */
 	rval = pm_runtime_get_sync(&client->dev);
-	if (rval < 0) {
-		pm_runtime_put_noidle(&client->dev);
+	if (rval < 0)
+		goto error;
 
-		return rval;
-	} else if (!rval) {
-		rval = v4l2_ctrl_handler_setup(&sensor->pixel_array->
-					       ctrl_handler);
-		if (rval)
-			return rval;
+	/* Device was already active, so don't set controls */
+	if (rval == 1)
+		return 0;
 
-		return v4l2_ctrl_handler_setup(&sensor->src->ctrl_handler);
-	}
+	/* Restore V4L2 controls to the suspended device */
+	rval = v4l2_ctrl_handler_setup(&sensor->pixel_array->ctrl_handler);
+	if (rval)
+		goto error;
 
+	rval = v4l2_ctrl_handler_setup(&sensor->src->ctrl_handler);
+	if (rval)
+		goto error;
+
+	/* Keep PM runtime usage_count incremented on success */
 	return 0;
+error:
+	pm_runtime_put(&client->dev);
+	return rval;
 }
 
 static int ccs_set_stream(struct v4l2_subdev *subdev, int enable)
Mauro Carvalho Chehab May 5, 2021, 10:58 a.m. UTC | #3
Em Wed, 5 May 2021 12:57:00 +0200
Mauro Carvalho Chehab <mchehab+huawei@kernel.org> escreveu:

> Em Wed, 5 May 2021 13:34:09 +0300
> Sakari Ailus <sakari.ailus@linux.intel.com> escreveu:
> 
> > Hi Mauro,
> > 
> > Thanks for the patch.
> > 
> > On Wed, May 05, 2021 at 11:42:15AM +0200, Mauro Carvalho Chehab wrote:
> > > The pm_runtime_get_sync() internally increments the
> > > dev->power.usage_count without decrementing it, even on errors.
> > > 
> > > There is a bug at ccs_pm_get_init(): when this function returns
> > > an error, the stream is not started, and RPM usage_count
> > > should not be incremented. However, if the calls to
> > > v4l2_ctrl_handler_setup() return errors, it will be kept
> > > incremented.
> > > 
> > > At ccs_suspend() the best is to replace it by the new
> > > pm_runtime_resume_and_get(), introduced by:
> > > commit dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter")
> > > in order to properly decrement the usage counter automatically,
> > > in the case of errors.
> > > 
> > > Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>  
> > 
> > Could you add Fixes: line and Cc: stable?
> 
> Sure. See the fixes one enclosed.
> 
> > The patch that breaks this is 96e3a6b92f23a .
> > 
> > It would be better to fix the bug first so the patch to the stable trees
> > doesn't need special handling.
> > 
> > > ---
> > >  drivers/media/i2c/ccs/ccs-core.c | 39 ++++++++++++++++++++------------
> > >  1 file changed, 24 insertions(+), 15 deletions(-)
> > > 
> > > diff --git a/drivers/media/i2c/ccs/ccs-core.c b/drivers/media/i2c/ccs/ccs-core.c
> > > index b05f409014b2..04c3ab9e37b4 100644
> > > --- a/drivers/media/i2c/ccs/ccs-core.c
> > > +++ b/drivers/media/i2c/ccs/ccs-core.c
> > > @@ -1880,21 +1880,33 @@ static int ccs_pm_get_init(struct ccs_sensor *sensor)
> > >  	struct i2c_client *client = v4l2_get_subdevdata(&sensor->src->sd);
> > >  	int rval;
> > >  
> > > +	/*
> > > +	 * It can't use pm_runtime_resume_and_get() here, as the driver
> > > +	 * relies at the returned value to detect if the device was already
> > > +	 * active or not.
> > > +	 */
> > >  	rval = pm_runtime_get_sync(&client->dev);
> > > -	if (rval < 0) {
> > > -		pm_runtime_put_noidle(&client->dev);
> > > +	if (rval < 0)
> > > +		goto error;
> > >  
> > > -		return rval;
> > > -	} else if (!rval) {
> > > -		rval = v4l2_ctrl_handler_setup(&sensor->pixel_array->
> > > -					       ctrl_handler);
> > > -		if (rval)
> > > -			return rval;
> > > +	/* Device was already active, so don't set controls */
> > > +	if (rval == 1)
> > > +		return 0;
> > >  
> > > -		return v4l2_ctrl_handler_setup(&sensor->src->ctrl_handler);
> > > -	}
> > > +	/* Restore V4L2 controls to the suspended device */
> > > +	rval = v4l2_ctrl_handler_setup(&sensor->pixel_array->ctrl_handler);
> > > +	if (rval)
> > > +		goto error;
> > >  
> > > +	rval = v4l2_ctrl_handler_setup(&sensor->src->ctrl_handler);
> > > +	if (rval)
> > > +		goto error;
> > > +
> > > +	/* Keep PM runtime usage_count incremented on success */
> > >  	return 0;
> > > +error:
> > > +	pm_runtime_put_noidle(&client->dev);  
> > 
> > This needs to be pm_runtime_put() as the device has been successfully.
> 
> Ok.
> 
> > 
> > > +	return rval;
> > >  }
> > >  
> > >  static int ccs_set_stream(struct v4l2_subdev *subdev, int enable)
> > > @@ -3089,12 +3101,9 @@ static int __maybe_unused ccs_suspend(struct device *dev)
> > >  	bool streaming = sensor->streaming;
> > >  	int rval;
> > >  
> > > -	rval = pm_runtime_get_sync(dev);
> > > -	if (rval < 0) {
> > > -		pm_runtime_put_noidle(dev);
> > > -
> > > +	rval = pm_runtime_resume_and_get(dev);
> > > +	if (rval < 0)
> > >  		return rval;
> > > -	}
> > >  
> > >  	if (sensor->streaming)
> > >  		ccs_stop_streaming(sensor);  
> > 
> 
> Thanks,
> Mauro
> 
> ---
> 
> [PATCH] media: i2c: ccs-core: fix pm_runtime_get_sync() usage count
> 
> The pm_runtime_get_sync() internally increments the
> dev->power.usage_count without decrementing it, even on errors.
> 
> There is a bug at ccs_pm_get_init(): when this function returns
> an error, the stream is not started, and RPM usage_count
> should not be incremented. However, if the calls to
> v4l2_ctrl_handler_setup() return errors, it will be kept
> incremented.
> 
> At ccs_suspend() the best is to replace it by the new
> pm_runtime_resume_and_get(), introduced by:
> commit dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter")
> in order to properly decrement the usage counter automatically,
> in the case of errors.
> 
> Fixes: 96e3a6b92f23 ("media: smiapp: Avoid maintaining power state information")
> Cc: stable@vger.kernel.org
> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
> 
> diff --git a/drivers/media/i2c/ccs/ccs-core.c b/drivers/media/i2c/ccs/ccs-core.c
> index b05f409014b2..5ea471fefa3a 100644
> --- a/drivers/media/i2c/ccs/ccs-core.c
> +++ b/drivers/media/i2c/ccs/ccs-core.c
> @@ -1880,21 +1880,33 @@ static int ccs_pm_get_init(struct ccs_sensor *sensor)
>  	struct i2c_client *client = v4l2_get_subdevdata(&sensor->src->sd);
>  	int rval;
>  
> +	/*
> +	 * It can't use pm_runtime_resume_and_get() here, as the driver
> +	 * relies at the returned value to detect if the device was already
> +	 * active or not.
> +	 */
>  	rval = pm_runtime_get_sync(&client->dev);
> -	if (rval < 0) {
> -		pm_runtime_put_noidle(&client->dev);
> +	if (rval < 0)
> +		goto error;
>  
> -		return rval;
> -	} else if (!rval) {
> -		rval = v4l2_ctrl_handler_setup(&sensor->pixel_array->
> -					       ctrl_handler);
> -		if (rval)
> -			return rval;
> +	/* Device was already active, so don't set controls */
> +	if (rval == 1)
> +		return 0;
>  
> -		return v4l2_ctrl_handler_setup(&sensor->src->ctrl_handler);
> -	}
> +	/* Restore V4L2 controls to the suspended device */

In time: I'll fold this at the patch:

diff --git a/drivers/media/i2c/ccs/ccs-core.c b/drivers/media/i2c/ccs/ccs-core.c
index 5ea471fefa3a..4a848ac2d2cd 100644
--- a/drivers/media/i2c/ccs/ccs-core.c
+++ b/drivers/media/i2c/ccs/ccs-core.c
@@ -1896 +1896 @@ static int ccs_pm_get_init(struct ccs_sensor *sensor)
-       /* Restore V4L2 controls to the suspended device */
+       /* Restore V4L2 controls to the previously suspended device */

Regards,
Mauro
Sakari Ailus May 5, 2021, 11:02 a.m. UTC | #4
Hi Mauro,

On Wed, May 05, 2021 at 12:57:00PM +0200, Mauro Carvalho Chehab wrote:
> Em Wed, 5 May 2021 13:34:09 +0300
> Sakari Ailus <sakari.ailus@linux.intel.com> escreveu:
> 
> > Hi Mauro,
> > 
> > Thanks for the patch.
> > 
> > On Wed, May 05, 2021 at 11:42:15AM +0200, Mauro Carvalho Chehab wrote:
> > > The pm_runtime_get_sync() internally increments the
> > > dev->power.usage_count without decrementing it, even on errors.
> > > 
> > > There is a bug at ccs_pm_get_init(): when this function returns
> > > an error, the stream is not started, and RPM usage_count
> > > should not be incremented. However, if the calls to
> > > v4l2_ctrl_handler_setup() return errors, it will be kept
> > > incremented.
> > > 
> > > At ccs_suspend() the best is to replace it by the new
> > > pm_runtime_resume_and_get(), introduced by:
> > > commit dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter")
> > > in order to properly decrement the usage counter automatically,
> > > in the case of errors.
> > > 
> > > Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>  
> > 
> > Could you add Fixes: line and Cc: stable?
> 
> Sure. See the fixes one enclosed.
> 
> > The patch that breaks this is 96e3a6b92f23a .
> > 
> > It would be better to fix the bug first so the patch to the stable trees
> > doesn't need special handling.

Please ignore this comment.

> > 
> > > ---
> > >  drivers/media/i2c/ccs/ccs-core.c | 39 ++++++++++++++++++++------------
> > >  1 file changed, 24 insertions(+), 15 deletions(-)
> > > 
> > > diff --git a/drivers/media/i2c/ccs/ccs-core.c b/drivers/media/i2c/ccs/ccs-core.c
> > > index b05f409014b2..04c3ab9e37b4 100644
> > > --- a/drivers/media/i2c/ccs/ccs-core.c
> > > +++ b/drivers/media/i2c/ccs/ccs-core.c
> > > @@ -1880,21 +1880,33 @@ static int ccs_pm_get_init(struct ccs_sensor *sensor)
> > >  	struct i2c_client *client = v4l2_get_subdevdata(&sensor->src->sd);
> > >  	int rval;
> > >  
> > > +	/*
> > > +	 * It can't use pm_runtime_resume_and_get() here, as the driver
> > > +	 * relies at the returned value to detect if the device was already
> > > +	 * active or not.
> > > +	 */
> > >  	rval = pm_runtime_get_sync(&client->dev);
> > > -	if (rval < 0) {
> > > -		pm_runtime_put_noidle(&client->dev);
> > > +	if (rval < 0)
> > > +		goto error;
> > >  
> > > -		return rval;
> > > -	} else if (!rval) {
> > > -		rval = v4l2_ctrl_handler_setup(&sensor->pixel_array->
> > > -					       ctrl_handler);
> > > -		if (rval)
> > > -			return rval;
> > > +	/* Device was already active, so don't set controls */
> > > +	if (rval == 1)
> > > +		return 0;
> > >  
> > > -		return v4l2_ctrl_handler_setup(&sensor->src->ctrl_handler);
> > > -	}
> > > +	/* Restore V4L2 controls to the suspended device */
> > > +	rval = v4l2_ctrl_handler_setup(&sensor->pixel_array->ctrl_handler);
> > > +	if (rval)
> > > +		goto error;
> > >  
> > > +	rval = v4l2_ctrl_handler_setup(&sensor->src->ctrl_handler);
> > > +	if (rval)
> > > +		goto error;
> > > +
> > > +	/* Keep PM runtime usage_count incremented on success */
> > >  	return 0;
> > > +error:
> > > +	pm_runtime_put_noidle(&client->dev);  
> > 
> > This needs to be pm_runtime_put() as the device has been successfully.
> 
> Ok.
> 
> > 
> > > +	return rval;
> > >  }
> > >  
> > >  static int ccs_set_stream(struct v4l2_subdev *subdev, int enable)
> > > @@ -3089,12 +3101,9 @@ static int __maybe_unused ccs_suspend(struct device *dev)
> > >  	bool streaming = sensor->streaming;
> > >  	int rval;
> > >  
> > > -	rval = pm_runtime_get_sync(dev);
> > > -	if (rval < 0) {
> > > -		pm_runtime_put_noidle(dev);
> > > -
> > > +	rval = pm_runtime_resume_and_get(dev);
> > > +	if (rval < 0)
> > >  		return rval;
> > > -	}
> > >  
> > >  	if (sensor->streaming)
> > >  		ccs_stop_streaming(sensor);  
> > 
> 
> Thanks,
> Mauro
> 
> ---
> 
> [PATCH] media: i2c: ccs-core: fix pm_runtime_get_sync() usage count
> 
> The pm_runtime_get_sync() internally increments the
> dev->power.usage_count without decrementing it, even on errors.
> 
> There is a bug at ccs_pm_get_init(): when this function returns
> an error, the stream is not started, and RPM usage_count
> should not be incremented. However, if the calls to
> v4l2_ctrl_handler_setup() return errors, it will be kept
> incremented.
> 
> At ccs_suspend() the best is to replace it by the new
> pm_runtime_resume_and_get(), introduced by:
> commit dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter")
> in order to properly decrement the usage counter automatically,
> in the case of errors.
> 
> Fixes: 96e3a6b92f23 ("media: smiapp: Avoid maintaining power state information")
> Cc: stable@vger.kernel.org
> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>

> 
> diff --git a/drivers/media/i2c/ccs/ccs-core.c b/drivers/media/i2c/ccs/ccs-core.c
> index b05f409014b2..5ea471fefa3a 100644
> --- a/drivers/media/i2c/ccs/ccs-core.c
> +++ b/drivers/media/i2c/ccs/ccs-core.c
> @@ -1880,21 +1880,33 @@ static int ccs_pm_get_init(struct ccs_sensor *sensor)
>  	struct i2c_client *client = v4l2_get_subdevdata(&sensor->src->sd);
>  	int rval;
>  
> +	/*
> +	 * It can't use pm_runtime_resume_and_get() here, as the driver
> +	 * relies at the returned value to detect if the device was already
> +	 * active or not.
> +	 */
>  	rval = pm_runtime_get_sync(&client->dev);
> -	if (rval < 0) {
> -		pm_runtime_put_noidle(&client->dev);
> +	if (rval < 0)
> +		goto error;
>  
> -		return rval;
> -	} else if (!rval) {
> -		rval = v4l2_ctrl_handler_setup(&sensor->pixel_array->
> -					       ctrl_handler);
> -		if (rval)
> -			return rval;
> +	/* Device was already active, so don't set controls */
> +	if (rval == 1)
> +		return 0;
>  
> -		return v4l2_ctrl_handler_setup(&sensor->src->ctrl_handler);
> -	}
> +	/* Restore V4L2 controls to the suspended device */
> +	rval = v4l2_ctrl_handler_setup(&sensor->pixel_array->ctrl_handler);
> +	if (rval)
> +		goto error;
>  
> +	rval = v4l2_ctrl_handler_setup(&sensor->src->ctrl_handler);
> +	if (rval)
> +		goto error;
> +
> +	/* Keep PM runtime usage_count incremented on success */
>  	return 0;
> +error:
> +	pm_runtime_put(&client->dev);
> +	return rval;
>  }
>  
>  static int ccs_set_stream(struct v4l2_subdev *subdev, int enable)
> 
> 
> 
>
Jonathan Cameron May 5, 2021, 12:35 p.m. UTC | #5
On Wed, 5 May 2021 12:58:57 +0200
Mauro Carvalho Chehab <mchehab+huawei@kernel.org> wrote:

> Em Wed, 5 May 2021 12:57:00 +0200
> Mauro Carvalho Chehab <mchehab+huawei@kernel.org> escreveu:
> 
> > Em Wed, 5 May 2021 13:34:09 +0300
> > Sakari Ailus <sakari.ailus@linux.intel.com> escreveu:
> >   
> > > Hi Mauro,
> > > 
> > > Thanks for the patch.
> > > 
> > > On Wed, May 05, 2021 at 11:42:15AM +0200, Mauro Carvalho Chehab wrote:  
> > > > The pm_runtime_get_sync() internally increments the
> > > > dev->power.usage_count without decrementing it, even on errors.
> > > > 
> > > > There is a bug at ccs_pm_get_init(): when this function returns
> > > > an error, the stream is not started, and RPM usage_count
> > > > should not be incremented. However, if the calls to
> > > > v4l2_ctrl_handler_setup() return errors, it will be kept
> > > > incremented.
> > > > 
> > > > At ccs_suspend() the best is to replace it by the new
> > > > pm_runtime_resume_and_get(), introduced by:
> > > > commit dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter")
> > > > in order to properly decrement the usage counter automatically,
> > > > in the case of errors.
> > > > 
> > > > Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>    
> > > 
> > > Could you add Fixes: line and Cc: stable?  
> > 
> > Sure. See the fixes one enclosed.
> >   
> > > The patch that breaks this is 96e3a6b92f23a .
> > > 
> > > It would be better to fix the bug first so the patch to the stable trees
> > > doesn't need special handling.
> > >   
> > > > ---
> > > >  drivers/media/i2c/ccs/ccs-core.c | 39 ++++++++++++++++++++------------
> > > >  1 file changed, 24 insertions(+), 15 deletions(-)
> > > > 
> > > > diff --git a/drivers/media/i2c/ccs/ccs-core.c b/drivers/media/i2c/ccs/ccs-core.c
> > > > index b05f409014b2..04c3ab9e37b4 100644
> > > > --- a/drivers/media/i2c/ccs/ccs-core.c
> > > > +++ b/drivers/media/i2c/ccs/ccs-core.c
> > > > @@ -1880,21 +1880,33 @@ static int ccs_pm_get_init(struct ccs_sensor *sensor)
> > > >  	struct i2c_client *client = v4l2_get_subdevdata(&sensor->src->sd);
> > > >  	int rval;
> > > >  
> > > > +	/*
> > > > +	 * It can't use pm_runtime_resume_and_get() here, as the driver
> > > > +	 * relies at the returned value to detect if the device was already
> > > > +	 * active or not.
> > > > +	 */
> > > >  	rval = pm_runtime_get_sync(&client->dev);
> > > > -	if (rval < 0) {
> > > > -		pm_runtime_put_noidle(&client->dev);
> > > > +	if (rval < 0)
> > > > +		goto error;
> > > >  
> > > > -		return rval;
> > > > -	} else if (!rval) {
> > > > -		rval = v4l2_ctrl_handler_setup(&sensor->pixel_array->
> > > > -					       ctrl_handler);
> > > > -		if (rval)
> > > > -			return rval;
> > > > +	/* Device was already active, so don't set controls */
> > > > +	if (rval == 1)
> > > > +		return 0;
> > > >  
> > > > -		return v4l2_ctrl_handler_setup(&sensor->src->ctrl_handler);
> > > > -	}
> > > > +	/* Restore V4L2 controls to the suspended device */
> > > > +	rval = v4l2_ctrl_handler_setup(&sensor->pixel_array->ctrl_handler);
> > > > +	if (rval)
> > > > +		goto error;
> > > >  
> > > > +	rval = v4l2_ctrl_handler_setup(&sensor->src->ctrl_handler);
> > > > +	if (rval)
> > > > +		goto error;
> > > > +
> > > > +	/* Keep PM runtime usage_count incremented on success */
> > > >  	return 0;
> > > > +error:
> > > > +	pm_runtime_put_noidle(&client->dev);    
> > > 
> > > This needs to be pm_runtime_put() as the device has been successfully.  
> > 
> > Ok.
> >   
> > >   
> > > > +	return rval;
> > > >  }
> > > >  
> > > >  static int ccs_set_stream(struct v4l2_subdev *subdev, int enable)
> > > > @@ -3089,12 +3101,9 @@ static int __maybe_unused ccs_suspend(struct device *dev)
> > > >  	bool streaming = sensor->streaming;
> > > >  	int rval;
> > > >  
> > > > -	rval = pm_runtime_get_sync(dev);
> > > > -	if (rval < 0) {
> > > > -		pm_runtime_put_noidle(dev);
> > > > -
> > > > +	rval = pm_runtime_resume_and_get(dev);
> > > > +	if (rval < 0)
> > > >  		return rval;
> > > > -	}
> > > >  
> > > >  	if (sensor->streaming)
> > > >  		ccs_stop_streaming(sensor);    
> > >   
> > 
> > Thanks,
> > Mauro
> > 
> > ---
> > 
> > [PATCH] media: i2c: ccs-core: fix pm_runtime_get_sync() usage count
> > 
> > The pm_runtime_get_sync() internally increments the
> > dev->power.usage_count without decrementing it, even on errors.
> > 
> > There is a bug at ccs_pm_get_init(): when this function returns
> > an error, the stream is not started, and RPM usage_count
> > should not be incremented. However, if the calls to
> > v4l2_ctrl_handler_setup() return errors, it will be kept
> > incremented.
> > 
> > At ccs_suspend() the best is to replace it by the new
> > pm_runtime_resume_and_get(), introduced by:
> > commit dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter")
> > in order to properly decrement the usage counter automatically,
> > in the case of errors.
> > 
> > Fixes: 96e3a6b92f23 ("media: smiapp: Avoid maintaining power state information")
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

> > 
> > diff --git a/drivers/media/i2c/ccs/ccs-core.c b/drivers/media/i2c/ccs/ccs-core.c
> > index b05f409014b2..5ea471fefa3a 100644
> > --- a/drivers/media/i2c/ccs/ccs-core.c
> > +++ b/drivers/media/i2c/ccs/ccs-core.c
> > @@ -1880,21 +1880,33 @@ static int ccs_pm_get_init(struct ccs_sensor *sensor)
> >  	struct i2c_client *client = v4l2_get_subdevdata(&sensor->src->sd);
> >  	int rval;
> >  
> > +	/*
> > +	 * It can't use pm_runtime_resume_and_get() here, as the driver
> > +	 * relies at the returned value to detect if the device was already
> > +	 * active or not.
> > +	 */
> >  	rval = pm_runtime_get_sync(&client->dev);
> > -	if (rval < 0) {
> > -		pm_runtime_put_noidle(&client->dev);
> > +	if (rval < 0)
> > +		goto error;
> >  
> > -		return rval;
> > -	} else if (!rval) {
> > -		rval = v4l2_ctrl_handler_setup(&sensor->pixel_array->
> > -					       ctrl_handler);
> > -		if (rval)
> > -			return rval;
> > +	/* Device was already active, so don't set controls */
> > +	if (rval == 1)
> > +		return 0;
> >  
> > -		return v4l2_ctrl_handler_setup(&sensor->src->ctrl_handler);
> > -	}
> > +	/* Restore V4L2 controls to the suspended device */  
> 
> In time: I'll fold this at the patch:
> 
> diff --git a/drivers/media/i2c/ccs/ccs-core.c b/drivers/media/i2c/ccs/ccs-core.c
> index 5ea471fefa3a..4a848ac2d2cd 100644
> --- a/drivers/media/i2c/ccs/ccs-core.c
> +++ b/drivers/media/i2c/ccs/ccs-core.c
> @@ -1896 +1896 @@ static int ccs_pm_get_init(struct ccs_sensor *sensor)
> -       /* Restore V4L2 controls to the suspended device */
> +       /* Restore V4L2 controls to the previously suspended device */
> 
> Regards,
> Mauro
Mauro Carvalho Chehab May 5, 2021, 2:06 p.m. UTC | #6
Hi Jonathan,

Em Wed, 5 May 2021 13:35:48 +0100
Jonathan Cameron <Jonathan.Cameron@Huawei.com> escreveu:

> > > [PATCH] media: i2c: ccs-core: fix pm_runtime_get_sync() usage count
> > > 
> > > The pm_runtime_get_sync() internally increments the
> > > dev->power.usage_count without decrementing it, even on errors.
> > > 
> > > There is a bug at ccs_pm_get_init(): when this function returns
> > > an error, the stream is not started, and RPM usage_count
> > > should not be incremented. However, if the calls to
> > > v4l2_ctrl_handler_setup() return errors, it will be kept
> > > incremented.
> > > 
> > > At ccs_suspend() the best is to replace it by the new
> > > pm_runtime_resume_and_get(), introduced by:
> > > commit dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter")
> > > in order to properly decrement the usage counter automatically,
> > > in the case of errors.
> > > 
> > > Fixes: 96e3a6b92f23 ("media: smiapp: Avoid maintaining power state information")
> > > Cc: stable@vger.kernel.org
> > > Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>  
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Per Sakari's request (for practical reasons on backporting and
c/c stable), this was split into two separate patches, one
fixing the issues, and a separate trivial one with just the
pm_runtime_resume_and_get(). I'm adding your RB on both.

Thanks,
Mauro
Jonathan Cameron May 5, 2021, 4:36 p.m. UTC | #7
On Wed, 5 May 2021 16:06:45 +0200
Mauro Carvalho Chehab <mchehab+huawei@kernel.org> wrote:

> Hi Jonathan,
> 
> Em Wed, 5 May 2021 13:35:48 +0100
> Jonathan Cameron <Jonathan.Cameron@Huawei.com> escreveu:
> 
> > > > [PATCH] media: i2c: ccs-core: fix pm_runtime_get_sync() usage count
> > > > 
> > > > The pm_runtime_get_sync() internally increments the
> > > > dev->power.usage_count without decrementing it, even on errors.
> > > > 
> > > > There is a bug at ccs_pm_get_init(): when this function returns
> > > > an error, the stream is not started, and RPM usage_count
> > > > should not be incremented. However, if the calls to
> > > > v4l2_ctrl_handler_setup() return errors, it will be kept
> > > > incremented.
> > > > 
> > > > At ccs_suspend() the best is to replace it by the new
> > > > pm_runtime_resume_and_get(), introduced by:
> > > > commit dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter")
> > > > in order to properly decrement the usage counter automatically,
> > > > in the case of errors.
> > > > 
> > > > Fixes: 96e3a6b92f23 ("media: smiapp: Avoid maintaining power state information")
> > > > Cc: stable@vger.kernel.org
> > > > Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>    
> > Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>  
> 
> Per Sakari's request (for practical reasons on backporting and
> c/c stable), this was split into two separate patches, one
> fixing the issues, and a separate trivial one with just the
> pm_runtime_resume_and_get(). I'm adding your RB on both.
Makes sense.

Jonathan

> 
> Thanks,
> Mauro

Patch
diff mbox series

diff --git a/drivers/media/i2c/ccs/ccs-core.c b/drivers/media/i2c/ccs/ccs-core.c
index b05f409014b2..04c3ab9e37b4 100644
--- a/drivers/media/i2c/ccs/ccs-core.c
+++ b/drivers/media/i2c/ccs/ccs-core.c
@@ -1880,21 +1880,33 @@  static int ccs_pm_get_init(struct ccs_sensor *sensor)
 	struct i2c_client *client = v4l2_get_subdevdata(&sensor->src->sd);
 	int rval;
 
+	/*
+	 * It can't use pm_runtime_resume_and_get() here, as the driver
+	 * relies at the returned value to detect if the device was already
+	 * active or not.
+	 */
 	rval = pm_runtime_get_sync(&client->dev);
-	if (rval < 0) {
-		pm_runtime_put_noidle(&client->dev);
+	if (rval < 0)
+		goto error;
 
-		return rval;
-	} else if (!rval) {
-		rval = v4l2_ctrl_handler_setup(&sensor->pixel_array->
-					       ctrl_handler);
-		if (rval)
-			return rval;
+	/* Device was already active, so don't set controls */
+	if (rval == 1)
+		return 0;
 
-		return v4l2_ctrl_handler_setup(&sensor->src->ctrl_handler);
-	}
+	/* Restore V4L2 controls to the suspended device */
+	rval = v4l2_ctrl_handler_setup(&sensor->pixel_array->ctrl_handler);
+	if (rval)
+		goto error;
 
+	rval = v4l2_ctrl_handler_setup(&sensor->src->ctrl_handler);
+	if (rval)
+		goto error;
+
+	/* Keep PM runtime usage_count incremented on success */
 	return 0;
+error:
+	pm_runtime_put_noidle(&client->dev);
+	return rval;
 }
 
 static int ccs_set_stream(struct v4l2_subdev *subdev, int enable)
@@ -3089,12 +3101,9 @@  static int __maybe_unused ccs_suspend(struct device *dev)
 	bool streaming = sensor->streaming;
 	int rval;
 
-	rval = pm_runtime_get_sync(dev);
-	if (rval < 0) {
-		pm_runtime_put_noidle(dev);
-
+	rval = pm_runtime_resume_and_get(dev);
+	if (rval < 0)
 		return rval;
-	}
 
 	if (sensor->streaming)
 		ccs_stop_streaming(sensor);