[PATCH] pwm: Unexport children before chip removal

[PATCH] pwm: Unexport children before chip removal

[David Hsu]

Exported pwm channels aren't removed before the pwmchip and are
leaked. This results in invalid sysfs files. This fix removes
all exported pwm channels before chip removal.

Signed-off-by: David Hsu <davidhsu@google.com>
---
 drivers/pwm/core.c  |  2 ++
 drivers/pwm/sysfs.c | 18 ++++++++++++++++++
 include/linux/pwm.h |  5 +++++
 3 files changed, 25 insertions(+)

diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index ed337a8c..869af84 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -339,6 +339,8 @@ int pwmchip_remove(struct pwm_chip *chip)
 	unsigned int i;
 	int ret = 0;
 
+	pwmchip_sysfs_unexport_children(chip);
+
 	mutex_lock(&pwm_lock);
 
 	for (i = 0; i < chip->npwm; i++) {
diff --git a/drivers/pwm/sysfs.c b/drivers/pwm/sysfs.c
index cb2b376..b3ccb8f 100644
--- a/drivers/pwm/sysfs.c
+++ b/drivers/pwm/sysfs.c
@@ -400,6 +400,24 @@ void pwmchip_sysfs_unexport(struct pwm_chip *chip)
 	}
 }
 
+void pwmchip_sysfs_unexport_children(struct pwm_chip *chip)
+{
+	struct device *parent;
+	unsigned int i;
+
+	parent = class_find_device(&pwm_class, NULL, chip,
+				   pwmchip_sysfs_match);
+	if (!parent)
+		return;
+
+	for (i = 0; i < chip->npwm; i++) {
+		struct pwm_device *pwm = &chip->pwms[i];
+
+		if (test_bit(PWMF_EXPORTED, &pwm->flags))
+			pwm_unexport_child(parent, pwm);
+	}
+}
+
 static int __init pwm_sysfs_init(void)
 {
 	return class_register(&pwm_class);
diff --git a/include/linux/pwm.h b/include/linux/pwm.h
index c038ae3..16a0ae0 100644
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -530,6 +530,7 @@ static inline void pwm_remove_table(struct pwm_lookup *table, size_t num)
 #ifdef CONFIG_PWM_SYSFS
 void pwmchip_sysfs_export(struct pwm_chip *chip);
 void pwmchip_sysfs_unexport(struct pwm_chip *chip);
+void pwmchip_sysfs_unexport_children(struct pwm_chip *chip);
 #else
 static inline void pwmchip_sysfs_export(struct pwm_chip *chip)
 {
@@ -538,6 +539,10 @@ static inline void pwmchip_sysfs_export(struct pwm_chip *chip)
 static inline void pwmchip_sysfs_unexport(struct pwm_chip *chip)
 {
 }
+
+static inline void pwmchip_sysfs_unexport_children(struct pwm_chip *chip)
+{
+}
 #endif /* CONFIG_PWM_SYSFS */
 
 #endif /* __LINUX_PWM_H */
-- 
2.8.0.rc3.226.g39d4020

Re: [PATCH] pwm: Unexport children before chip removal

[Greg KH]

On Tue, Aug 09, 2016 at 02:57:46PM -0700, David Hsu wrote:
> Exported pwm channels aren't removed before the pwmchip and are
> leaked. This results in invalid sysfs files. This fix removes
> all exported pwm channels before chip removal.
> 
> Signed-off-by: David Hsu <davidhsu@google.com>
> ---
>  drivers/pwm/core.c  |  2 ++
>  drivers/pwm/sysfs.c | 18 ++++++++++++++++++
>  include/linux/pwm.h |  5 +++++
>  3 files changed, 25 insertions(+)

Should this also go to the stable kernel releases?

thanks,

greg k-h

Re: [PATCH] pwm: Unexport children before chip removal

[David Hsu]

On Wed, Aug 10, 2016 at 1:49 AM, Greg KH <gregkh@linuxfoundation.org> wrote:
> On Tue, Aug 09, 2016 at 02:57:46PM -0700, David Hsu wrote:
>> Exported pwm channels aren't removed before the pwmchip and are
>> leaked. This results in invalid sysfs files. This fix removes
>> all exported pwm channels before chip removal.
>>
>> Signed-off-by: David Hsu <davidhsu@google.com>
>> ---
>>  drivers/pwm/core.c  |  2 ++
>>  drivers/pwm/sysfs.c | 18 ++++++++++++++++++
>>  include/linux/pwm.h |  5 +++++
>>  3 files changed, 25 insertions(+)
>
> Should this also go to the stable kernel releases?
>

Yes, this should go into stable.

Thanks,
David

> thanks,
>
> greg k-h

Re: [PATCH] pwm: Unexport children before chip removal

[Thierry Reding]

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On Tue, Aug 09, 2016 at 02:57:46PM -0700, David Hsu wrote:
> Exported pwm channels aren't removed before the pwmchip and are
> leaked. This results in invalid sysfs files. This fix removes
> all exported pwm channels before chip removal.
> 
> Signed-off-by: David Hsu <davidhsu@google.com>
> ---
>  drivers/pwm/core.c  |  2 ++
>  drivers/pwm/sysfs.c | 18 ++++++++++++++++++
>  include/linux/pwm.h |  5 +++++
>  3 files changed, 25 insertions(+)

I've applied this with the following added to the commit message:

	Fixes: 76abbdde2d95 ("pwm: Add sysfs interface")

since this seems to have been wrong since forever.

Thierry

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Re: [PATCH] pwm: Unexport children before chip removal

[Greg KH]

On Mon, Sep 05, 2016 at 04:46:41PM +0200, Thierry Reding wrote:
> On Tue, Aug 09, 2016 at 02:57:46PM -0700, David Hsu wrote:
> > Exported pwm channels aren't removed before the pwmchip and are
> > leaked. This results in invalid sysfs files. This fix removes
> > all exported pwm channels before chip removal.
> > 
> > Signed-off-by: David Hsu <davidhsu@google.com>
> > ---
> >  drivers/pwm/core.c  |  2 ++
> >  drivers/pwm/sysfs.c | 18 ++++++++++++++++++
> >  include/linux/pwm.h |  5 +++++
> >  3 files changed, 25 insertions(+)
> 
> I've applied this with the following added to the commit message:
> 
> 	Fixes: 76abbdde2d95 ("pwm: Add sysfs interface")
> 
> since this seems to have been wrong since forever.

Wonderful, thanks for doing that.

greg k-h