[PATCH 3.16 031/306] pwm: Unexport children before chip removal

Ben Hutchings
2017-02-15T23:58:24Z

From: David Hsu <davidhsu@google.com>

commit 0733424c9ba9f42242409d1ece780777272f7ea1 upstream.

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>
Fixes: 76abbdde2d95 ("pwm: Add sysfs interface")
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/pwm/core.c | 2 ++
drivers/pwm/sysfs.c | 18 ++++++++++++++++++
include/linux/pwm.h | 5 +++++
3 files changed, 25 insertions(+)

--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -293,6 +293,8 @@ 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++) {
--- a/drivers/pwm/sysfs.c
+++ b/drivers/pwm/sysfs.c
@@ -340,6 +340,24 @@ void pwmchip_sysfs_unexport(struct pwm_c
}
}

+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);
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -299,6 +299,7 @@ static inline void pwm_add_table(struct
#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)
{
@@ -307,6 +308,10 @@ static inline void pwmchip_sysfs_export(
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 */