This allows one to simplify drivers that provide a trigger with a non-constant name (e.g. one trigger per device with the trigger name depending on the device's name).
Internally the memory the name member of struct led_trigger points to now always allocated dynamically instead of just taken from the caller. The function led_trigger_rename_static() must be changed accordingly and was renamed to led_trigger_rename() for consistency, with the only user adapted. Signed-off-by: Uwe Kleine-König <[email protected]> --- drivers/leds/led-triggers.c | 84 +++++++++++++++++++++++++++---------- drivers/net/can/led.c | 6 +-- include/linux/leds.h | 30 +++++++------ 3 files changed, 81 insertions(+), 39 deletions(-) diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c index 431123b048a2..5d8bb504b07b 100644 --- a/drivers/leds/led-triggers.c +++ b/drivers/leds/led-triggers.c @@ -175,18 +175,34 @@ void led_trigger_set_default(struct led_classdev *led_cdev) } EXPORT_SYMBOL_GPL(led_trigger_set_default); -void led_trigger_rename_static(const char *name, struct led_trigger *trig) +int led_trigger_rename(struct led_trigger *trig, const char *fmt, ...) { - /* new name must be on a temporary string to prevent races */ - BUG_ON(name == trig->name); + const char *prevname; + const char *newname; + va_list args; + + if (!trig) + return 0; + + va_start(args, fmt); + newname = kvasprintf_const(GFP_KERNEL, fmt, args); + va_end(args); + + if (!newname) { + pr_err("Failed to allocate new name for trigger %s\n", trig->name); + return -ENOMEM; + } down_write(&triggers_list_lock); - /* this assumes that trig->name was originaly allocated to - * non constant storage */ - strcpy((char *)trig->name, name); + prevname = trig->name; + trig->name = newname; up_write(&triggers_list_lock); + + kfree_const(prevname); + + return 0; } -EXPORT_SYMBOL_GPL(led_trigger_rename_static); +EXPORT_SYMBOL_GPL(led_trigger_rename); /* LED Trigger Interface */ @@ -333,34 +349,56 @@ void led_trigger_blink_oneshot(struct led_trigger *trig, } EXPORT_SYMBOL_GPL(led_trigger_blink_oneshot); -void led_trigger_register_simple(const char *name, struct led_trigger **tp) +int led_trigger_register_format(struct led_trigger **tp, const char *fmt, ...) { + va_list args; struct led_trigger *trig; - int err; + int err = -ENOMEM; + const char *name; + + va_start(args, fmt); + name = kvasprintf_const(GFP_KERNEL, fmt, args); + va_end(args); trig = kzalloc(sizeof(struct led_trigger), GFP_KERNEL); - if (trig) { - trig->name = name; - err = led_trigger_register(trig); - if (err < 0) { - kfree(trig); - trig = NULL; - pr_warn("LED trigger %s failed to register (%d)\n", - name, err); - } - } else { - pr_warn("LED trigger %s failed to register (no memory)\n", - name); - } + if (!name || !trig) + goto err; + + trig->name = name; + + err = led_trigger_register(trig); + if (err < 0) + goto err; + *tp = trig; + + return 0; + +err: + kfree(trig); + kfree_const(name); + + *tp = NULL; + + return err; +} +EXPORT_SYMBOL_GPL(led_trigger_register_format); + +void led_trigger_register_simple(const char *name, struct led_trigger **tp) +{ + int ret = led_trigger_register_format(tp, "%s", name); + if (ret < 0) + pr_warn("LED trigger %s failed to register (%d)\n", name, ret); } EXPORT_SYMBOL_GPL(led_trigger_register_simple); void led_trigger_unregister_simple(struct led_trigger *trig) { - if (trig) + if (trig) { led_trigger_unregister(trig); + kfree_const(trig->name); + } kfree(trig); } EXPORT_SYMBOL_GPL(led_trigger_unregister_simple); diff --git a/drivers/net/can/led.c b/drivers/net/can/led.c index c1b667675fa1..2d7d1b0d20f9 100644 --- a/drivers/net/can/led.c +++ b/drivers/net/can/led.c @@ -115,13 +115,13 @@ static int can_led_notifier(struct notifier_block *nb, unsigned long msg, if (msg == NETDEV_CHANGENAME) { snprintf(name, sizeof(name), "%s-tx", netdev->name); - led_trigger_rename_static(name, priv->tx_led_trig); + led_trigger_rename(priv->tx_led_trig, name); snprintf(name, sizeof(name), "%s-rx", netdev->name); - led_trigger_rename_static(name, priv->rx_led_trig); + led_trigger_rename(priv->rx_led_trig, name); snprintf(name, sizeof(name), "%s-rxtx", netdev->name); - led_trigger_rename_static(name, priv->rxtx_led_trig); + led_trigger_rename(priv->rxtx_led_trig, name); } return NOTIFY_DONE; diff --git a/include/linux/leds.h b/include/linux/leds.h index b7e82550e655..e706c28bb35b 100644 --- a/include/linux/leds.h +++ b/include/linux/leds.h @@ -275,6 +275,8 @@ extern void led_trigger_unregister(struct led_trigger *trigger); extern int devm_led_trigger_register(struct device *dev, struct led_trigger *trigger); +extern int led_trigger_register_format(struct led_trigger **trigger, + const char *fmt, ...); extern void led_trigger_register_simple(const char *name, struct led_trigger **trigger); extern void led_trigger_unregister_simple(struct led_trigger *trigger); @@ -298,28 +300,25 @@ static inline void *led_get_trigger_data(struct led_classdev *led_cdev) } /** - * led_trigger_rename_static - rename a trigger - * @name: the new trigger name + * led_trigger_rename - rename a trigger * @trig: the LED trigger to rename + * @fmt: format string for new name * - * Change a LED trigger name by copying the string passed in - * name into current trigger name, which MUST be large - * enough for the new string. - * - * Note that name must NOT point to the same string used - * during LED registration, as that could lead to races. - * - * This is meant to be used on triggers with statically - * allocated name. + * rebaptize the given trigger. */ -extern void led_trigger_rename_static(const char *name, - struct led_trigger *trig); +extern int led_trigger_rename(struct led_trigger *trig, const char *fmt, ...); #else /* Trigger has no members */ struct led_trigger {}; +static inline int led_trigger_register_format(struct led_trigger **trigger, + const char *fmt, ...) +{ + return 0; +} + /* Trigger inline empty functions */ static inline void led_trigger_register_simple(const char *name, struct led_trigger **trigger) {} @@ -342,6 +341,11 @@ static inline void *led_get_trigger_data(struct led_classdev *led_cdev) return NULL; } +static inline int led_trigger_rename(struct led_trigger *trig, const char *fmt, ...) +{ + return 0; +} + #endif /* CONFIG_LEDS_TRIGGERS */ /* Trigger specific functions */ -- 2.17.0
