| Message ID | 1459801326-5541-2-git-send-email-ezequiel@vanguardiasur.com.ar (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Ezequiel, Thanks for the patch. I have one comment below. On 04/04/2016 10:22 PM, Ezequiel Garcia wrote: > This commit adds a new led_cdev flag LED_BLINK_AT_PANIC, which > allows to mark a specific LED to be switched to the "panic" > trigger, on a kernel panic. > > This is useful to allow the user to assign a regular trigger > to a given LED, and still blink that LED on a kernel panic. > > Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar> > --- > drivers/leds/led-triggers.c | 52 +++++++++++++++++++++++++++++++++++++++++++++ > include/linux/leds.h | 1 + > 2 files changed, 53 insertions(+) > > diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c > index 2181581795d3..f5c9d7c4d181 100644 > --- a/drivers/leds/led-triggers.c > +++ b/drivers/leds/led-triggers.c > @@ -148,6 +148,43 @@ void led_trigger_remove(struct led_classdev *led_cdev) > } > EXPORT_SYMBOL_GPL(led_trigger_remove); > > +/* > + * This is a called in a special context by the atomic panic > + * notifier. This means the trigger can be changed without > + * worrying about locking. > + */ > +static void led_trigger_set_panic(struct led_classdev *led_cdev) > +{ > + struct led_trigger *trig; > + > + list_for_each_entry(trig, &trigger_list, next_trig) { > + if (strcmp("panic", trig->name)) > + continue; > + if (led_cdev->trigger) > + list_del(&led_cdev->trig_list); > + list_add_tail(&led_cdev->trig_list, &trig->led_cdevs); > + led_cdev->trigger = trig; > + if (trig->activate) > + trig->activate(led_cdev); > + break; > + } > +} > + > +static int led_trigger_panic_notifier(struct notifier_block *nb, > + unsigned long code, void *unused) > +{ > + struct led_classdev *led_cdev; > + > + list_for_each_entry(led_cdev, &leds_list, node) > + if (led_cdev->flags & LED_BLINK_AT_PANIC) > + led_trigger_set_panic(led_cdev); > + return NOTIFY_DONE; > +} > + > +static struct notifier_block led_trigger_panic_nb = { > + .notifier_call = led_trigger_panic_notifier, > +}; > + > void led_trigger_set_default(struct led_classdev *led_cdev) > { > struct led_trigger *trig; > @@ -356,6 +393,21 @@ void led_trigger_unregister_simple(struct led_trigger *trig) > } > EXPORT_SYMBOL_GPL(led_trigger_unregister_simple); > > +static int __init leds_trigger_init(void) > +{ > + atomic_notifier_chain_register(&panic_notifier_list, > + &led_trigger_panic_nb); > + return 0; > +} > + > +static void __exit leds_trigger_exit(void) > +{ > + atomic_notifier_chain_unregister(&panic_notifier_list, > + &led_trigger_panic_nb); > +} > +module_init(leds_trigger_init); > +module_exit(leds_trigger_exit); > + > MODULE_AUTHOR("Richard Purdie"); > MODULE_LICENSE("GPL"); > MODULE_DESCRIPTION("LED Triggers Core"); > diff --git a/include/linux/leds.h b/include/linux/leds.h > index f203a8f89d30..7f1428bb1e69 100644 > --- a/include/linux/leds.h > +++ b/include/linux/leds.h > @@ -50,6 +50,7 @@ struct led_classdev { > #define LED_SYSFS_DISABLE (1 << 22) > #define LED_DEV_CAP_FLASH (1 << 23) > #define LED_HW_PLUGGABLE (1 << 24) > +#define LED_BLINK_AT_PANIC (1 << 25) LED_BLINK prefixed macros control LED subsystem inherent blinking feature. Would you mind renaming it to LED_PANIC_INDICATOR? > > /* Set LED brightness level > * Must not sleep. Use brightness_set_blocking for drivers >
On Mon 2016-04-04 17:22:02, Ezequiel Garcia wrote: > This commit adds a new led_cdev flag LED_BLINK_AT_PANIC, which > allows to mark a specific LED to be switched to the "panic" > trigger, on a kernel panic. > > This is useful to allow the user to assign a regular trigger > to a given LED, and still blink that LED on a kernel panic. > > Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar> > drivers/leds/led-triggers.c | 52 +++++++++++++++++++++++++++++++++++++++++++++ > include/linux/leds.h | 1 + Could we get this out of the core? I'm pretty sure most users are not interested... Pavel > +/* > + * This is a called in a special context by the atomic panic > + * notifier. This means the trigger can be changed without > + * worrying about locking. > + */ > +static void led_trigger_set_panic(struct led_classdev *led_cdev) > +{ > + struct led_trigger *trig; > + > + list_for_each_entry(trig, &trigger_list, next_trig) { > + if (strcmp("panic", trig->name)) > + continue; > + if (led_cdev->trigger) > + list_del(&led_cdev->trig_list); > + list_add_tail(&led_cdev->trig_list, &trig->led_cdevs); > + led_cdev->trigger = trig; > + if (trig->activate) > + trig->activate(led_cdev); > + break; > + } > +} > + > +static int led_trigger_panic_notifier(struct notifier_block *nb, > + unsigned long code, void *unused) > +{ > + struct led_classdev *led_cdev; > + > + list_for_each_entry(led_cdev, &leds_list, node) > + if (led_cdev->flags & LED_BLINK_AT_PANIC) > + led_trigger_set_panic(led_cdev); > + return NOTIFY_DONE; > +} > + > +static struct notifier_block led_trigger_panic_nb = { > + .notifier_call = led_trigger_panic_notifier, > +}; > + > void led_trigger_set_default(struct led_classdev *led_cdev) > { > struct led_trigger *trig; > @@ -356,6 +393,21 @@ void led_trigger_unregister_simple(struct led_trigger *trig) > } > EXPORT_SYMBOL_GPL(led_trigger_unregister_simple); > > +static int __init leds_trigger_init(void) > +{ > + atomic_notifier_chain_register(&panic_notifier_list, > + &led_trigger_panic_nb); > + return 0; > +} > + > +static void __exit leds_trigger_exit(void) > +{ > + atomic_notifier_chain_unregister(&panic_notifier_list, > + &led_trigger_panic_nb); > +} > +module_init(leds_trigger_init); > +module_exit(leds_trigger_exit); > + > MODULE_AUTHOR("Richard Purdie"); > MODULE_LICENSE("GPL"); > MODULE_DESCRIPTION("LED Triggers Core"); > diff --git a/include/linux/leds.h b/include/linux/leds.h > index f203a8f89d30..7f1428bb1e69 100644 > --- a/include/linux/leds.h > +++ b/include/linux/leds.h > @@ -50,6 +50,7 @@ struct led_classdev { > #define LED_SYSFS_DISABLE (1 << 22) > #define LED_DEV_CAP_FLASH (1 << 23) > #define LED_HW_PLUGGABLE (1 << 24) > +#define LED_BLINK_AT_PANIC (1 << 25) > > /* Set LED brightness level > * Must not sleep. Use brightness_set_blocking for drivers
On Sun 2016-04-24 11:25:51, Pavel Machek wrote: > On Mon 2016-04-04 17:22:02, Ezequiel Garcia wrote: > > This commit adds a new led_cdev flag LED_BLINK_AT_PANIC, which > > allows to mark a specific LED to be switched to the "panic" > > trigger, on a kernel panic. > > > > This is useful to allow the user to assign a regular trigger > > to a given LED, and still blink that LED on a kernel panic. > > > > Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar> > > > > drivers/leds/led-triggers.c | 52 +++++++++++++++++++++++++++++++++++++++++++++ > > include/linux/leds.h | 1 + > > Could we get this out of the core? I'm pretty sure most users are not > interested... Thinking about it some more.... This is not really a trigger. This is very special. Maybe hard-coded handling, like we do for keyboard leds on x86 would be suitable? > > Pavel > > > +/* > > + * This is a called in a special context by the atomic panic > > + * notifier. This means the trigger can be changed without > > + * worrying about locking. > > + */ > > +static void led_trigger_set_panic(struct led_classdev *led_cdev) > > +{ > > + struct led_trigger *trig; > > + > > + list_for_each_entry(trig, &trigger_list, next_trig) { > > + if (strcmp("panic", trig->name)) > > + continue; > > + if (led_cdev->trigger) > > + list_del(&led_cdev->trig_list); > > + list_add_tail(&led_cdev->trig_list, &trig->led_cdevs); > > + led_cdev->trigger = trig; > > + if (trig->activate) > > + trig->activate(led_cdev); > > + break; > > + } > > +} > > + > > +static int led_trigger_panic_notifier(struct notifier_block *nb, > > + unsigned long code, void *unused) > > +{ > > + struct led_classdev *led_cdev; > > + > > + list_for_each_entry(led_cdev, &leds_list, node) > > + if (led_cdev->flags & LED_BLINK_AT_PANIC) > > + led_trigger_set_panic(led_cdev); > > + return NOTIFY_DONE; > > +} > > + > > +static struct notifier_block led_trigger_panic_nb = { > > + .notifier_call = led_trigger_panic_notifier, > > +}; > > + > > void led_trigger_set_default(struct led_classdev *led_cdev) > > { > > struct led_trigger *trig; > > @@ -356,6 +393,21 @@ void led_trigger_unregister_simple(struct led_trigger *trig) > > } > > EXPORT_SYMBOL_GPL(led_trigger_unregister_simple); > > > > +static int __init leds_trigger_init(void) > > +{ > > + atomic_notifier_chain_register(&panic_notifier_list, > > + &led_trigger_panic_nb); > > + return 0; > > +} > > + > > +static void __exit leds_trigger_exit(void) > > +{ > > + atomic_notifier_chain_unregister(&panic_notifier_list, > > + &led_trigger_panic_nb); > > +} > > +module_init(leds_trigger_init); > > +module_exit(leds_trigger_exit); > > + > > MODULE_AUTHOR("Richard Purdie"); > > MODULE_LICENSE("GPL"); > > MODULE_DESCRIPTION("LED Triggers Core"); > > diff --git a/include/linux/leds.h b/include/linux/leds.h > > index f203a8f89d30..7f1428bb1e69 100644 > > --- a/include/linux/leds.h > > +++ b/include/linux/leds.h > > @@ -50,6 +50,7 @@ struct led_classdev { > > #define LED_SYSFS_DISABLE (1 << 22) > > #define LED_DEV_CAP_FLASH (1 << 23) > > #define LED_HW_PLUGGABLE (1 << 24) > > +#define LED_BLINK_AT_PANIC (1 << 25) > > > > /* Set LED brightness level > > * Must not sleep. Use brightness_set_blocking for drivers >
On 04/24/2016 11:29 AM, Pavel Machek wrote: > On Sun 2016-04-24 11:25:51, Pavel Machek wrote: >> On Mon 2016-04-04 17:22:02, Ezequiel Garcia wrote: >>> This commit adds a new led_cdev flag LED_BLINK_AT_PANIC, which >>> allows to mark a specific LED to be switched to the "panic" >>> trigger, on a kernel panic. >>> >>> This is useful to allow the user to assign a regular trigger >>> to a given LED, and still blink that LED on a kernel panic. >>> >>> Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar> >> >> >>> drivers/leds/led-triggers.c | 52 +++++++++++++++++++++++++++++++++++++++++++++ >>> include/linux/leds.h | 1 + >> >> Could we get this out of the core? I'm pretty sure most users are not >> interested... Good point. > Thinking about it some more.... > > This is not really a trigger. This is very special. Maybe hard-coded > handling, like we do for keyboard leds on x86 would be suitable? Could you please spot the piece of code you have on mind? > > >> >> Pavel >> >>> +/* >>> + * This is a called in a special context by the atomic panic >>> + * notifier. This means the trigger can be changed without >>> + * worrying about locking. >>> + */ >>> +static void led_trigger_set_panic(struct led_classdev *led_cdev) >>> +{ >>> + struct led_trigger *trig; >>> + >>> + list_for_each_entry(trig, &trigger_list, next_trig) { >>> + if (strcmp("panic", trig->name)) >>> + continue; >>> + if (led_cdev->trigger) >>> + list_del(&led_cdev->trig_list); >>> + list_add_tail(&led_cdev->trig_list, &trig->led_cdevs); >>> + led_cdev->trigger = trig; >>> + if (trig->activate) >>> + trig->activate(led_cdev); >>> + break; >>> + } >>> +} >>> + >>> +static int led_trigger_panic_notifier(struct notifier_block *nb, >>> + unsigned long code, void *unused) >>> +{ >>> + struct led_classdev *led_cdev; >>> + >>> + list_for_each_entry(led_cdev, &leds_list, node) >>> + if (led_cdev->flags & LED_BLINK_AT_PANIC) >>> + led_trigger_set_panic(led_cdev); >>> + return NOTIFY_DONE; >>> +} >>> + >>> +static struct notifier_block led_trigger_panic_nb = { >>> + .notifier_call = led_trigger_panic_notifier, >>> +}; >>> + >>> void led_trigger_set_default(struct led_classdev *led_cdev) >>> { >>> struct led_trigger *trig; >>> @@ -356,6 +393,21 @@ void led_trigger_unregister_simple(struct led_trigger *trig) >>> } >>> EXPORT_SYMBOL_GPL(led_trigger_unregister_simple); >>> >>> +static int __init leds_trigger_init(void) >>> +{ >>> + atomic_notifier_chain_register(&panic_notifier_list, >>> + &led_trigger_panic_nb); >>> + return 0; >>> +} >>> + >>> +static void __exit leds_trigger_exit(void) >>> +{ >>> + atomic_notifier_chain_unregister(&panic_notifier_list, >>> + &led_trigger_panic_nb); >>> +} >>> +module_init(leds_trigger_init); >>> +module_exit(leds_trigger_exit); >>> + >>> MODULE_AUTHOR("Richard Purdie"); >>> MODULE_LICENSE("GPL"); >>> MODULE_DESCRIPTION("LED Triggers Core"); >>> diff --git a/include/linux/leds.h b/include/linux/leds.h >>> index f203a8f89d30..7f1428bb1e69 100644 >>> --- a/include/linux/leds.h >>> +++ b/include/linux/leds.h >>> @@ -50,6 +50,7 @@ struct led_classdev { >>> #define LED_SYSFS_DISABLE (1 << 22) >>> #define LED_DEV_CAP_FLASH (1 << 23) >>> #define LED_HW_PLUGGABLE (1 << 24) >>> +#define LED_BLINK_AT_PANIC (1 << 25) >>> >>> /* Set LED brightness level >>> * Must not sleep. Use brightness_set_blocking for drivers >> >
On 25 April 2016 at 03:56, Jacek Anaszewski <j.anaszewski@samsung.com> wrote: > On 04/24/2016 11:29 AM, Pavel Machek wrote: >> >> On Sun 2016-04-24 11:25:51, Pavel Machek wrote: >>> >>> On Mon 2016-04-04 17:22:02, Ezequiel Garcia wrote: >>>> >>>> This commit adds a new led_cdev flag LED_BLINK_AT_PANIC, which >>>> allows to mark a specific LED to be switched to the "panic" >>>> trigger, on a kernel panic. >>>> >>>> This is useful to allow the user to assign a regular trigger >>>> to a given LED, and still blink that LED on a kernel panic. >>>> >>>> Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar> >>> >>> >>> >>>> drivers/leds/led-triggers.c | 52 >>>> +++++++++++++++++++++++++++++++++++++++++++++ >>>> include/linux/leds.h | 1 + >>> >>> >>> Could we get this out of the core? I'm pretty sure most users are not >>> interested... > > > Good point. > Not sure how we can get it out of the core, and still implement it. The goal is to run-time switch user-specified LEDs and blink them when the kernel panics, and so it needs to mess up with some core private structures. Unless we don't want this feature at all.
Hi Ezequiel, On 04/25/2016 06:27 PM, Ezequiel Garcia wrote: > On 25 April 2016 at 03:56, Jacek Anaszewski <j.anaszewski@samsung.com> wrote: >> On 04/24/2016 11:29 AM, Pavel Machek wrote: >>> >>> On Sun 2016-04-24 11:25:51, Pavel Machek wrote: >>>> >>>> On Mon 2016-04-04 17:22:02, Ezequiel Garcia wrote: >>>>> >>>>> This commit adds a new led_cdev flag LED_BLINK_AT_PANIC, which >>>>> allows to mark a specific LED to be switched to the "panic" >>>>> trigger, on a kernel panic. >>>>> >>>>> This is useful to allow the user to assign a regular trigger >>>>> to a given LED, and still blink that LED on a kernel panic. >>>>> >>>>> Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar> >>>> >>>> >>>> >>>>> drivers/leds/led-triggers.c | 52 >>>>> +++++++++++++++++++++++++++++++++++++++++++++ >>>>> include/linux/leds.h | 1 + >>>> >>>> >>>> Could we get this out of the core? I'm pretty sure most users are not >>>> interested... >> >> >> Good point. >> > > Not sure how we can get it out of the core, and still implement it. > > The goal is to run-time switch user-specified LEDs and blink them when > the kernel panics, and so it needs to mess up with some core private > structures. > > Unless we don't want this feature at all. > It seems that the entire added code can be easily moved to a separate module, let's say led-panic-notifier.c ? It should select LEDS_TRIGGER_PANIC, as it would make no sense to have the former enabled without the latter.
On 26 April 2016 at 04:15, Jacek Anaszewski <j.anaszewski@samsung.com> wrote: > Hi Ezequiel, > > On 04/25/2016 06:27 PM, Ezequiel Garcia wrote: >> >> On 25 April 2016 at 03:56, Jacek Anaszewski <j.anaszewski@samsung.com> >> wrote: >>> >>> On 04/24/2016 11:29 AM, Pavel Machek wrote: >>>> >>>> >>>> On Sun 2016-04-24 11:25:51, Pavel Machek wrote: >>>>> >>>>> >>>>> On Mon 2016-04-04 17:22:02, Ezequiel Garcia wrote: >>>>>> >>>>>> >>>>>> This commit adds a new led_cdev flag LED_BLINK_AT_PANIC, which >>>>>> allows to mark a specific LED to be switched to the "panic" >>>>>> trigger, on a kernel panic. >>>>>> >>>>>> This is useful to allow the user to assign a regular trigger >>>>>> to a given LED, and still blink that LED on a kernel panic. >>>>>> >>>>>> Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar> >>>>> >>>>> >>>>> >>>>> >>>>>> drivers/leds/led-triggers.c | 52 >>>>>> +++++++++++++++++++++++++++++++++++++++++++++ >>>>>> include/linux/leds.h | 1 + >>>>> >>>>> >>>>> >>>>> Could we get this out of the core? I'm pretty sure most users are not >>>>> interested... >>> >>> >>> >>> Good point. >>> >> >> Not sure how we can get it out of the core, and still implement it. >> >> The goal is to run-time switch user-specified LEDs and blink them when >> the kernel panics, and so it needs to mess up with some core private >> structures. >> >> Unless we don't want this feature at all. >> > > It seems that the entire added code can be easily moved to a separate > module, let's say led-panic-notifier.c ? It should select > LEDS_TRIGGER_PANIC, as it would make no sense to have the former enabled > without the latter. > OK, let me try that.
On Mon 2016-04-25 08:56:46, Jacek Anaszewski wrote: > On 04/24/2016 11:29 AM, Pavel Machek wrote: > >On Sun 2016-04-24 11:25:51, Pavel Machek wrote: > >>On Mon 2016-04-04 17:22:02, Ezequiel Garcia wrote: > >>>This commit adds a new led_cdev flag LED_BLINK_AT_PANIC, which > >>>allows to mark a specific LED to be switched to the "panic" > >>>trigger, on a kernel panic. > >>> > >>>This is useful to allow the user to assign a regular trigger > >>>to a given LED, and still blink that LED on a kernel panic. > >>> > >>>Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar> > >> > >> > >>> drivers/leds/led-triggers.c | 52 +++++++++++++++++++++++++++++++++++++++++++++ > >>> include/linux/leds.h | 1 + > >> > >>Could we get this out of the core? I'm pretty sure most users are not > >>interested... > > Good point. Dunno. Perhaps we can have something like struct led *panic_led, which architecture can set, and then some helper that would blink the panic led...? Should be smaller than this and will only be compiled on platforms where it makes sense. On x86 we already have such support... > >Thinking about it some more.... > > > >This is not really a trigger. This is very special. Maybe hard-coded > >handling, like we do for keyboard leds on x86 would be suitable? > > Could you please spot the piece of code you have on mind? drivers/input/serio/i8042.c: * i8042_panic_blink() will turn the keyboard LEDs on or off and is called Pavel
diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c index 2181581795d3..f5c9d7c4d181 100644 --- a/drivers/leds/led-triggers.c +++ b/drivers/leds/led-triggers.c @@ -148,6 +148,43 @@ void led_trigger_remove(struct led_classdev *led_cdev) } EXPORT_SYMBOL_GPL(led_trigger_remove); +/* + * This is a called in a special context by the atomic panic + * notifier. This means the trigger can be changed without + * worrying about locking. + */ +static void led_trigger_set_panic(struct led_classdev *led_cdev) +{ + struct led_trigger *trig; + + list_for_each_entry(trig, &trigger_list, next_trig) { + if (strcmp("panic", trig->name)) + continue; + if (led_cdev->trigger) + list_del(&led_cdev->trig_list); + list_add_tail(&led_cdev->trig_list, &trig->led_cdevs); + led_cdev->trigger = trig; + if (trig->activate) + trig->activate(led_cdev); + break; + } +} + +static int led_trigger_panic_notifier(struct notifier_block *nb, + unsigned long code, void *unused) +{ + struct led_classdev *led_cdev; + + list_for_each_entry(led_cdev, &leds_list, node) + if (led_cdev->flags & LED_BLINK_AT_PANIC) + led_trigger_set_panic(led_cdev); + return NOTIFY_DONE; +} + +static struct notifier_block led_trigger_panic_nb = { + .notifier_call = led_trigger_panic_notifier, +}; + void led_trigger_set_default(struct led_classdev *led_cdev) { struct led_trigger *trig; @@ -356,6 +393,21 @@ void led_trigger_unregister_simple(struct led_trigger *trig) } EXPORT_SYMBOL_GPL(led_trigger_unregister_simple); +static int __init leds_trigger_init(void) +{ + atomic_notifier_chain_register(&panic_notifier_list, + &led_trigger_panic_nb); + return 0; +} + +static void __exit leds_trigger_exit(void) +{ + atomic_notifier_chain_unregister(&panic_notifier_list, + &led_trigger_panic_nb); +} +module_init(leds_trigger_init); +module_exit(leds_trigger_exit); + MODULE_AUTHOR("Richard Purdie"); MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("LED Triggers Core"); diff --git a/include/linux/leds.h b/include/linux/leds.h index f203a8f89d30..7f1428bb1e69 100644 --- a/include/linux/leds.h +++ b/include/linux/leds.h @@ -50,6 +50,7 @@ struct led_classdev { #define LED_SYSFS_DISABLE (1 << 22) #define LED_DEV_CAP_FLASH (1 << 23) #define LED_HW_PLUGGABLE (1 << 24) +#define LED_BLINK_AT_PANIC (1 << 25) /* Set LED brightness level * Must not sleep. Use brightness_set_blocking for drivers
This commit adds a new led_cdev flag LED_BLINK_AT_PANIC, which allows to mark a specific LED to be switched to the "panic" trigger, on a kernel panic. This is useful to allow the user to assign a regular trigger to a given LED, and still blink that LED on a kernel panic. Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar> --- drivers/leds/led-triggers.c | 52 +++++++++++++++++++++++++++++++++++++++++++++ include/linux/leds.h | 1 + 2 files changed, 53 insertions(+)