Re: [PATCH v3 1/3] leds: triggers: Allow to switch the trigger to "panic" on a kernel panic

2016-05-06 Thread Ezequiel Garcia 
On 6 May 2016 at 06:03, Jacek Anaszewski  wrote:
> On 04/29/2016 09:20 AM, Jacek Anaszewski wrote:
>>
>> Hi Ezequiel,
>>
>> Thanks for the update. It's indeed reasonable to have all the
>> switching infrastructure in ledtrig-panic.c.
>>
>> I've noticed two minor issues below.
>
>
> Since the merge window is imminent, I've addressed those issues by
> myself and applied the patch set to the for-next branch
> of linux-leds.git.
>

Thanks a lot for taking care of this, Jacek!
-- 
Ezequiel García, VanguardiaSur
www.vanguardiasur.com.ar

Re: [PATCH v3 1/3] leds: triggers: Allow to switch the trigger to "panic" on a kernel panic

2016-05-06 Thread Ezequiel Garcia 
On 6 May 2016 at 06:03, Jacek Anaszewski  wrote:
> On 04/29/2016 09:20 AM, Jacek Anaszewski wrote:
>>
>> Hi Ezequiel,
>>
>> Thanks for the update. It's indeed reasonable to have all the
>> switching infrastructure in ledtrig-panic.c.
>>
>> I've noticed two minor issues below.
>
>
> Since the merge window is imminent, I've addressed those issues by
> myself and applied the patch set to the for-next branch
> of linux-leds.git.
>

Thanks a lot for taking care of this, Jacek!
-- 
Ezequiel García, VanguardiaSur
www.vanguardiasur.com.ar

Re: [PATCH v3 1/3] leds: triggers: Allow to switch the trigger to "panic" on a kernel panic

2016-05-06 Thread Jacek Anaszewski 

On 04/29/2016 09:20 AM, Jacek Anaszewski wrote:

Hi Ezequiel,

Thanks for the update. It's indeed reasonable to have all the
switching infrastructure in ledtrig-panic.c.

I've noticed two minor issues below.


Since the merge window is imminent, I've addressed those issues by
myself and applied the patch set to the for-next branch
of linux-leds.git.

Thanks,
Jacek Anaszewski


On 04/29/2016 12:03 AM, Ezequiel Garcia wrote:

This commit adds a new led_cdev flag LED_PANIC_INDICATOR, 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 
---
  drivers/leds/led-triggers.c  |  2 +-
  drivers/leds/leds.h  |  1 +
  drivers/leds/trigger/Kconfig |  3 +++
  drivers/leds/trigger/ledtrig-panic.c | 47

  include/linux/leds.h |  1 +
  5 files changed, 53 insertions(+), 1 deletion(-)

diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c
index 2181581795d3..55fa65e1ae03 100644
--- a/drivers/leds/led-triggers.c
+++ b/drivers/leds/led-triggers.c
@@ -26,7 +26,7 @@
   * Nests outside led_cdev->trigger_lock
   */
  static DECLARE_RWSEM(triggers_list_lock);
-static LIST_HEAD(trigger_list);
+LIST_HEAD(trigger_list);

   /* Used by LED Class */

diff --git a/drivers/leds/leds.h b/drivers/leds/leds.h
index db3f20da7221..7d38e6b9a740 100644
--- a/drivers/leds/leds.h
+++ b/drivers/leds/leds.h
@@ -30,5 +30,6 @@ void led_set_brightness_nosleep(struct led_classdev
*led_cdev,

  extern struct rw_semaphore leds_list_lock;
  extern struct list_head leds_list;
+extern struct list_head trigger_list;

  #endif/* __LEDS_H_INCLUDED */
diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig
index beac8c31c51b..4e4521c9072a 100644
--- a/drivers/leds/trigger/Kconfig
+++ b/drivers/leds/trigger/Kconfig
@@ -121,6 +121,9 @@ config LEDS_TRIGGER_PANIC
  depends on LEDS_TRIGGERS
  help
This allows LEDs to be configured to blink on a kernel panic.
+  Enabling this option will allow to mark certain LEDs as
'panic-indicators',


s/"panic-indicators"/panic indicators/

I understand that you referred here to the DT property name, but this
is not obvious at first glance, and it is an implementation detail.


+  allowing to blink them on a kernel panic, even if they are set to
+  a different trigger.
If unsure, say Y.

  endif # LEDS_TRIGGERS
diff --git a/drivers/leds/trigger/ b/drivers/leds/trigger/ledtrig-panic.c
index 627b350c5ec3..3e447bd2064a 100644
--- a/drivers/leds/trigger/ledtrig-panic.c
+++ b/drivers/leds/trigger/ledtrig-panic.c
@@ -11,10 +11,54 @@

  #include 
  #include 
+#include 
  #include 
+#include "../leds.h"

  static struct led_trigger *trigger;

+/*
+ * This is a called in a special context by the atomic panic


s/is a/is/


+ * 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, _list, next_trig) {
+if (strcmp("panic", trig->name))
+continue;
+if (led_cdev->trigger)
+list_del(_cdev->trig_list);
+list_add_tail(_cdev->trig_list, >led_cdevs);
+
+/* Avoid the delayed blink path */
+led_cdev->blink_delay_on = 0;
+led_cdev->blink_delay_off = 0;
+
+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, _list, node)
+if (led_cdev->flags & LED_PANIC_INDICATOR)
+led_trigger_set_panic(led_cdev);
+return NOTIFY_DONE;
+}
+
+static struct notifier_block led_trigger_panic_nb = {
+.notifier_call = led_trigger_panic_notifier,
+};
+
  static long led_panic_blink(int state)
  {
  led_trigger_event(trigger, state ? LED_FULL : LED_OFF);
@@ -23,6 +67,9 @@ static long led_panic_blink(int state)

  static int __init ledtrig_panic_init(void)
  {
+atomic_notifier_chain_register(_notifier_list,
+   _trigger_panic_nb);
+
  led_trigger_register_simple("panic", );
  panic_blink = led_panic_blink;
  return 0;
diff --git a/include/linux/leds.h b/include/linux/leds.h
index 19eb10278bea..7e9fb00e15e8 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_PANIC_INDICATOR(1 << 25)

  /* Set LED brightness level
   * Must not sleep.

Re: [PATCH v3 1/3] leds: triggers: Allow to switch the trigger to "panic" on a kernel panic

2016-05-06 Thread Jacek Anaszewski 

On 04/29/2016 09:20 AM, Jacek Anaszewski wrote:

Hi Ezequiel,

Thanks for the update. It's indeed reasonable to have all the
switching infrastructure in ledtrig-panic.c.

I've noticed two minor issues below.


Since the merge window is imminent, I've addressed those issues by
myself and applied the patch set to the for-next branch
of linux-leds.git.

Thanks,
Jacek Anaszewski


On 04/29/2016 12:03 AM, Ezequiel Garcia wrote:

This commit adds a new led_cdev flag LED_PANIC_INDICATOR, 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 
---
  drivers/leds/led-triggers.c  |  2 +-
  drivers/leds/leds.h  |  1 +
  drivers/leds/trigger/Kconfig |  3 +++
  drivers/leds/trigger/ledtrig-panic.c | 47

  include/linux/leds.h |  1 +
  5 files changed, 53 insertions(+), 1 deletion(-)

diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c
index 2181581795d3..55fa65e1ae03 100644
--- a/drivers/leds/led-triggers.c
+++ b/drivers/leds/led-triggers.c
@@ -26,7 +26,7 @@
   * Nests outside led_cdev->trigger_lock
   */
  static DECLARE_RWSEM(triggers_list_lock);
-static LIST_HEAD(trigger_list);
+LIST_HEAD(trigger_list);

   /* Used by LED Class */

diff --git a/drivers/leds/leds.h b/drivers/leds/leds.h
index db3f20da7221..7d38e6b9a740 100644
--- a/drivers/leds/leds.h
+++ b/drivers/leds/leds.h
@@ -30,5 +30,6 @@ void led_set_brightness_nosleep(struct led_classdev
*led_cdev,

  extern struct rw_semaphore leds_list_lock;
  extern struct list_head leds_list;
+extern struct list_head trigger_list;

  #endif/* __LEDS_H_INCLUDED */
diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig
index beac8c31c51b..4e4521c9072a 100644
--- a/drivers/leds/trigger/Kconfig
+++ b/drivers/leds/trigger/Kconfig
@@ -121,6 +121,9 @@ config LEDS_TRIGGER_PANIC
  depends on LEDS_TRIGGERS
  help
This allows LEDs to be configured to blink on a kernel panic.
+  Enabling this option will allow to mark certain LEDs as
'panic-indicators',


s/"panic-indicators"/panic indicators/

I understand that you referred here to the DT property name, but this
is not obvious at first glance, and it is an implementation detail.


+  allowing to blink them on a kernel panic, even if they are set to
+  a different trigger.
If unsure, say Y.

  endif # LEDS_TRIGGERS
diff --git a/drivers/leds/trigger/ b/drivers/leds/trigger/ledtrig-panic.c
index 627b350c5ec3..3e447bd2064a 100644
--- a/drivers/leds/trigger/ledtrig-panic.c
+++ b/drivers/leds/trigger/ledtrig-panic.c
@@ -11,10 +11,54 @@

  #include 
  #include 
+#include 
  #include 
+#include "../leds.h"

  static struct led_trigger *trigger;

+/*
+ * This is a called in a special context by the atomic panic


s/is a/is/


+ * 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, _list, next_trig) {
+if (strcmp("panic", trig->name))
+continue;
+if (led_cdev->trigger)
+list_del(_cdev->trig_list);
+list_add_tail(_cdev->trig_list, >led_cdevs);
+
+/* Avoid the delayed blink path */
+led_cdev->blink_delay_on = 0;
+led_cdev->blink_delay_off = 0;
+
+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, _list, node)
+if (led_cdev->flags & LED_PANIC_INDICATOR)
+led_trigger_set_panic(led_cdev);
+return NOTIFY_DONE;
+}
+
+static struct notifier_block led_trigger_panic_nb = {
+.notifier_call = led_trigger_panic_notifier,
+};
+
  static long led_panic_blink(int state)
  {
  led_trigger_event(trigger, state ? LED_FULL : LED_OFF);
@@ -23,6 +67,9 @@ static long led_panic_blink(int state)

  static int __init ledtrig_panic_init(void)
  {
+atomic_notifier_chain_register(_notifier_list,
+   _trigger_panic_nb);
+
  led_trigger_register_simple("panic", );
  panic_blink = led_panic_blink;
  return 0;
diff --git a/include/linux/leds.h b/include/linux/leds.h
index 19eb10278bea..7e9fb00e15e8 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_PANIC_INDICATOR(1 << 25)

  /* Set LED brightness level
   * Must not sleep. Use brightness_set_blocking for

Re: [PATCH v3 1/3] leds: triggers: Allow to switch the trigger to "panic" on a kernel panic

2016-04-29 Thread Jacek Anaszewski 

Hi Ezequiel,

Thanks for the update. It's indeed reasonable to have all the
switching infrastructure in ledtrig-panic.c.

I've noticed two minor issues below.

On 04/29/2016 12:03 AM, Ezequiel Garcia wrote:

This commit adds a new led_cdev flag LED_PANIC_INDICATOR, 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 
---
  drivers/leds/led-triggers.c  |  2 +-
  drivers/leds/leds.h  |  1 +
  drivers/leds/trigger/Kconfig |  3 +++
  drivers/leds/trigger/ledtrig-panic.c | 47 
  include/linux/leds.h |  1 +
  5 files changed, 53 insertions(+), 1 deletion(-)

diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c
index 2181581795d3..55fa65e1ae03 100644
--- a/drivers/leds/led-triggers.c
+++ b/drivers/leds/led-triggers.c
@@ -26,7 +26,7 @@
   * Nests outside led_cdev->trigger_lock
   */
  static DECLARE_RWSEM(triggers_list_lock);
-static LIST_HEAD(trigger_list);
+LIST_HEAD(trigger_list);

   /* Used by LED Class */

diff --git a/drivers/leds/leds.h b/drivers/leds/leds.h
index db3f20da7221..7d38e6b9a740 100644
--- a/drivers/leds/leds.h
+++ b/drivers/leds/leds.h
@@ -30,5 +30,6 @@ void led_set_brightness_nosleep(struct led_classdev *led_cdev,

  extern struct rw_semaphore leds_list_lock;
  extern struct list_head leds_list;
+extern struct list_head trigger_list;

  #endif/* __LEDS_H_INCLUDED */
diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig
index beac8c31c51b..4e4521c9072a 100644
--- a/drivers/leds/trigger/Kconfig
+++ b/drivers/leds/trigger/Kconfig
@@ -121,6 +121,9 @@ config LEDS_TRIGGER_PANIC
depends on LEDS_TRIGGERS
help
  This allows LEDs to be configured to blink on a kernel panic.
+ Enabling this option will allow to mark certain LEDs as 
'panic-indicators',


s/"panic-indicators"/panic indicators/

I understand that you referred here to the DT property name, but this
is not obvious at first glance, and it is an implementation detail.


+ allowing to blink them on a kernel panic, even if they are set to
+ a different trigger.
  If unsure, say Y.

  endif # LEDS_TRIGGERS
diff --git a/drivers/leds/trigger/ b/drivers/leds/trigger/ledtrig-panic.c
index 627b350c5ec3..3e447bd2064a 100644
--- a/drivers/leds/trigger/ledtrig-panic.c
+++ b/drivers/leds/trigger/ledtrig-panic.c
@@ -11,10 +11,54 @@

  #include 
  #include 
+#include 
  #include 
+#include "../leds.h"

  static struct led_trigger *trigger;

+/*
+ * This is a called in a special context by the atomic panic


s/is a/is/


+ * 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, _list, next_trig) {
+   if (strcmp("panic", trig->name))
+   continue;
+   if (led_cdev->trigger)
+   list_del(_cdev->trig_list);
+   list_add_tail(_cdev->trig_list, >led_cdevs);
+
+   /* Avoid the delayed blink path */
+   led_cdev->blink_delay_on = 0;
+   led_cdev->blink_delay_off = 0;
+
+   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, _list, node)
+   if (led_cdev->flags & LED_PANIC_INDICATOR)
+   led_trigger_set_panic(led_cdev);
+   return NOTIFY_DONE;
+}
+
+static struct notifier_block led_trigger_panic_nb = {
+   .notifier_call = led_trigger_panic_notifier,
+};
+
  static long led_panic_blink(int state)
  {
led_trigger_event(trigger, state ? LED_FULL : LED_OFF);
@@ -23,6 +67,9 @@ static long led_panic_blink(int state)

  static int __init ledtrig_panic_init(void)
  {
+   atomic_notifier_chain_register(_notifier_list,
+  _trigger_panic_nb);
+
led_trigger_register_simple("panic", );
panic_blink = led_panic_blink;
return 0;
diff --git a/include/linux/leds.h b/include/linux/leds.h
index 19eb10278bea..7e9fb00e15e8 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_PANIC_INDICATOR(1 << 25)

/* Set LED brightness level
 * Must not sleep. Use

Re: [PATCH v3 1/3] leds: triggers: Allow to switch the trigger to "panic" on a kernel panic

2016-04-29 Thread Jacek Anaszewski 

Hi Ezequiel,

Thanks for the update. It's indeed reasonable to have all the
switching infrastructure in ledtrig-panic.c.

I've noticed two minor issues below.

On 04/29/2016 12:03 AM, Ezequiel Garcia wrote:

This commit adds a new led_cdev flag LED_PANIC_INDICATOR, 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 
---
  drivers/leds/led-triggers.c  |  2 +-
  drivers/leds/leds.h  |  1 +
  drivers/leds/trigger/Kconfig |  3 +++
  drivers/leds/trigger/ledtrig-panic.c | 47 
  include/linux/leds.h |  1 +
  5 files changed, 53 insertions(+), 1 deletion(-)

diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c
index 2181581795d3..55fa65e1ae03 100644
--- a/drivers/leds/led-triggers.c
+++ b/drivers/leds/led-triggers.c
@@ -26,7 +26,7 @@
   * Nests outside led_cdev->trigger_lock
   */
  static DECLARE_RWSEM(triggers_list_lock);
-static LIST_HEAD(trigger_list);
+LIST_HEAD(trigger_list);

   /* Used by LED Class */

diff --git a/drivers/leds/leds.h b/drivers/leds/leds.h
index db3f20da7221..7d38e6b9a740 100644
--- a/drivers/leds/leds.h
+++ b/drivers/leds/leds.h
@@ -30,5 +30,6 @@ void led_set_brightness_nosleep(struct led_classdev *led_cdev,

  extern struct rw_semaphore leds_list_lock;
  extern struct list_head leds_list;
+extern struct list_head trigger_list;

  #endif/* __LEDS_H_INCLUDED */
diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig
index beac8c31c51b..4e4521c9072a 100644
--- a/drivers/leds/trigger/Kconfig
+++ b/drivers/leds/trigger/Kconfig
@@ -121,6 +121,9 @@ config LEDS_TRIGGER_PANIC
depends on LEDS_TRIGGERS
help
  This allows LEDs to be configured to blink on a kernel panic.
+ Enabling this option will allow to mark certain LEDs as 
'panic-indicators',


s/"panic-indicators"/panic indicators/

I understand that you referred here to the DT property name, but this
is not obvious at first glance, and it is an implementation detail.


+ allowing to blink them on a kernel panic, even if they are set to
+ a different trigger.
  If unsure, say Y.

  endif # LEDS_TRIGGERS
diff --git a/drivers/leds/trigger/ b/drivers/leds/trigger/ledtrig-panic.c
index 627b350c5ec3..3e447bd2064a 100644
--- a/drivers/leds/trigger/ledtrig-panic.c
+++ b/drivers/leds/trigger/ledtrig-panic.c
@@ -11,10 +11,54 @@

  #include 
  #include 
+#include 
  #include 
+#include "../leds.h"

  static struct led_trigger *trigger;

+/*
+ * This is a called in a special context by the atomic panic


s/is a/is/


+ * 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, _list, next_trig) {
+   if (strcmp("panic", trig->name))
+   continue;
+   if (led_cdev->trigger)
+   list_del(_cdev->trig_list);
+   list_add_tail(_cdev->trig_list, >led_cdevs);
+
+   /* Avoid the delayed blink path */
+   led_cdev->blink_delay_on = 0;
+   led_cdev->blink_delay_off = 0;
+
+   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, _list, node)
+   if (led_cdev->flags & LED_PANIC_INDICATOR)
+   led_trigger_set_panic(led_cdev);
+   return NOTIFY_DONE;
+}
+
+static struct notifier_block led_trigger_panic_nb = {
+   .notifier_call = led_trigger_panic_notifier,
+};
+
  static long led_panic_blink(int state)
  {
led_trigger_event(trigger, state ? LED_FULL : LED_OFF);
@@ -23,6 +67,9 @@ static long led_panic_blink(int state)

  static int __init ledtrig_panic_init(void)
  {
+   atomic_notifier_chain_register(_notifier_list,
+  _trigger_panic_nb);
+
led_trigger_register_simple("panic", );
panic_blink = led_panic_blink;
return 0;
diff --git a/include/linux/leds.h b/include/linux/leds.h
index 19eb10278bea..7e9fb00e15e8 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_PANIC_INDICATOR(1 << 25)

/* Set LED brightness level
 * Must not sleep. Use brightness_set_blocking for drivers




--

[PATCH v3 1/3] leds: triggers: Allow to switch the trigger to "panic" on a kernel panic

2016-04-28 Thread Ezequiel Garcia 
This commit adds a new led_cdev flag LED_PANIC_INDICATOR, 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 
---
 drivers/leds/led-triggers.c  |  2 +-
 drivers/leds/leds.h  |  1 +
 drivers/leds/trigger/Kconfig |  3 +++
 drivers/leds/trigger/ledtrig-panic.c | 47 
 include/linux/leds.h |  1 +
 5 files changed, 53 insertions(+), 1 deletion(-)

diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c
index 2181581795d3..55fa65e1ae03 100644
--- a/drivers/leds/led-triggers.c
+++ b/drivers/leds/led-triggers.c
@@ -26,7 +26,7 @@
  * Nests outside led_cdev->trigger_lock
  */
 static DECLARE_RWSEM(triggers_list_lock);
-static LIST_HEAD(trigger_list);
+LIST_HEAD(trigger_list);
 
  /* Used by LED Class */
 
diff --git a/drivers/leds/leds.h b/drivers/leds/leds.h
index db3f20da7221..7d38e6b9a740 100644
--- a/drivers/leds/leds.h
+++ b/drivers/leds/leds.h
@@ -30,5 +30,6 @@ void led_set_brightness_nosleep(struct led_classdev *led_cdev,
 
 extern struct rw_semaphore leds_list_lock;
 extern struct list_head leds_list;
+extern struct list_head trigger_list;
 
 #endif /* __LEDS_H_INCLUDED */
diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig
index beac8c31c51b..4e4521c9072a 100644
--- a/drivers/leds/trigger/Kconfig
+++ b/drivers/leds/trigger/Kconfig
@@ -121,6 +121,9 @@ config LEDS_TRIGGER_PANIC
depends on LEDS_TRIGGERS
help
  This allows LEDs to be configured to blink on a kernel panic.
+ Enabling this option will allow to mark certain LEDs as 
'panic-indicators',
+ allowing to blink them on a kernel panic, even if they are set to
+ a different trigger.
  If unsure, say Y.
 
 endif # LEDS_TRIGGERS
diff --git a/drivers/leds/trigger/ledtrig-panic.c 
b/drivers/leds/trigger/ledtrig-panic.c
index 627b350c5ec3..3e447bd2064a 100644
--- a/drivers/leds/trigger/ledtrig-panic.c
+++ b/drivers/leds/trigger/ledtrig-panic.c
@@ -11,10 +11,54 @@
 
 #include 
 #include 
+#include 
 #include 
+#include "../leds.h"
 
 static struct led_trigger *trigger;
 
+/*
+ * 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, _list, next_trig) {
+   if (strcmp("panic", trig->name))
+   continue;
+   if (led_cdev->trigger)
+   list_del(_cdev->trig_list);
+   list_add_tail(_cdev->trig_list, >led_cdevs);
+
+   /* Avoid the delayed blink path */
+   led_cdev->blink_delay_on = 0;
+   led_cdev->blink_delay_off = 0;
+
+   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, _list, node)
+   if (led_cdev->flags & LED_PANIC_INDICATOR)
+   led_trigger_set_panic(led_cdev);
+   return NOTIFY_DONE;
+}
+
+static struct notifier_block led_trigger_panic_nb = {
+   .notifier_call = led_trigger_panic_notifier,
+};
+
 static long led_panic_blink(int state)
 {
led_trigger_event(trigger, state ? LED_FULL : LED_OFF);
@@ -23,6 +67,9 @@ static long led_panic_blink(int state)
 
 static int __init ledtrig_panic_init(void)
 {
+   atomic_notifier_chain_register(_notifier_list,
+  _trigger_panic_nb);
+
led_trigger_register_simple("panic", );
panic_blink = led_panic_blink;
return 0;
diff --git a/include/linux/leds.h b/include/linux/leds.h
index 19eb10278bea..7e9fb00e15e8 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_PANIC_INDICATOR(1 << 25)
 
/* Set LED brightness level
 * Must not sleep. Use brightness_set_blocking for drivers
-- 
2.7.0

[PATCH v3 1/3] leds: triggers: Allow to switch the trigger to "panic" on a kernel panic

2016-04-28 Thread Ezequiel Garcia 
This commit adds a new led_cdev flag LED_PANIC_INDICATOR, 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 
---
 drivers/leds/led-triggers.c  |  2 +-
 drivers/leds/leds.h  |  1 +
 drivers/leds/trigger/Kconfig |  3 +++
 drivers/leds/trigger/ledtrig-panic.c | 47 
 include/linux/leds.h |  1 +
 5 files changed, 53 insertions(+), 1 deletion(-)

diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c
index 2181581795d3..55fa65e1ae03 100644
--- a/drivers/leds/led-triggers.c
+++ b/drivers/leds/led-triggers.c
@@ -26,7 +26,7 @@
  * Nests outside led_cdev->trigger_lock
  */
 static DECLARE_RWSEM(triggers_list_lock);
-static LIST_HEAD(trigger_list);
+LIST_HEAD(trigger_list);
 
  /* Used by LED Class */
 
diff --git a/drivers/leds/leds.h b/drivers/leds/leds.h
index db3f20da7221..7d38e6b9a740 100644
--- a/drivers/leds/leds.h
+++ b/drivers/leds/leds.h
@@ -30,5 +30,6 @@ void led_set_brightness_nosleep(struct led_classdev *led_cdev,
 
 extern struct rw_semaphore leds_list_lock;
 extern struct list_head leds_list;
+extern struct list_head trigger_list;
 
 #endif /* __LEDS_H_INCLUDED */
diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig
index beac8c31c51b..4e4521c9072a 100644
--- a/drivers/leds/trigger/Kconfig
+++ b/drivers/leds/trigger/Kconfig
@@ -121,6 +121,9 @@ config LEDS_TRIGGER_PANIC
depends on LEDS_TRIGGERS
help
  This allows LEDs to be configured to blink on a kernel panic.
+ Enabling this option will allow to mark certain LEDs as 
'panic-indicators',
+ allowing to blink them on a kernel panic, even if they are set to
+ a different trigger.
  If unsure, say Y.
 
 endif # LEDS_TRIGGERS
diff --git a/drivers/leds/trigger/ledtrig-panic.c 
b/drivers/leds/trigger/ledtrig-panic.c
index 627b350c5ec3..3e447bd2064a 100644
--- a/drivers/leds/trigger/ledtrig-panic.c
+++ b/drivers/leds/trigger/ledtrig-panic.c
@@ -11,10 +11,54 @@
 
 #include 
 #include 
+#include 
 #include 
+#include "../leds.h"
 
 static struct led_trigger *trigger;
 
+/*
+ * 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, _list, next_trig) {
+   if (strcmp("panic", trig->name))
+   continue;
+   if (led_cdev->trigger)
+   list_del(_cdev->trig_list);
+   list_add_tail(_cdev->trig_list, >led_cdevs);
+
+   /* Avoid the delayed blink path */
+   led_cdev->blink_delay_on = 0;
+   led_cdev->blink_delay_off = 0;
+
+   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, _list, node)
+   if (led_cdev->flags & LED_PANIC_INDICATOR)
+   led_trigger_set_panic(led_cdev);
+   return NOTIFY_DONE;
+}
+
+static struct notifier_block led_trigger_panic_nb = {
+   .notifier_call = led_trigger_panic_notifier,
+};
+
 static long led_panic_blink(int state)
 {
led_trigger_event(trigger, state ? LED_FULL : LED_OFF);
@@ -23,6 +67,9 @@ static long led_panic_blink(int state)
 
 static int __init ledtrig_panic_init(void)
 {
+   atomic_notifier_chain_register(_notifier_list,
+  _trigger_panic_nb);
+
led_trigger_register_simple("panic", );
panic_blink = led_panic_blink;
return 0;
diff --git a/include/linux/leds.h b/include/linux/leds.h
index 19eb10278bea..7e9fb00e15e8 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_PANIC_INDICATOR(1 << 25)
 
/* Set LED brightness level
 * Must not sleep. Use brightness_set_blocking for drivers
-- 
2.7.0