leds: ledtrig-timer trigger_data allocation fix

PATCH In review Shuah Khan 2 participants 7 messages Apr 17, 2012 – Apr 20, 2012 LED

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Shuah Khan

author

2012-04-17 23:05 UTC #0 lore raw

PATCH 1/1 leds: ledtrig-timer trigger_data allocation fix

ledtrig-timer doesn't allocate memory for trigger_data and assigns (void *)1 to save state. Fixed it to allocate int instead. Please note that non-null trigger_data is used to key off of to do proper cleanup in deactivation routine and not used during the life of the trigger itself.

Quoted 1 line

From 9f7a6fc40ce7322145b6adea8771c8d547c151ec Mon Sep 17 00:00:00 2001

From: Shuah Khan <[email protected]>
Date: Tue, 17 Apr 2012 16:04:56 -0600
Subject: [PATCH] leds: ledtrig-timer trigger_data allocation fix

Signed-off-by Shuah Khan <[email protected]>

---
 drivers/leds/ledtrig-timer.c |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

drivers/leds/ledtrig-timer.c +7 -1

index b32d5ea..64b6915 100644
@@ -16,6 +16,7 @@
 #include <linux/init.h>
 #include <linux/device.h>
 #include <linux/ctype.h>
+#include <linux/slab.h>
 #include <linux/leds.h>
 #include "leds.h"

@@ -88,10 +89,14 @@ static void timer_trig_activate(struct led_classdev *led_cdev)
 	led_blink_set(led_cdev, &led_cdev->blink_delay_on,
 		      &led_cdev->blink_delay_off);
 
-	led_cdev->trigger_data = (void *)1;
+	led_cdev->trigger_data = kzalloc(sizeof(int), GFP_KERNEL);
+	if (!led_cdev->trigger_data)
+		goto err_out_delayoff;
 
 	return;
 
+err_out_delayoff:
+	device_remove_file(led_cdev->dev, &dev_attr_delay_off);
 err_out_delayon:
 	device_remove_file(led_cdev->dev, &dev_attr_delay_on);
 }

@@ -101,6 +106,7 @@ static void timer_trig_deactivate(struct led_classdev *led_cdev)
 	if (led_cdev->trigger_data) {
 		device_remove_file(led_cdev->dev, &dev_attr_delay_on);
 		device_remove_file(led_cdev->dev, &dev_attr_delay_off);
+		kfree(led_cdev->trigger_data);
 	}
 
 	/* Stop blinking */

Signature · 1 line

1.7.5.4

Andrew Morton

2012-04-17 23:12 UTC #1 lore raw

Quoted 5 lines · On Tue, 17 Apr 2012 17:05:11 -0600 Shuah Khan <[email protected]> wrote:

ledtrig-timer doesn't allocate memory for trigger_data and assigns (void *)1 to save state. Fixed it to allocate int instead. Please note that non-null trigger_data is used to key off of to do proper cleanup in deactivation routine and not used during the life of the trigger itself.

In that case, overloading the value of ->trigger_data in this fashion is inappropriate and a new field should be added to led_classdev for this purpose.

Review

Quoted 2 lines

(quoted diff) +1 -1

-	led_cdev->trigger_data = (void *)1;
+	led_cdev->trigger_data = kzalloc(sizeof(int), GFP_KERNEL);

But that's better than what we have now.

It does require a comment though:

drivers/leds/ledtrig-timer.c renamed from drivers/leds/ledtrig-timer.c~leds-ledtrig-timer-trigger_data-allocation-fix-fix +5 -0

@@ -89,6 +89,11 @@ static void timer_trig_activate(struct l
 	led_blink_set(led_cdev, &led_cdev->blink_delay_on,
 		      &led_cdev->blink_delay_off);
 
+	/*
+	 * Place a dummy allocation at ->trigger_data so that
+	 * timer_trig_deactivate() cleans up correctly.  This data is never
+	 * actually used.
+	 */
 	led_cdev->trigger_data = kzalloc(sizeof(int), GFP_KERNEL);
 	if (!led_cdev->trigger_data)
 		goto err_out_delayoff;

Shuah Khan

author

2012-04-20 03:48 UTC #2 lore raw

PATCH 1/1 leds: add new field to led_classdev struct to save activation state

This patch adds a new field to led_classdev to save activattion state after activate routine is successful. This saved state is used in deactivate routine to do cleanup such as removing device files, and free memory allocated during activation. Currently trigger_data not being null is used for this purpose.

Existing triggers will need changes to use this new field.

Quoted 1 line

From 3765101a5ffe32edd68a71bafca2d6d262cf2399 Mon Sep 17 00:00:00 2001

From: Shuah Khan <[email protected]>
Date: Thu, 19 Apr 2012 20:44:15 -0600
Subject: [PATCH] leds: add new field to led_classdev struct to save
activation state

Signed-off-by Shuah Khan <[email protected]>

---
 include/linux/leds.h |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

include/linux/leds.h +2 -0

index 5884def..39eee41 100644
@@ -73,6 +73,8 @@ struct led_classdev {
 	struct led_trigger	*trigger;
 	struct list_head	 trig_list;
 	void			*trigger_data;
+	/* true if activated - deactivate routine uses it to do cleanup */
+	bool			activated;
 #endif
 };

Signature · 1 line

1.7.5.4

Shuah Khan

author

2012-04-20 20:14 UTC #3 lore raw

PATCH 1/1 leds: change existing triggers to use activated flag

Changed existing triggers backlight, gpio, and heartbeat to use activated flag to set activate successful status in their activate routines and check it in their deactivate routines to do cleanup.

Quoted 1 line

From c0afeb736a5cb23d4212ac5900e2b514d0e75e90 Mon Sep 17 00:00:00 2001

From: Shuah Khan <[email protected]>
Date: Fri, 20 Apr 2012 12:41:00 -0600
Subject: [PATCH] leds: change existing triggers to use activated flag

Signed-off-by Shuah Khan <[email protected]>

---
 drivers/leds/ledtrig-backlight.c |    4 +++-
 drivers/leds/ledtrig-gpio.c      |    4 +++-
 drivers/leds/ledtrig-heartbeat.c |    4 +++-
 3 files changed, 9 insertions(+), 3 deletions(-)

drivers/leds/ledtrig-backlight.c +3 -1

index 2b513a2..e272686 100644
@@ -120,6 +120,7 @@ static void bl_trig_activate(struct led_classdev *led)
 	ret = fb_register_client(&n->notifier);
 	if (ret)
 		dev_err(led->dev, "unable to register backlight trigger\n");
+	led->activated = true;
 
 	return;

@@ -133,10 +134,11 @@ static void bl_trig_deactivate(struct led_classdev *led)
 	struct bl_trig_notifier *n =
 		(struct bl_trig_notifier *) led->trigger_data;
 
-	if (n) {
+	if (led->activated) {
 		device_remove_file(led->dev, &dev_attr_inverted);
 		fb_unregister_client(&n->notifier);
 		kfree(n);
+		led->activated = false;
 	}
 }

drivers/leds/ledtrig-gpio.c +3 -1

index ecc4bf3..f057c10 100644
@@ -200,6 +200,7 @@ static void gpio_trig_activate(struct led_classdev *led)
 	gpio_data->led = led;
 	led->trigger_data = gpio_data;
 	INIT_WORK(&gpio_data->work, gpio_trig_work);
+	led->activated = true;
 
 	return;

@@ -217,7 +218,7 @@ static void gpio_trig_deactivate(struct led_classdev *led)
 {
 	struct gpio_trig_data *gpio_data = led->trigger_data;
 
-	if (gpio_data) {
+	if (led->activated) {
 		device_remove_file(led->dev, &dev_attr_gpio);
 		device_remove_file(led->dev, &dev_attr_inverted);
 		device_remove_file(led->dev, &dev_attr_desired_brightness);

@@ -225,6 +226,7 @@ static void gpio_trig_deactivate(struct led_classdev *led)
 		if (gpio_data->gpio != 0)
 			free_irq(gpio_to_irq(gpio_data->gpio), led);
 		kfree(gpio_data);
+		led->activated = false;
 	}
 }

drivers/leds/ledtrig-heartbeat.c +3 -1

index 759c0bb..1aacf4c 100644
@@ -83,15 +83,17 @@ static void heartbeat_trig_activate(struct led_classdev *led_cdev)
 		    led_heartbeat_function, (unsigned long) led_cdev);
 	heartbeat_data->phase = 0;
 	led_heartbeat_function(heartbeat_data->timer.data);
+	led_cdev->activated = true;
 }
 
 static void heartbeat_trig_deactivate(struct led_classdev *led_cdev)
 {
 	struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data;
 
-	if (heartbeat_data) {
+	if (led_cdev->activated) {
 		del_timer_sync(&heartbeat_data->timer);
 		kfree(heartbeat_data);
+		led_cdev->activated = false;
 	}
 }

Signature · 1 line

1.7.5.4

Shuah Khan

author

2012-04-20 20:17 UTC #4 lore raw

PATCH 1/1 leds: change ledtrig-timer to use activated flag

In reply to Shuah Khan

Changed existing timer trigger to use activated flag to set activate successful status in activate routine and check it in deactivate routine to do cleanup.

Quoted 1 line

From 4b7baef37d25b5ba5ed9f561375157e2a717e28f Mon Sep 17 00:00:00 2001

From: Shuah Khan <[email protected]>
Date: Fri, 20 Apr 2012 13:07:20 -0600
Subject: [PATCH] leds: change ledtrig-timer to use activated flag

Signed-off-by Shuah Khan <[email protected]>

---
 drivers/leds/ledtrig-timer.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

drivers/leds/ledtrig-timer.c +3 -3

index 328c64c..e20d1db 100644
@@ -95,8 +95,7 @@ static void timer_trig_activate(struct led_classdev *led_cdev)
 
 	led_blink_set(led_cdev, &led_cdev->blink_delay_on,
 		      &led_cdev->blink_delay_off);
-
-	led_cdev->trigger_data = (void *)1;
+	led_cdev->activated = true;
 
 	return;

@@ -106,9 +105,10 @@ err_out_delayon:
 
 static void timer_trig_deactivate(struct led_classdev *led_cdev)
 {
-	if (led_cdev->trigger_data) {
+	if (led_cdev->activated) {
 		device_remove_file(led_cdev->dev, &dev_attr_delay_on);
 		device_remove_file(led_cdev->dev, &dev_attr_delay_off);
+		led_cdev->activated = false;
 	}
 
 	/* Stop blinking */

Signature · 1 line

1.7.5.4

Andrew Morton

2012-04-20 21:04 UTC #5 lore raw

Re: [PATCH] leds: change ledtrig-timer to use activated flag

Quoted 3 lines · On Fri, 20 Apr 2012 14:17:25 -0600 Shuah Khan <[email protected]> wrote:

Changed existing timer trigger to use activated flag to set activate successful status in activate routine and check it in deactivate routine to do cleanup.

Thanks. I dropped "leds: ledtrig-timer trigger_data allocation fix" as these patches conflict, and I believe that "leds: ledtrig-timer trigger_data allocation fix" is no longer needed?

Shuah Khan

author

2012-04-20 21:16 UTC #6 lore raw

Re: [PATCH] leds: change ledtrig-timer to use activated flag

Quoted 11 lines · Andrew Morton

Quoted 3 lines · On Fri, 20 Apr 2012 14:17:25 -0600 Shuah Khan <[email protected]> wrote:
Changed existing timer trigger to use activated flag to set activate successful status in activate routine and check it in deactivate routine to do cleanup.
Thanks. I dropped "leds: ledtrig-timer trigger_data allocation fix" as these patches conflict, and I believe that "leds: ledtrig-timer trigger_data allocation fix" is no longer needed?

That is correct. It is no longer needed.

-- Shuah

Quoted 6 lines

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