Add support for HW offloading of the netdev trigger.

We need to change spinlock to mutex, because if spinlock is used, the
trigger_offload() method cannot sleep, which can happen for ethernet
PHYs.

We can change the spinlock to mutex because, according to Jacek:
  register_netdevice_notifier() registers raw notifier chain,
  whose callbacks are not called from atomic context and there are
  no restrictions on callbacks. See include/linux/notifier.h.

Move struct led_trigger_data into global include directory, into file
linux/ledtrig.h, so that drivers wanting to offload the trigger can
access its settings.

Also export the netdev_led_trigger variable and declare it in ledtrih.h
so that drivers may check whether the LED is set to this trigger.

Signed-off-by: Marek Behún <ka...@kernel.org>
---
 drivers/leds/trigger/ledtrig-netdev.c | 48 ++++++++++-----------------
 include/linux/ledtrig.h               | 40 ++++++++++++++++++++++
 2 files changed, 57 insertions(+), 31 deletions(-)
 create mode 100644 include/linux/ledtrig.h

diff --git a/drivers/leds/trigger/ledtrig-netdev.c 
b/drivers/leds/trigger/ledtrig-netdev.c
index 8f013b6df4fa..d4fa031d3a9e 100644
--- a/drivers/leds/trigger/ledtrig-netdev.c
+++ b/drivers/leds/trigger/ledtrig-netdev.c
@@ -10,17 +10,16 @@
 //  Copyright 2005-2006 Openedhand Ltd.
 //  Author: Richard Purdie <rpur...@openedhand.com>
 
-#include <linux/atomic.h>
 #include <linux/ctype.h>
 #include <linux/device.h>
 #include <linux/init.h>
 #include <linux/jiffies.h>
 #include <linux/kernel.h>
 #include <linux/leds.h>
+#include <linux/ledtrig.h>
 #include <linux/list.h>
 #include <linux/module.h>
 #include <linux/netdevice.h>
-#include <linux/spinlock.h>
 #include <linux/timer.h>
 #include "../leds.h"
 
@@ -36,26 +35,6 @@
  *
  */
 
-struct led_netdev_data {
-       spinlock_t lock;
-
-       struct delayed_work work;
-       struct notifier_block notifier;
-
-       struct led_classdev *led_cdev;
-       struct net_device *net_dev;
-
-       char device_name[IFNAMSIZ];
-       atomic_t interval;
-       unsigned int last_activity;
-
-       unsigned link:1;
-       unsigned tx:1;
-       unsigned rx:1;
-
-       unsigned linkup:1;
-};
-
 enum netdev_led_attr {
        NETDEV_ATTR_LINK,
        NETDEV_ATTR_TX,
@@ -73,6 +52,9 @@ static void set_baseline_state(struct led_netdev_data 
*trigger_data)
        if (!led_cdev->blink_brightness)
                led_cdev->blink_brightness = led_cdev->max_brightness;
 
+       if (!led_trigger_offload(led_cdev))
+               return;
+
        if (!trigger_data->linkup)
                led_set_brightness(led_cdev, LED_OFF);
        else {
@@ -96,9 +78,9 @@ static ssize_t device_name_show(struct device *dev,
        struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
        ssize_t len;
 
-       spin_lock_bh(&trigger_data->lock);
+       mutex_lock(&trigger_data->lock);
        len = sprintf(buf, "%s\n", trigger_data->device_name);
-       spin_unlock_bh(&trigger_data->lock);
+       mutex_unlock(&trigger_data->lock);
 
        return len;
 }
@@ -114,7 +96,7 @@ static ssize_t device_name_store(struct device *dev,
 
        cancel_delayed_work_sync(&trigger_data->work);
 
-       spin_lock_bh(&trigger_data->lock);
+       mutex_lock(&trigger_data->lock);
 
        if (trigger_data->net_dev) {
                dev_put(trigger_data->net_dev);
@@ -138,7 +120,7 @@ static ssize_t device_name_store(struct device *dev,
        trigger_data->last_activity = 0;
 
        set_baseline_state(trigger_data);
-       spin_unlock_bh(&trigger_data->lock);
+       mutex_unlock(&trigger_data->lock);
 
        return size;
 }
@@ -295,6 +277,7 @@ static int netdev_trig_notify(struct notifier_block *nb,
                netdev_notifier_info_to_dev((struct netdev_notifier_info *)dv);
        struct led_netdev_data *trigger_data =
                container_of(nb, struct led_netdev_data, notifier);
+       bool reset = true;
 
        if (evt != NETDEV_UP && evt != NETDEV_DOWN && evt != NETDEV_CHANGE
            && evt != NETDEV_REGISTER && evt != NETDEV_UNREGISTER
@@ -308,7 +291,7 @@ static int netdev_trig_notify(struct notifier_block *nb,
 
        cancel_delayed_work_sync(&trigger_data->work);
 
-       spin_lock_bh(&trigger_data->lock);
+       mutex_lock(&trigger_data->lock);
 
        trigger_data->linkup = 0;
        switch (evt) {
@@ -327,12 +310,14 @@ static int netdev_trig_notify(struct notifier_block *nb,
        case NETDEV_CHANGE:
                if (netif_carrier_ok(dev))
                        trigger_data->linkup = 1;
+               reset = !trigger_data->led_cdev->offloaded;
                break;
        }
 
-       set_baseline_state(trigger_data);
+       if (reset)
+               set_baseline_state(trigger_data);
 
-       spin_unlock_bh(&trigger_data->lock);
+       mutex_unlock(&trigger_data->lock);
 
        return NOTIFY_DONE;
 }
@@ -389,7 +374,7 @@ static int netdev_trig_activate(struct led_classdev 
*led_cdev)
        if (!trigger_data)
                return -ENOMEM;
 
-       spin_lock_init(&trigger_data->lock);
+       mutex_init(&trigger_data->lock);
 
        trigger_data->notifier.notifier_call = netdev_trig_notify;
        trigger_data->notifier.priority = 10;
@@ -423,12 +408,13 @@ static void netdev_trig_deactivate(struct led_classdev 
*led_cdev)
        kfree(trigger_data);
 }
 
-static struct led_trigger netdev_led_trigger = {
+struct led_trigger netdev_led_trigger = {
        .name = "netdev",
        .activate = netdev_trig_activate,
        .deactivate = netdev_trig_deactivate,
        .groups = netdev_trig_groups,
 };
+EXPORT_SYMBOL_GPL(netdev_led_trigger);
 
 static int __init netdev_trig_init(void)
 {
diff --git a/include/linux/ledtrig.h b/include/linux/ledtrig.h
new file mode 100644
index 000000000000..593b2bee6ca0
--- /dev/null
+++ b/include/linux/ledtrig.h
@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * LED trigger shared structures
+ */
+
+#ifndef __LINUX_LEDTRIG_H__
+#define __LINUX_LEDTRIG_H__
+
+#include <linux/atomic.h>
+#include <linux/leds.h>
+#include <linux/mutex.h>
+#include <linux/netdevice.h>
+
+#if IS_ENABLED(CONFIG_LEDS_TRIGGER_NETDEV)
+
+struct led_netdev_data {
+       struct mutex lock;
+
+       struct delayed_work work;
+       struct notifier_block notifier;
+
+       struct led_classdev *led_cdev;
+       struct net_device *net_dev;
+
+       char device_name[IFNAMSIZ];
+       atomic_t interval;
+       unsigned int last_activity;
+
+       unsigned link:1;
+       unsigned tx:1;
+       unsigned rx:1;
+
+       unsigned linkup:1;
+};
+
+extern struct led_trigger netdev_led_trigger;
+
+#endif /* IS_ENABLED(CONFIG_LEDS_TRIGGER_NETDEV) */
+
+#endif /* __LINUX_LEDTRIG_H__ */
-- 
2.26.2

Reply via email to