ledtrig-netdev: switch rwlock to spinlock

Read/write lock was adding useless complexity, there wasn't any real
gain in case of this driver.
Also switch to _bh variants to avoid deadlocks.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Backport of r47986

SVN-Revision: 47989

diff --git a/target/linux/generic/files/drivers/leds/ledtrig-netdev.c b/target/linux/generic/files/drivers/leds/ledtrig-netdev.c
index 5e9b95f5ee3aed0f7e24d719d87aaeeb600a5db8..018392a9209bd4e6f2c204cb6669209ccc18a3e3 100644 (file)
--- a/target/linux/generic/files/drivers/leds/ledtrig-netdev.c
+++ b/target/linux/generic/files/drivers/leds/ledtrig-netdev.c
@@ -68,7 +68,7 @@
 #define MODE_RX   4
 
 struct led_netdev_data {
-       rwlock_t lock;
+       spinlock_t lock;
 
        struct timer_list timer;
        struct notifier_block notifier;
@@ -102,9 +102,9 @@ static ssize_t led_device_name_show(struct device *dev,
        struct led_classdev *led_cdev = dev_get_drvdata(dev);
        struct led_netdev_data *trigger_data = led_cdev->trigger_data;
 
-       read_lock(&trigger_data->lock);
+       spin_lock_bh(&trigger_data->lock);
        sprintf(buf, "%s\n", trigger_data->device_name);
-       read_unlock(&trigger_data->lock);
+       spin_unlock_bh(&trigger_data->lock);
 
        return strlen(buf) + 1;
 }
@@ -118,7 +118,7 @@ static ssize_t led_device_name_store(struct device *dev,
        if (size < 0 || size >= IFNAMSIZ)
                return -EINVAL;
 
-       write_lock(&trigger_data->lock);
+       spin_lock_bh(&trigger_data->lock);
 
        strcpy(trigger_data->device_name, buf);
        if (size > 0 && trigger_data->device_name[size-1] == '\n')
@@ -132,7 +132,7 @@ static ssize_t led_device_name_store(struct device *dev,
                set_baseline_state(trigger_data); /* updates LEDs, may start timers */
        }
 
-       write_unlock(&trigger_data->lock);
+       spin_unlock_bh(&trigger_data->lock);
        return size;
 }
 
@@ -144,7 +144,7 @@ static ssize_t led_mode_show(struct device *dev,
        struct led_classdev *led_cdev = dev_get_drvdata(dev);
        struct led_netdev_data *trigger_data = led_cdev->trigger_data;
 
-       read_lock(&trigger_data->lock);
+       spin_lock_bh(&trigger_data->lock);
 
        if (trigger_data->mode == 0) {
                strcpy(buf, "none\n");
@@ -158,7 +158,7 @@ static ssize_t led_mode_show(struct device *dev,
                strcat(buf, "\n");
        }
 
-       read_unlock(&trigger_data->lock);
+       spin_unlock_bh(&trigger_data->lock);
 
        return strlen(buf)+1;
 }
@@ -199,10 +199,10 @@ static ssize_t led_mode_store(struct device *dev,
        if (new_mode == -1)
                return -EINVAL;
 
-       write_lock(&trigger_data->lock);
+       spin_lock_bh(&trigger_data->lock);
        trigger_data->mode = new_mode;
        set_baseline_state(trigger_data);
-       write_unlock(&trigger_data->lock);
+       spin_unlock_bh(&trigger_data->lock);
 
        return size;
 }
@@ -215,9 +215,9 @@ static ssize_t led_interval_show(struct device *dev,
        struct led_classdev *led_cdev = dev_get_drvdata(dev);
        struct led_netdev_data *trigger_data = led_cdev->trigger_data;
 
-       read_lock(&trigger_data->lock);
+       spin_lock_bh(&trigger_data->lock);
        sprintf(buf, "%u\n", jiffies_to_msecs(trigger_data->interval));
-       read_unlock(&trigger_data->lock);
+       spin_unlock_bh(&trigger_data->lock);
 
        return strlen(buf) + 1;
 }
@@ -237,10 +237,10 @@ static ssize_t led_interval_store(struct device *dev,
 
        /* impose some basic bounds on the timer interval */
        if (count == size && value >= 5 && value <= 10000) {
-               write_lock(&trigger_data->lock);
+               spin_lock_bh(&trigger_data->lock);
                trigger_data->interval = msecs_to_jiffies(value);
                set_baseline_state(trigger_data); /* resets timer */
-               write_unlock(&trigger_data->lock);
+               spin_unlock_bh(&trigger_data->lock);
                ret = count;
        }
 
@@ -259,7 +259,7 @@ static int netdev_trig_notify(struct notifier_block *nb,
        if (evt != NETDEV_UP && evt != NETDEV_DOWN && evt != NETDEV_CHANGE && evt != NETDEV_REGISTER && evt != NETDEV_UNREGISTER)
                return NOTIFY_DONE;
 
-       write_lock(&trigger_data->lock);
+       spin_lock_bh(&trigger_data->lock);
 
        if (strcmp(dev->name, trigger_data->device_name))
                goto done;
@@ -285,7 +285,7 @@ static int netdev_trig_notify(struct notifier_block *nb,
        set_baseline_state(trigger_data);
 
 done:
-       write_unlock(&trigger_data->lock);
+       spin_unlock_bh(&trigger_data->lock);
        return NOTIFY_DONE;
 }
 
@@ -297,7 +297,7 @@ static void netdev_trig_timer(unsigned long arg)
        unsigned new_activity;
        struct rtnl_link_stats64 temp;
 
-       write_lock(&trigger_data->lock);
+       spin_lock(&trigger_data->lock);
 
        if (!trigger_data->link_up || !trigger_data->net_dev || (trigger_data->mode & (MODE_TX | MODE_RX)) == 0) {
                /* we don't need to do timer work, just reflect link state. */
@@ -336,7 +336,7 @@ static void netdev_trig_timer(unsigned long arg)
        mod_timer(&trigger_data->timer, jiffies + trigger_data->interval);
 
 no_restart:
-       write_unlock(&trigger_data->lock);
+       spin_unlock(&trigger_data->lock);
 }
 
 static void netdev_trig_activate(struct led_classdev *led_cdev)
@@ -348,7 +348,7 @@ static void netdev_trig_activate(struct led_classdev *led_cdev)
        if (!trigger_data)
                return;
 
-       rwlock_init(&trigger_data->lock);
+       spin_lock_init(&trigger_data->lock);
 
        trigger_data->notifier.notifier_call = netdev_trig_notify;
        trigger_data->notifier.priority = 10;
@@ -399,14 +399,14 @@ static void netdev_trig_deactivate(struct led_classdev *led_cdev)
                device_remove_file(led_cdev->dev, &dev_attr_mode);
                device_remove_file(led_cdev->dev, &dev_attr_interval);
 
-               write_lock(&trigger_data->lock);
+               spin_lock_bh(&trigger_data->lock);
 
                if (trigger_data->net_dev) {
                        dev_put(trigger_data->net_dev);
                        trigger_data->net_dev = NULL;
                }
 
-               write_unlock(&trigger_data->lock);
+               spin_unlock_bh(&trigger_data->lock);
 
                del_timer_sync(&trigger_data->timer);