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author | Richard Purdie <rpurdie@rpsys.net> | 2007-11-10 14:29:04 +0100 |
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committer | Richard Purdie <rpurdie@rpsys.net> | 2007-12-07 10:06:53 +0100 |
commit | dc47206e552c0850ad11f7e9a1fca0a3c92f5d65 (patch) | |
tree | 01188f5ca89d295009a618e1be6c5cea2926a522 /drivers/leds/led-triggers.c | |
parent | Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/... (diff) | |
download | linux-dc47206e552c0850ad11f7e9a1fca0a3c92f5d65.tar.xz linux-dc47206e552c0850ad11f7e9a1fca0a3c92f5d65.zip |
leds: Fix led trigger locking bugs
Convert part of the led trigger core from rw spinlocks to rw
semaphores. We're calling functions which can sleep from invalid
contexts otherwise. Fixes bug #9264.
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Diffstat (limited to 'drivers/leds/led-triggers.c')
-rw-r--r-- | drivers/leds/led-triggers.c | 49 |
1 files changed, 25 insertions, 24 deletions
diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c index 575368c2b100..0bdb786210b1 100644 --- a/drivers/leds/led-triggers.c +++ b/drivers/leds/led-triggers.c @@ -19,13 +19,14 @@ #include <linux/device.h> #include <linux/sysdev.h> #include <linux/timer.h> +#include <linux/rwsem.h> #include <linux/leds.h> #include "leds.h" /* * Nests outside led_cdev->trigger_lock */ -static DEFINE_RWLOCK(triggers_list_lock); +static DECLARE_RWSEM(triggers_list_lock); static LIST_HEAD(trigger_list); ssize_t led_trigger_store(struct device *dev, struct device_attribute *attr, @@ -44,24 +45,24 @@ ssize_t led_trigger_store(struct device *dev, struct device_attribute *attr, trigger_name[len - 1] = '\0'; if (!strcmp(trigger_name, "none")) { - write_lock(&led_cdev->trigger_lock); + down_write(&led_cdev->trigger_lock); led_trigger_set(led_cdev, NULL); - write_unlock(&led_cdev->trigger_lock); + up_write(&led_cdev->trigger_lock); return count; } - read_lock(&triggers_list_lock); + down_read(&triggers_list_lock); list_for_each_entry(trig, &trigger_list, next_trig) { if (!strcmp(trigger_name, trig->name)) { - write_lock(&led_cdev->trigger_lock); + down_write(&led_cdev->trigger_lock); led_trigger_set(led_cdev, trig); - write_unlock(&led_cdev->trigger_lock); + up_write(&led_cdev->trigger_lock); - read_unlock(&triggers_list_lock); + up_read(&triggers_list_lock); return count; } } - read_unlock(&triggers_list_lock); + up_read(&triggers_list_lock); return -EINVAL; } @@ -74,8 +75,8 @@ ssize_t led_trigger_show(struct device *dev, struct device_attribute *attr, struct led_trigger *trig; int len = 0; - read_lock(&triggers_list_lock); - read_lock(&led_cdev->trigger_lock); + down_read(&triggers_list_lock); + down_read(&led_cdev->trigger_lock); if (!led_cdev->trigger) len += sprintf(buf+len, "[none] "); @@ -89,8 +90,8 @@ ssize_t led_trigger_show(struct device *dev, struct device_attribute *attr, else len += sprintf(buf+len, "%s ", trig->name); } - read_unlock(&led_cdev->trigger_lock); - read_unlock(&triggers_list_lock); + up_read(&led_cdev->trigger_lock); + up_read(&triggers_list_lock); len += sprintf(len+buf, "\n"); return len; @@ -145,14 +146,14 @@ void led_trigger_set_default(struct led_classdev *led_cdev) if (!led_cdev->default_trigger) return; - read_lock(&triggers_list_lock); - write_lock(&led_cdev->trigger_lock); + down_read(&triggers_list_lock); + down_write(&led_cdev->trigger_lock); list_for_each_entry(trig, &trigger_list, next_trig) { if (!strcmp(led_cdev->default_trigger, trig->name)) led_trigger_set(led_cdev, trig); } - write_unlock(&led_cdev->trigger_lock); - read_unlock(&triggers_list_lock); + up_write(&led_cdev->trigger_lock); + up_read(&triggers_list_lock); } int led_trigger_register(struct led_trigger *trigger) @@ -163,18 +164,18 @@ int led_trigger_register(struct led_trigger *trigger) INIT_LIST_HEAD(&trigger->led_cdevs); /* Add to the list of led triggers */ - write_lock(&triggers_list_lock); + down_write(&triggers_list_lock); list_add_tail(&trigger->next_trig, &trigger_list); - write_unlock(&triggers_list_lock); + up_write(&triggers_list_lock); /* Register with any LEDs that have this as a default trigger */ read_lock(&leds_list_lock); list_for_each_entry(led_cdev, &leds_list, node) { - write_lock(&led_cdev->trigger_lock); + down_write(&led_cdev->trigger_lock); if (!led_cdev->trigger && led_cdev->default_trigger && !strcmp(led_cdev->default_trigger, trigger->name)) led_trigger_set(led_cdev, trigger); - write_unlock(&led_cdev->trigger_lock); + up_write(&led_cdev->trigger_lock); } read_unlock(&leds_list_lock); @@ -206,17 +207,17 @@ void led_trigger_unregister(struct led_trigger *trigger) struct led_classdev *led_cdev; /* Remove from the list of led triggers */ - write_lock(&triggers_list_lock); + down_write(&triggers_list_lock); list_del(&trigger->next_trig); - write_unlock(&triggers_list_lock); + up_write(&triggers_list_lock); /* Remove anyone actively using this trigger */ read_lock(&leds_list_lock); list_for_each_entry(led_cdev, &leds_list, node) { - write_lock(&led_cdev->trigger_lock); + down_write(&led_cdev->trigger_lock); if (led_cdev->trigger == trigger) led_trigger_set(led_cdev, NULL); - write_unlock(&led_cdev->trigger_lock); + up_write(&led_cdev->trigger_lock); } read_unlock(&leds_list_lock); } |