The kbd led code has multiple entry points each of which modifies the
kbd_state by reading it, modifying a copy, writing the copy and on
error setting the modified copy writing back the original state.
This is racy, so add a mutex protection the read-modify-write cycle
on each of the entry points.
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
Changes in v8:
-New patch in v8 of this patch-set
---
drivers/platform/x86/dell-laptop.c | 112 +++++++++++++++++++++++++------------
1 file changed, 76 insertions(+), 36 deletions(-)
diff --git a/drivers/platform/x86/dell-laptop.c b/drivers/platform/x86/dell-laptop.c
index a2913a5..70951f3 100644
--- a/drivers/platform/x86/dell-laptop.c
+++ b/drivers/platform/x86/dell-laptop.c
@@ -1133,6 +1133,7 @@ static u8 kbd_previous_level;
static u8 kbd_previous_mode_bit;
static bool kbd_led_present;
+static DEFINE_MUTEX(kbd_led_mutex);
/*
* NOTE: there are three ways to set the keyboard backlight level.
@@ -1562,9 +1563,11 @@ static ssize_t kbd_led_timeout_store(struct device *dev,
}
}
+ mutex_lock(&kbd_led_mutex);
+
ret = kbd_get_state(&state);
if (ret)
- return ret;
+ goto out;
new_state = state;
new_state.timeout_value = value;
@@ -1572,9 +1575,12 @@ static ssize_t kbd_led_timeout_store(struct device *dev,
ret = kbd_set_state_safe(&new_state, &state);
if (ret)
- return ret;
+ goto out;
- return count;
+ ret = count;
+out:
+ mutex_unlock(&kbd_led_mutex);
+ return ret;
}
static ssize_t kbd_led_timeout_show(struct device *dev,
@@ -1634,9 +1640,11 @@ static ssize_t kbd_led_triggers_store(struct device *dev,
if (trigger[0] != '+' && trigger[0] != '-')
return -EINVAL;
+ mutex_lock(&kbd_led_mutex);
+
ret = kbd_get_state(&state);
if (ret)
- return ret;
+ goto out;
if (kbd_triggers_supported)
triggers_enabled = kbd_is_trigger_mode_bit(state.mode_bit);
@@ -1650,18 +1658,24 @@ static ssize_t kbd_led_triggers_store(struct device *dev,
if (strcmp(trigger+1, kbd_led_triggers[i]) != 0)
continue;
if (trigger[0] == '+' &&
- triggers_enabled && (state.triggers & BIT(i)))
- return count;
+ triggers_enabled && (state.triggers & BIT(i))) {
+ ret = count;
+ goto out;
+ }
if (trigger[0] == '-' &&
- (!triggers_enabled || !(state.triggers & BIT(i))))
- return count;
+ (!triggers_enabled || !(state.triggers & BIT(i)))) {
+ ret = count;
+ goto out;
+ }
trigger_bit = i;
break;
}
}
- if (trigger_bit == -1)
- return -EINVAL;
+ if (trigger_bit == -1) {
+ ret = -EINVAL;
+ goto out;
+ }
new_state = state;
if (trigger[0] == '+')
@@ -1677,22 +1691,29 @@ static ssize_t kbd_led_triggers_store(struct device *dev,
new_state.triggers &= ~BIT(2);
}
if ((kbd_info.triggers & new_state.triggers) !=
- new_state.triggers)
- return -EINVAL;
+ new_state.triggers) {
+ ret = -EINVAL;
+ goto out;
+ }
if (new_state.triggers && !triggers_enabled) {
new_state.mode_bit = KBD_MODE_BIT_TRIGGER;
kbd_set_level(&new_state, kbd_previous_level);
} else if (new_state.triggers == 0) {
kbd_set_level(&new_state, 0);
}
- if (!(kbd_info.modes & BIT(new_state.mode_bit)))
- return -EINVAL;
+ if (!(kbd_info.modes & BIT(new_state.mode_bit))) {
+ ret = -EINVAL;
+ goto out;
+ }
ret = kbd_set_state_safe(&new_state, &state);
if (ret)
- return ret;
+ goto out;
if (new_state.mode_bit != KBD_MODE_BIT_OFF)
kbd_previous_mode_bit = new_state.mode_bit;
- return count;
+ ret = count;
+out:
+ mutex_unlock(&kbd_led_mutex);
+ return ret;
}
static ssize_t kbd_led_triggers_show(struct device *dev,
@@ -1749,12 +1770,16 @@ static ssize_t kbd_led_als_enabled_store(struct device *dev,
if (ret)
return ret;
+ mutex_lock(&kbd_led_mutex);
+
ret = kbd_get_state(&state);
if (ret)
- return ret;
+ goto out;
- if (enable == kbd_is_als_mode_bit(state.mode_bit))
- return count;
+ if (enable == kbd_is_als_mode_bit(state.mode_bit)) {
+ ret = count;
+ goto out;
+ }
new_state = state;
@@ -1774,15 +1799,20 @@ static ssize_t kbd_led_als_enabled_store(struct device *dev,
new_state.mode_bit = KBD_MODE_BIT_ON;
}
}
- if (!(kbd_info.modes & BIT(new_state.mode_bit)))
- return -EINVAL;
+ if (!(kbd_info.modes & BIT(new_state.mode_bit))) {
+ ret = -EINVAL;
+ goto out;
+ }
ret = kbd_set_state_safe(&new_state, &state);
if (ret)
- return ret;
+ goto out;
kbd_previous_mode_bit = new_state.mode_bit;
- return count;
+ ret = count;
+out:
+ mutex_unlock(&kbd_led_mutex);
+ return ret;
}
static ssize_t kbd_led_als_enabled_show(struct device *dev,
@@ -1817,18 +1847,23 @@ static ssize_t kbd_led_als_setting_store(struct device *dev,
if (ret)
return ret;
+ mutex_lock(&kbd_led_mutex);
+
ret = kbd_get_state(&state);
if (ret)
- return ret;
+ goto out;
new_state = state;
new_state.als_setting = setting;
ret = kbd_set_state_safe(&new_state, &state);
if (ret)
- return ret;
+ goto out;
- return count;
+ ret = count;
+out:
+ mutex_unlock(&kbd_led_mutex);
+ return ret;
}
static ssize_t kbd_led_als_setting_show(struct device *dev,
@@ -1913,27 +1948,32 @@ static int kbd_led_level_set(struct led_classdev *led_cdev,
u16 num;
int ret;
+ mutex_lock(&kbd_led_mutex);
+
if (kbd_get_max_level()) {
ret = kbd_get_state(&state);
if (ret)
- return ret;
+ goto out;
new_state = state;
ret = kbd_set_level(&new_state, value);
if (ret)
- return ret;
- return kbd_set_state_safe(&new_state, &state);
- }
-
- if (kbd_get_valid_token_counts()) {
+ goto out;
+ ret = kbd_set_state_safe(&new_state, &state);
+ } else if (kbd_get_valid_token_counts()) {
for (num = kbd_token_bits; num != 0 && value > 0; --value)
num &= num - 1; /* clear the first bit set */
if (num == 0)
- return 0;
- return kbd_set_token_bit(ffs(num) - 1);
+ ret = 0;
+ else
+ ret = kbd_set_token_bit(ffs(num) - 1);
+ } else {
+ pr_warn("Keyboard brightness level control not supported\n");
+ ret = -ENXIO;
}
- pr_warn("Keyboard brightness level control not supported\n");
- return -ENXIO;
+out:
+ mutex_unlock(&kbd_led_mutex);
+ return ret;
}
static struct led_classdev kbd_led = {
--
2.9.3
