[PATCH 1/3 v3] thinkpad_acpi: return -NODEV while operating uninitialized LEDs

[Adam Lee <adam.lee@canonical.com>]

Not all 0-15 LEDs are available for all models, sometimes it's even not
safe. This patch return -NODEV while operating uninitialized LEDs.

Signed-off-by: Adam Lee <adam.lee@canonical.com>
---
 drivers/platform/x86/thinkpad_acpi.c |   10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index 54d31c0..455384b 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -369,7 +369,7 @@ struct tpacpi_led_classdev {
 	struct led_classdev led_classdev;
 	struct work_struct work;
 	enum led_status_t new_state;
-	unsigned int led;
+	int led;
 };
 
 /* brightness level capabilities */
@@ -5344,6 +5344,8 @@ static int __init led_init(struct ibm_init_struct *iibm)
 					  ARRAY_SIZE(led_useful_qtable));
 
 	for (i = 0; i < TPACPI_LED_NUMLEDS; i++) {
+		tpacpi_leds[i].led = -1;
+
 		if (!tpacpi_is_led_restricted(i) &&
 		    test_bit(i, &useful_leds)) {
 			rc = tpacpi_init_led(i);
@@ -5401,9 +5403,13 @@ static int led_write(char *buf)
 		return -ENODEV;
 
 	while ((cmd = next_cmd(&buf))) {
-		if (sscanf(cmd, "%d", &led) != 1 || led < 0 || led > 15)
+		if (sscanf(cmd, "%d", &led) != 1)
 			return -EINVAL;
 
+		if (led < 0 || led > (TPACPI_LED_NUMLEDS - 1) ||
+				tpacpi_leds[led].led < 0)
+			return -ENODEV;
+
 		if (strstr(cmd, "off")) {
 			s = TPACPI_LED_OFF;
 		} else if (strstr(cmd, "on")) {
-- 
1.7.10.4