media: staging: greybus: light: fix memory leak in v4l2 register

We are allocating memory for the v4l2 flash configuration structure and
leak it in the normal path. Just use the stack for this as we do not
use it outside of this function.

Also use IS_ERR() instead of IS_ERR_OR_NULL() to check return value from
v4l2_flash_init() for it never returns NULL.

Fixes: 2870b52bae4c ("greybus: lights: add lights implementation")

Reported-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Rui Miguel Silva <rmfrfs@gmail.com>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/staging/greybus/light.c

@@ -534,25 +534,20 @@ static int gb_lights_light_v4l2_register(struct gb_light *light)
 {
 	struct gb_connection *connection = get_conn_from_light(light);
 	struct device *dev = &connection->bundle->dev;
-	struct v4l2_flash_config *sd_cfg;
+	struct v4l2_flash_config sd_cfg = { {0} };
 	struct led_classdev_flash *fled;
 	struct led_classdev *iled = NULL;
 	struct gb_channel *channel_torch, *channel_ind, *channel_flash;
-	int ret = 0;
-
-	sd_cfg = kcalloc(1, sizeof(*sd_cfg), GFP_KERNEL);
-	if (!sd_cfg)
-		return -ENOMEM;
 
 	channel_torch = get_channel_from_mode(light, GB_CHANNEL_MODE_TORCH);
 	if (channel_torch)
 		__gb_lights_channel_v4l2_config(&channel_torch->intensity_uA,
-						&sd_cfg->torch_intensity);
+						&sd_cfg.torch_intensity);
 
 	channel_ind = get_channel_from_mode(light, GB_CHANNEL_MODE_INDICATOR);
 	if (channel_ind) {
 		__gb_lights_channel_v4l2_config(&channel_ind->intensity_uA,
-						&sd_cfg->indicator_intensity);
+						&sd_cfg.indicator_intensity);
 		iled = &channel_ind->fled.led_cdev;
 	}
 
@@ -561,27 +556,21 @@ static int gb_lights_light_v4l2_register(struct gb_light *light)
 
 	fled = &channel_flash->fled;
 
-	snprintf(sd_cfg->dev_name, sizeof(sd_cfg->dev_name), "%s", light->name);
+	snprintf(sd_cfg.dev_name, sizeof(sd_cfg.dev_name), "%s", light->name);
 
 	/* Set the possible values to faults, in our case all faults */
-	sd_cfg->flash_faults = LED_FAULT_OVER_VOLTAGE | LED_FAULT_TIMEOUT |
+	sd_cfg.flash_faults = LED_FAULT_OVER_VOLTAGE | LED_FAULT_TIMEOUT |
 		LED_FAULT_OVER_TEMPERATURE | LED_FAULT_SHORT_CIRCUIT |
 		LED_FAULT_OVER_CURRENT | LED_FAULT_INDICATOR |
 		LED_FAULT_UNDER_VOLTAGE | LED_FAULT_INPUT_VOLTAGE |
 		LED_FAULT_LED_OVER_TEMPERATURE;
 
 	light->v4l2_flash = v4l2_flash_init(dev, NULL, fled, iled,
-					    &v4l2_flash_ops, sd_cfg);
-	if (IS_ERR_OR_NULL(light->v4l2_flash)) {
-		ret = PTR_ERR(light->v4l2_flash);
-		goto out_free;
-	}
+					    &v4l2_flash_ops, &sd_cfg);
+	if (IS_ERR(light->v4l2_flash))
+		return PTR_ERR(light->v4l2_flash);
 
-	return ret;
-
-out_free:
-	kfree(sd_cfg);
-	return ret;
+	return 0;
 }
 
 static void gb_lights_light_v4l2_unregister(struct gb_light *light)