@@ -14,3 +14,55 @@ MODULE_DESCRIPTION("Block device LED trigger");
 MODULE_AUTHOR("Ian Pilcher <arequipeno@gmail.com>");
 MODULE_LICENSE("GPL v2");
 MODULE_IMPORT_NS(LEDTRIG_BLKDEV);
+
+/* Default blink time & polling interval (milliseconds) */
+#define LEDTRIG_BLKDEV_BLINK_MSEC	75
+#define LEDTRIG_BLKDEV_INTERVAL		100
+
+/* Minimum VALUE for interval or blink_time */
+#define LEDTRIG_BLKDEV_MIN_TIME		25
+
+enum ledtrig_blkdev_mode {
+	LEDTRIG_BLKDEV_MODE_RO	= 0,	/* blink for reads */
+	LEDTRIG_BLKDEV_MODE_WO	= 1,	/* blink for writes */
+	LEDTRIG_BLKDEV_MODE_RW	= 2	/* blink for reads and writes */
+};
+
+/* Trigger-specific info about a block device */
+struct ledtrig_blkdev_disk {
+	struct gendisk		*gd;
+	struct kobject		*dir;		/* blkdev_leds dir */
+	struct hlist_head	leds;
+	unsigned long		read_ios;
+	unsigned long		write_ios;
+	unsigned int		generation;
+	bool			read_act;
+	bool			write_act;
+};
+
+/* For many-to-many relationships between "disks" (block devices) and LEDs */
+struct ledtrig_blkdev_link {
+	struct hlist_node		disk_leds_node;
+	struct hlist_node		led_disks_node;
+	struct ledtrig_blkdev_disk	*disk;
+	struct ledtrig_blkdev_led	*led;
+};
+
+/* Every LED associated with the blkdev trigger gets one of these */
+struct ledtrig_blkdev_led {
+	struct kobject			*dir;		/* block_devices dir */
+	struct led_classdev		*led_dev;
+	unsigned int			blink_msec;
+	struct hlist_head		disks;		/* linked block devs */
+	struct hlist_node		leds_node;
+	enum ledtrig_blkdev_mode	mode;
+};
+
+/* All LEDs associated with the trigger */
+static HLIST_HEAD(ledtrig_blkdev_leds);
+
+/* Total number of device-to-LED associations */
+static unsigned int ledtrig_blkdev_count;
+
+/* How often to check for drive activity - in jiffies */
+static unsigned int ledtrig_blkdev_interval;