[RFC PATCH v2 03/10] block: Add block device LED trigger fields to gendisk structure

[Ian Pilcher <arequipeno@xxxxxxxxx>]

Add header (blk-ledtrig.h) for LED trigger-related declarations

Add (inline) function to ensure trigger pointer is initialized
(to NULL) and call it from __device_add_disk()

Signed-off-by: Ian Pilcher <arequipeno@xxxxxxxxx>
---
 block/blk-ledtrig.h   | 25 +++++++++++++++++++++++++
 block/genhd.c         |  2 ++
 include/linux/genhd.h |  4 ++++
 3 files changed, 31 insertions(+)
 create mode 100644 block/blk-ledtrig.h

diff --git a/block/blk-ledtrig.h b/block/blk-ledtrig.h
new file mode 100644
index 000000000000..95a79d2fe447
--- /dev/null
+++ b/block/blk-ledtrig.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+/*
+ *	Block device LED triggers
+ *
+ *	Copyright 2021 Ian Pilcher <arequipeno@xxxxxxxxx>
+ */
+
+#ifndef _BLOCK_BLK_LEDTRIG_H
+#define _BLOCK_BLK_LEDTRIG_H
+
+#ifdef CONFIG_BLK_LED_TRIGGERS
+
+static inline void blk_ledtrig_disk_init(struct gendisk *const disk)
+{
+	RCU_INIT_POINTER(disk->led, NULL);
+}
+
+#else	// CONFIG_BLK_LED_TRIGGERS
+
+static inline void blk_ledtrig_disk_init(const struct gendisk *disk) {}
+
+#endif	// CONFIG_BLK_LED_TRIGGERS
+
+#endif	// _BLOCK_BLK_LEDTRIG_H
diff --git a/block/genhd.c b/block/genhd.c
index 298ee78c1bda..b168172e664b 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -26,6 +26,7 @@
 #include <linux/badblocks.h>
 
 #include "blk.h"
+#include "blk-ledtrig.h"
 
 static struct kobject *block_depr;
 
@@ -539,6 +540,7 @@ static void __device_add_disk(struct device *parent, struct gendisk *disk,
 
 	disk_add_events(disk);
 	blk_integrity_add(disk);
+	blk_ledtrig_disk_init(disk);
 }
 
 void device_add_disk(struct device *parent, struct gendisk *disk,
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 13b34177cc85..efcb1ca62f17 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -168,6 +168,10 @@ struct gendisk {
 #endif	/* CONFIG_BLK_DEV_INTEGRITY */
 #if IS_ENABLED(CONFIG_CDROM)
 	struct cdrom_device_info *cdi;
+#endif
+#ifdef CONFIG_BLK_LED_TRIGGERS
+	struct blk_ledtrig_led __rcu *led;
+	struct list_head led_dev_list_node;
 #endif
 	int node_id;
 	struct badblocks *bb;
-- 
2.31.1