--- zzzz-none-000/linux-4.4.271/block/genhd.c	2021-06-03 06:22:09.000000000 +0000
+++ hawkeye-5590-750/linux-4.4.271/block/genhd.c	2023-04-19 10:22:28.000000000 +0000
@@ -1120,6 +1120,22 @@
 		blk_put_queue(disk->queue);
 	kfree(disk);
 }
+
+static int disk_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	struct gendisk *disk = dev_to_disk(dev);
+	struct disk_part_iter piter;
+	struct hd_struct *part;
+	int cnt = 0;
+
+	disk_part_iter_init(&piter, disk, 0);
+	while((part = disk_part_iter_next(&piter)))
+		cnt++;
+	disk_part_iter_exit(&piter);
+	add_uevent_var(env, "NPARTS=%u", cnt);
+	return 0;
+}
+
 struct class block_class = {
 	.name		= "block",
 };
@@ -1139,6 +1155,7 @@
 	.groups		= disk_attr_groups,
 	.release	= disk_release,
 	.devnode	= block_devnode,
+	.uevent		= disk_uevent,
 };
 
 #ifdef CONFIG_PROC_FS