block: genhd: Add disk/partition specific uevent callbacks for partition info

	For disk devices, a new uevent parameter 'NPARTS' specifies the number
of partitions detected by the kernel. Partition devices get 'PARTN' which
specifies the partitions index in the table.

Signed-off-by: San Mehat <san@google.com>

2 files changed, 27 insertions, 0 deletions

diff --git a/block/genhd.c b/block/genhd.c
index 95822ae..50b61c3 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1105,6 +1105,22 @@ static void disk_release(struct device *dev)
 	free_part_info(&disk->part0);
 	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",
 };
@@ -1123,6 +1139,7 @@ static struct device_type disk_type = {
 	.groups		= disk_attr_groups,
 	.release	= disk_release,
 	.devnode	= block_devnode,
+	.uevent		= disk_uevent,
 };
 
 #ifdef CONFIG_PROC_FS
diff --git a/fs/partitions/check.c b/fs/partitions/check.c
index d545e97..d9b8329 100644
--- a/fs/partitions/check.c
+++ b/fs/partitions/check.c
@@ -366,10 +366,20 @@ static void part_release(struct device *dev)
 	kfree(p);
 }
 
+static int part_uevent(struct device *dev, struct kobj_uvent_env *env)
+{
+	struct gendisk *disk = dev_to_disk(dev);
+	struct hd_struct *part = dev_to_part(dev);
+
+	add_uevent_var(env, "PARTN=%u", part->partno);
+	return 0;
+}
+
 struct device_type part_type = {
 	.name		= "partition",
 	.groups		= part_attr_groups,
 	.release	= part_release,
+	.uevent		= part_uevent,
 };
 
 static void delete_partition_rcu_cb(struct rcu_head *head)