addpart — tell the kernel about the existence of a partition
addpart device partition
addpart tells the Linux kernel about the existence of the specified partition. The command is a simple wrapper around the "add partition" ioctl.
This command doesn't manipulate partitions on a block device.
The disk device.
The partition number.
The beginning of the partition (in 512-byte sectors).
The length of the partition (in 512-byte sectors).