When WWID does not end in digit, no `p` is added to the partition name of a multipath device in RHEL7

Issue

• When WWID does not end in digit, no p is added to the partition name of a multipath device. However, when the WWID ends in digit, kpartx adds p to the partition name.
• kpartx fails silently when adding partition to multipath device in RHEL7

For example :

# multipath -ll
0QEMU_QEMU_HARDDISK_drive-scsi0-0-0-0 dm-3 QEMU    ,QEMU HARDDISK    <--- WWID ending in digit
size=20G features='0' hwhandler='0' wp=rw
`-+- policy='service-time 0' prio=1 status=active
  `- 2:0:0:0 sda 8:0 active ready running


root@dhcp210-194 ~]# fdisk /dev/mapper/0QEMU_QEMU_HARDDISK_drive-scsi0-0-0-0 
Welcome to fdisk (util-linux 2.23.2).

                Device Boot      Start         End      Blocks   Id  System

Command (m for help): n
Partition type:
   p   primary (0 primary, 0 extended, 4 free)
   e   extended
Select (default p): p
Partition number (1-4, default 1): 1
First sector (2048-41943039, default 2048): 
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-41943039, default 41943039): 
Using default value 41943039
Partition 1 of type Linux and of size 20 GiB is set

Command (m for help): w
The partition table has been altered!


[root@dhcp210-194 ~]# kpartx -a -v /dev/mapper/0QEMU_QEMU_HARDDISK_drive-scsi0-0-0-0 
add map 0QEMU_QEMU_HARDDISK_drive-scsi0-0-0-0p1 (253:4): 0 41940992 linear /dev/mapper/0QEMU_QEMU_HARDDISK_drive-scsi0-0-0-0 2048

[root@dhcp210-194 ~]# ls -l /dev/mapper/0QEMU_QEMU_HARDDISK_drive-scsi0-0-0-0*
lrwxrwxrwx. 1 root root 7 Aug 30 04:45 /dev/mapper/0QEMU_QEMU_HARDDISK_drive-scsi0-0-0-0 -> ../dm-3
lrwxrwxrwx. 1 root root 7 Aug 30 04:45 /dev/mapper/0QEMU_QEMU_HARDDISK_drive-scsi0-0-0-0p1 -> ../dm-4  <-- `p` is added to represent partition

=======================================================================

    multipath {
        wwid            0QEMU_QEMU_HARDDISK_drive-scsi0-0-0-0
        alias           mpatha
    }


[root@dhcp210-194 ~]# multipath -ll
mpatha (0QEMU_QEMU_HARDDISK_drive-scsi0-0-0-0) dm-3 QEMU    ,QEMU HARDDISK   <-- WWID does not end with digit
size=20G features='0' hwhandler='0' wp=rw
`-+- policy='service-time 0' prio=1 status=active
  `- 2:0:0:0 sda 8:0 active ready running
[root@dhcp210-194 ~]# fdisk /dev/mapper/mpatha 

Select (default p): p
Partition number (1-4, default 1): 1
First sector (2048-41943039, default 2048): 
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-41943039, default 41943039): 
Using default value 41943039
Partition 1 of type Linux and of size 20 GiB is set

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.

[root@dhcp210-194 ~]# kpartx -a -v /dev/mapper/mpatha 
add map mpatha1 (253:4): 0 41940992 linear /dev/mapper/mpatha 2048

[root@dhcp210-194 ~]# ls -l /dev/mapper/mpatha*
lrwxrwxrwx. 1 root root 7 Aug 30 04:50 /dev/mapper/mpatha -> ../dm-3
lrwxrwxrwx. 1 root root 7 Aug 30 04:50 /dev/mapper/mpatha1 -> ../dm-4   <---------  no `p` is added