Description of problem:
blockdev fails to report information about disk devices:

[root@localhost ~]# blockdev --report /dev/sda
RO    RA   SSZ   BSZ   StartSec            Size   Device
blockdev: /dev/sda: failed to read partition start from sysfs: No such file or directory
[root@localhost ~]#


But it is possible to display information about partitions on that disk:

[root@localhost ~]# blockdev --report /dev/sda1 
RO    RA   SSZ   BSZ   StartSec            Size   Device
rw   256   512  1024       2048       524288000   /dev/sda1
[root@localhost ~]# blockdev --report /dev/sda2
RO    RA   SSZ   BSZ   StartSec            Size   Device
rw   256   512  4096    1026048      8064598016   /dev/sda2
[root@localhost ~]#


Older version of util-linux (2.26-0.2.fc22) works correctly:

[root@localhost ~]# blockdev --report /dev/sda
RO    RA   SSZ   BSZ   StartSec            Size   Device
rw   256   512  4096          0      8589934592   /dev/sda
[root@localhost ~]#

Version-Release number of selected component (if applicable):
util-linux-2.26-1.fc22.x86_64
kernel 4.0.0-0.rc3.git0.1.fc22.x86_64 and 3.18.9-200.fc21.x86_64

How reproducible:
always

Steps to Reproduce:
1. blockdev --report /dev/sda

Actual results:
blockdev: /dev/sda: failed to read partition start from sysfs: No such file or directory

Expected results:
disk information is printed

Additional information:
This regression has been introduced between util-linux-2.26-0.2.fc22 (works fine) and util-linux-2.26-0.3.fc22 (fails)