[libmultipath] scalability fix for devt2devname()
[libmultipath] scalability fix for devt2devname()

Move from the sysfs /block/*/dev nodes walking in search of maj:min
to a single file walking (/proc/partitions)

Based on idea and initial implementation from Hannes Reinecke, Suse.

unakatsuo/multipath-tools,gebi/multipath-tools,unakatsuo/multipath-tools,grzn/multipath-tools-explained,unakatsuo/multipath-tools,vijaychauhan/multipath-tools,grzn/multipath-tools-explained,vijaychauhan/multipath-tools