Comment # 25 on bug 904517 from Robert Milasan

Re-wrote a bit the rule, we should only set/write the scheduler on ADD event,
CHANGE events happen a lot of times, especially when creating/removing
partitions or changing in some way the disk/partitions.

cat /usr/lib/udev/rules.d/60-ssd-scheduler.rules

ACTION!="add", GOTO="ssd_scheduler_end"
SUBSYSTEM!="block", GOTO="ssd_scheduler_end"

IMPORT{cmdline}="elevator"
ENV{elevator}=="*?", GOTO="ssd_scheduler_end"

KERNEL=="sd*[!0-9]", ATTR{queue/rotational}=="0",
ATTR{queue/scheduler}="deadline"

LABEL="ssd_scheduler_end"