Hello,

with transition to blk-mq, the elevator= kernel argument was removed. I
understand the reasons for its removal but still I think this may come as a
surprise to some users since that argument has been there for ages and
although distributions generally transition to setting appropriate elevator
by udev rules, there are still people that use that argument with older
kernels and there are quite a few advices on the Internet to use it. So
shouldn't we at least warn loudly if someone uses elevator= argument on
kernels that don't support it and redirect people to sysfs? Something like
the attached patch? What do people think?

								Honza

-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR