The lli_lsm_sem locks taken by ll_prep_md_op_data() are sometimes
released by a different thread.  This confuses lockdep unless we
explain the situation.

So use down_read_non_owner() and up_read_non_owner().

Test-Parameters: trivial
Signed-off-by: Mr NeilBrown <neilb@suse.de>
Change-Id: Ie6543706c658fc427461ef03448f3fcf90abaab7
Reviewed-on: https://review.whamcloud.com/39234


Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Shaun Tancheff <shaun.tancheff@hpe.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>