Commits
Jens Axboe committed ae994ea9724
cfq-iosched: fix other locations where blkcg_to_cfqgd() can return NULL
Commit 9470e4a693db only covered the initial bug report, there are
other spots in CFQ where we need to check that we actually have
a valid cfq_group_data structure.
Fixes: e48453c3 ("block, cgroup: implement policy-specific per-blkcg data")
Signed-off-by: Jens Axboe <axboe@fb.com>