block/blk-cgroup-rwstat: use data_race() for online test

blkg_rwstat_recursive_sum() reads pos_blkg->online without the queue
lock that its doc comment requires, since blkcg_print_blkgs() stopped
holding it in 56cc24f59c14.  Concurrent blkg_create/destroy flips
->online, tripping KCSAN.  The race is harmless (RCU-protected, stale
online only causes minor stat noise).  Use data_race() to annotate
the intentional lockless read.

Also update the stale doc comment that still requires the queue lock.

Reviewed-by: Yu Kuai <yukuai@fygo.io>
Signed-off-by: Tao Cui <cuitao@kylinos.cn>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://patch.msgid.link/20260803133400.137906-1-cui.tao@linux.dev
Signed-off-by: Jens Axboe <axboe@kernel.dk>

0 files changed, 0 insertions, 0 deletions