mainline inclusion
from mainline-v6.0-rc1
commit 14a6e2eb
category: bugfix
bugzilla: 188088, https://gitee.com/openeuler/kernel/issues/I66GIL
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=14a6e2eb7df5c7897c15b109cba29ab0c4a791b6

----------------------------------------------------------------------

In our test of iocost, we encountered some list add/del corruptions of
inner_walk list in ioc_timer_fn.

The reason can be described as follows:

cpu 0					cpu 1
ioc_qos_write				ioc_qos_write

ioc = q_to_ioc(queue);
if (!ioc) {
        ioc = kzalloc();
					ioc = q_to_ioc(queue);
					if (!ioc) {
						ioc = kzalloc();
						...
						rq_qos_add(q, rqos);
					}
        ...
        rq_qos_add(q, rqos);
        ...
}

When the io.cost.qos file is written by two cpus concurrently, rq_qos may
be added to one disk twice. In that case, there will be two iocs enabled
and running on one disk. They own different iocgs on their active list. In
the ioc_timer_fn function, because of the iocgs from two iocs have the
same root iocg, the root iocg's walk_list may be overwritten by each other
and this leads to list add/del corruptions in building or destroying the
inner_walk list.

And so far, the blk-rq-qos framework works in case that one instance for
one type rq_qos per queue by default. This patch make this explicit and
also fix the crash above.
Signed-off-by: NJinke Han <hanjinke.666@bytedance.com>
Reviewed-by: NMuchun Song <songmuchun@bytedance.com>
Acked-by: NTejun Heo <tj@kernel.org>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220720093616.70584-1-hanjinke.666@bytedance.comSigned-off-by: NJens Axboe <axboe@kernel.dk>

Conflicts:
	block/blk-rq-qos.h
	block/blk-wbt.c
Signed-off-by: NLi Nan <linan122@huawei.com>
Reviewed-by: NHou Tao <houtao1@huawei.com>
(cherry picked from commit 8ce9b7c4)