CVE-2021-47412

In the Linux kernel, the following vulnerability has been resolved: block:
don’t call rq_qos_ops->done_bio if the bio isn’t tracked rq_qos framework
is only applied on request based driver, so: 1) rq_qos_done_bio() needn’t
to be called for bio based driver 2) rq_qos_done_bio() needn’t to be called
for bio which isn’t tracked, such as bios ended from error handling code.
Especially in bio_endio(): 1) request queue is referred via
bio->bi_bdev->bd_disk->queue, which may be gone since request queue
refcount may not be held in above two cases 2) q->rq_qos may be freed in
blk_cleanup_queue() when calling into __rq_qos_done_bio() Fix the potential
kernel panic by not calling rq_qos_ops->done_bio if the bio isn’t tracked.
This way is safe because both ioc_rqos_done_bio() and
blkcg_iolatency_done_bio() are nop if the bio isn’t tracked.