CVE-2021-47412

In the Linux kernel, the following vulnerability has been resolved:

block: don't call rqqosops->done_bio if the bio isn't tracked

rq_qos framework is only applied on request based driver, so:

1) rqqosdone_bio() needn't to be called for bio based driver

2) rqqosdone_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->bibdev->bddisk->queue, which may be gone since request queue refcount may not be held in above two cases

2) q->rqqos may be freed in blkcleanupqueue() when calling into _rqqosdone_bio()

Fix the potential kernel panic by not calling rqqosops->donebio if the bio isn't tracked. This way is safe because both iocrqosdonebio() and blkcgiolatencydone_bio() are nop if the bio isn't tracked.