mainline inclusion
from mainline-5.11-rc1
commit b0d97557
category: bugfix
bugzilla: 108592
CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b0d97557ebfc9d5ba5f2939339a9fdd267abafeb

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

The inflight of partition 0 doesn't include inflight IOs to all
sub-partitions, since currently mq calculates inflight of specific
partition by simply camparing the value of the partition pointer.

Thus the following case is possible:

$ cat /sys/block/vda/inflight
       0        0
$ cat /sys/block/vda/vda1/inflight
       0      128

While single queue device (on a previous version, e.g. v3.10) has no
this issue:

$cat /sys/block/sda/sda3/inflight
       0       33
$cat /sys/block/sda/inflight
       0       33

Partition 0 should be specially handled since it represents the whole
disk. This issue is introduced since commit bf0ddaba ("blk-mq: fix
sysfs inflight counter").

Besides, this patch can also fix the inflight statistics of part 0 in
/proc/diskstats. Before this patch, the inflight statistics of part 0
doesn't include that of sub partitions. (I have marked the 'inflight'
field with asterisk.)

$cat /proc/diskstats
 259       0 nvme0n1 45974469 0 367814768 6445794 1 0 1 0 *0* 111062 6445794 0 0 0 0 0 0
 259       2 nvme0n1p1 45974058 0 367797952 6445727 0 0 0 0 *33* 111001 6445727 0 0 0 0 0 0

This is introduced since commit f299b7c7 ("blk-mq: provide internal
in-flight variant").

Fixes: bf0ddaba ("blk-mq: fix sysfs inflight counter")
Fixes: f299b7c7 ("blk-mq: provide internal in-flight variant")
Signed-off-by: NJeffle Xu <jefflexu@linux.alibaba.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
[axboe: adapt for 5.11 partition change]
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Conflicts:
	block/blk-mq.c
Signed-off-by: Nyangerkun <yangerkun@huawei.com>
Reviewed-by: NYufen Yu <yuyufen@huawei.com>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>