Re: [PATCH v8 10/11] dm: call dm_zone_endio after the target endio callback for zoned devices

From: Pankaj Raghav
Date: Fri Jul 29 2022 - 04:48:19 EST


>> if (endio) {
>> int r = endio(ti, bio, &error);
>> switch (r) {
>> @@ -1155,6 +1151,10 @@ static void clone_endio(struct bio *bio)
>> }
>> }
>>
>> + if (static_branch_unlikely(&zoned_enabled) &&
>> + unlikely(bdev_is_zoned(bio->bi_bdev)))
>> + dm_zone_endio(io, bio);
>> +
>> if (static_branch_unlikely(&swap_bios_enabled) &&
>> unlikely(swap_bios_limit(ti, bio)))
>> up(&md->swap_bios_semaphore);
>
> This patch seems completely unrelated to the series topic. Is that a bug
> fix ? How do you trigger it ? Our tests do not show any issues here...
> If this triggers only with non power of 2 zone size devices, then this
> should be squashed in patch 8. And patch 9 could also be squashed with
> patch 8 too.
>
The targets that support zoned devices such as dm-zoned, dm-linear, and
dm-crypt do not have an endio function, and even if they do (such as
dm-flakey), they don't modify the bio->bi_iter.bi_sector of the cloned
bio that is used to update the orig_bio's bi_sector in dm_zone_endio
function.

This path is triggered only for the new target dm-po2zone and not for
npo2 zone size devices in general. I will mention this is a prep patch
for the new target because I wouldn't call it a bug per se.