RE: [PATCH v2 3/3] iommufd/device: Change iommufd_hw_pagetable_has_group to device centric

Tian, Kevin
2023-02-02T06:33:08Z

> From: Nicolin Chen <nicolinc@nvidia.com>
> Sent: Wednesday, February 1, 2023 3:20 PM
>
> So, assuming we drop this series and move the first two patches
> back to the nesting series or the replace series, one of them
> would end up doing something ugly:
>
> if (cur_hwpt != hwpt)
> mutex_lock(&cur_hwpt->device_lock);
> mutex_lock(&hwpt->device_lock);
> ...
> mutex_unlock(&hwpt->device_lock);
> if (cur_hwpt != hwpt)
> mutex_unlock(&cur_hwpt->device_lock);
>
> So, perhaps we should discuss about which way we want to choose.

from your discussion with Jason I think this locking open has
been settled down.

>
> Btw, Baolu's version has a similar patch as mine changing the
> iommu_attach/detach_device(), yet also touches _group(). Could
> we bisect that series into _device() first and _group() later?
> Given that we only need a device-centric API at this moment...
>

I'll let Baolu to decide after he re-catches up the comments in
that thread. But overall I think we now agreed that removing the
device list/lock can be kept out of your replace/nesting series
and let it cleaned up after Baolu's work completes, correct? 😊