Re: [PATCH v6 06/11] rust: pci: drop driver data before remove returns

[sashiko-bot@kernel.org]

> From: Zhi Wang <zhiw@nvidia.com>
> 
> A Rust PCI driver's private data is currently dropped by
> driver::Registration::post_unbind_callback(). The driver core calls it
> from device_unbind_cleanup(), after the PCI bus remove callback,
> pci_device_remove(), has returned.
> 
> VF drivers will store a vfio::pci::Registration in their private data,
> which calls vfio_pci_core_register_device() when created and
> vfio_pci_core_unregister_device() when destroyed.
> 
> vfio_pci_core_unregister_device() expects to be called from
> pci_device_remove(), and hence can't be deferred beyond it. This also
> makes it incompatible with devres, i.e. a
> devm_vfio_pci_core_register_device() helper wouldn't work either, since
> devres_release_all() also runs from device_unbind_cleanup().
> 
> Hence, drop the private data in pci::Adapter::remove_callback(), so it
> is dropped before pci_device_remove() returns.
> 
> This is a special case for VFIO-PCI. In general, a driver's private
> data must not rely on being dropped from the bus remove callback; any
> point after the driver's remove callback and before devres_release_all()
> in device_unbind_cleanup() is sufficient.
> 
> Suggested-by: Danilo Krummrich <dakr@kernel.org>
> Signed-off-by: Zhi Wang <zhiw@nvidia.com>
> Signed-off-by: Simon Song <xinmengs@nvidia.com>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261111223337.508989-1-xinmengs@nvidia.com?part=6