Re: [PATCH v2 4/6] iommu/virtio: stop queueing and draining once the device is removed

[sashiko-bot@kernel.org]

> viommu_remove() resets the device and deletes the virtqueues while
> userspace may still hold domains that it maps or attaches, and nothing
> stopped a request from being queued - or a drain from walking the queue -
> on a virtqueue that was being torn down.
> 
> Set ->removed under request_lock before the teardown - the lock a
> queueing path holds while it checks liveness and adds the request, and
> the one the drain holds for its whole run - check it in the queueing
> helper, and let the drain return early when it is set.
> 
> A drain that returns early leaves the requests still on the queue
> behind, and the device cannot complete them either.  Detach them
> from the request virtqueue - which unmaps their DMA mappings - and
> free them after the device is reset, when it can no longer be using
> them, and before the queues are deleted, so that the objects do not
> leak.
> 
> Fixes: edcd69ab9a32 ("iommu: Add virtio-iommu driver")
> Signed-off-by: Anlai Lu <agicy@qq.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/tencent_D757B544955DDC509B5DC7161F425620BA08@qq.com?part=4