Re: [PATCH v5 3/6] PCI: endpoint: Add API to delegate EPC DMA channels to the host

[sashiko-bot@kernel.org]

> Some endpoint functions expose an EPC-integrated DMA controller to the
> host. The endpoint function should not need to know the backend-specific
> mechanism used to reserve a channel locally and hand its programming
> interface to the host.
> 
> Add pci_epc_delegate_dma_chan() and pci_epc_reclaim_dma_chan().
> Add matching EPC operations. The public API returns an opaque handle,
> while the EPC backend keeps any private channel state. This lets generic
> endpoint functions delegate channels without depending on a specific
> DMAengine provider.
> 
> Let reclaim callers tell the backend whether hardware exposed to host
> programming needs to be quiesced before local ownership is restored.
> The quiesce may cover a provider-defined sharing group, so callers must
> hold every delegated member and stop peer programming before reclaim.
> Bind failure paths that only unwind local reservations can skip quiesce.
> 
> Reclaim is best-effort because it runs from teardown paths that cannot be
> aborted. The backend always consumes the delegation and reports any
> quiesce failure itself. The opaque handle is always freed.
> 
> Signed-off-by: Koichiro Den <den@valinux.co.jp>

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

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Sashiko AI review · https://sashiko.dev/#/patchset/20260717050635.2145014-1-den@valinux.co.jp?part=3