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>>> >>> +/** >>> + * dma_buf_get_pci_tph - Retrieve PCIe TLP Processing Hint (TPH) metadata >>> + * @dmabuf: DMA buffer to query >>> + * @extended: false for 8-bit ST, true for 16-bit Extended ST >>> + * @steering_tag: returns the raw steering tag for the requested namespace >>> + * @ph: returns the TPH processing hint >>> + * >>> + * Wrapper for the optional &dma_buf_ops.get_pci_tph callback. >>> + * >>> + * Must be called with &dma_buf.resv held. Returns -EOPNOTSUPP if the >>> + * exporter does not implement the callback or has no metadata for the >>> + * requested namespace. >> >> Please add something like this: >> >> * The returned information is only valid till the next invalidate_mappings() callback from the exporter and should be re-queried when a new mapping is created after invalidation. >> > > Thanks, Will do in v11! > >> Apart from that it looks good to me, but I still think we need some kind of example that this works for other DMA-buf users as well. >> >> Just demonstrating that this also works with some simple FPGA or similar PCIe endpoint should be sufficient. >> >> Regards, >> Christian. >> > > On v10, I have validated a second importer: another vendor's NIC > (driver not upstream yet, so locally patched to > call dma_buf_get_pci_tph). A PCIe analyzer confirms the TLP steering > tag matches the exporter's for both mlx5/ConnectX-8 > and this second NIC — two unrelated importer drivers exercising the > API end-to-end. That sounds like it would be sufficient, yes. Thanks, Christian. > > Thanks, > Zhiping