On 11/17/21 1:53 PM, Logan Gunthorpe wrote: > Make use of the third free LSB in scatterlist's page_link on 64bit systems. > > The extra bit will be used by dma_[un]map_sg_p2pdma() to determine when a > given SGL segments dma_address points to a PCI bus address. > dma_unmap_sg_p2pdma() will need to perform different cleanup when a > segment is marked as a bus address. > > Create a CONFIG_NEED_SG_DMA_BUS_ADDR_FLAG bool which depends on > CONFIG_64BIT (so there is space in the page link for the new flag). > CONFIG_PCI_P2PDMA will then depend on this so this means PCI P2PDMA will > require CONFIG_64BIT. This should be acceptable as the majority of P2PDMA > use cases are restricted to newer root complexes and roughly require the > extra address space for memory BARs used in the transactions. > > Signed-off-by: Logan Gunthorpe <logang@xxxxxxxxxxxx> Looks good. Reviewed-by: Chaitanya Kulkarni <kch@xxxxxxxxxx>
