Re: [PATCH v10 01/24] PCI/P2PDMA: Refactor the p2pdma mapping helpers

Baolu Lu
2025-04-29T02:12:58Z

On 4/28/25 17:22, Leon Romanovsky wrote:
> From: Christoph Hellwig<hch@lst.de>
>
> The current scheme with a single helper to determine the P2P status
> and map a scatterlist segment force users to always use the map_sg
> helper to DMA map, which we're trying to get away from because they
> are very cache inefficient.
>
> Refactor the code so that there is a single helper that checks the P2P
> state for a page, including the result that it is not a P2P page to
> simplify the callers, and a second one to perform the address translation
> for a bus mapped P2P transfer that does not depend on the scatterlist
> structure.
>
> Signed-off-by: Christoph Hellwig<hch@lst.de>
> Reviewed-by: Logan Gunthorpe<logang@deltatee.com>
> Acked-by: Bjorn Helgaas<bhelgaas@google.com>
> Tested-by: Jens Axboe<axboe@kernel.dk>
> Reviewed-by: Luis Chamberlain<mcgrof@kernel.org>
> Signed-off-by: Leon Romanovsky<leonro@nvidia.com>

Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>