Re: [PATCH 14/16] nvme-rdma: Ensure dma support when using p2pdma

Jason Gunthorpe
2021-04-27T19:48:02Z

On Thu, Apr 08, 2021 at 11:01:21AM -0600, Logan Gunthorpe wrote:
> Ensure the dma operations support p2pdma before using the RDMA
> device for P2PDMA. This allows switching the RDMA driver from
> pci_p2pdma_map_sg() to dma_map_sg_p2pdma().
>
> Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
> drivers/nvme/target/rdma.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c
> index 6c1f3ab7649c..3ec7e77e5416 100644
> +++ b/drivers/nvme/target/rdma.c
> @@ -414,7 +414,8 @@ static int nvmet_rdma_alloc_rsp(struct nvmet_rdma_device *ndev,
> if (ib_dma_mapping_error(ndev->device, r->send_sge.addr))
> goto out_free_rsp;
>
> - if (!ib_uses_virt_dma(ndev->device))
> + if (!ib_uses_virt_dma(ndev->device) &&
> + dma_pci_p2pdma_supported(&ndev->device->dev))

ib_uses_virt_dma() should not be called by nvme and this is using the
wrong device pointer to query for DMA related properties.

I suspect this wants a ib_dma_pci_p2p_dma_supported() wrapper like
everything else.

Jason