Re: [RFC PATCH v2] nvme: enable PCI P2PDMA support for RDMA transport

[Pranjal Shrivastava <praan@google.com>]

On Thu, Apr 02, 2026 at 07:30:01AM +0000, Shivaji Kant wrote:
> Enable BLK_FEAT_PCI_P2PDMA on the NVMe when the underlying
> RDMA controller supports it.
> 
> This patch depends on the PCI P2PDMA support added in this
> patch [1].
> 
> Suggested-by: Pranjal Shrivastava <praan@google.com>
> Signed-off-by: Shivaji Kant <shivajikant@google.com>
> ---
> [1] https://lore.kernel.org/all/20260323234416.46944-3-kch@nvidia.com/
> ---
>  drivers/nvme/host/rdma.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
> index 35c0822edb2d..09eefd7c3ff4 100644
> --- a/drivers/nvme/host/rdma.c
> +++ b/drivers/nvme/host/rdma.c
> @@ -2189,6 +2189,13 @@ static void nvme_rdma_reset_ctrl_work(struct work_struct *work)
>  	nvme_rdma_reconnect_or_remove(ctrl, ret);
>  }
>  
> +static bool nvme_rdma_supports_pci_p2pdma(struct nvme_ctrl *ctrl)
> +{
> +	struct nvme_rdma_ctrl *r_ctrl = to_rdma_ctrl(ctrl);
> +
> +	return ib_dma_pci_p2p_dma_supported(r_ctrl->device->dev);
> +}
> +
>  static const struct nvme_ctrl_ops nvme_rdma_ctrl_ops = {
>  	.name			= "rdma",
>  	.module			= THIS_MODULE,
> @@ -2203,6 +2210,7 @@ static const struct nvme_ctrl_ops nvme_rdma_ctrl_ops = {
>  	.get_address		= nvmf_get_address,
>  	.stop_ctrl		= nvme_rdma_stop_ctrl,
>  	.get_virt_boundary	= nvme_get_virt_boundary,
> +	.supports_pci_p2pdma	= nvme_rdma_supports_pci_p2pdma,
>  };
>  

+Chaitanya.

Hi Chaitanya, would you like to pick this up with your v2 for the
multipath p2p enablement series [1] ?

For the changes (with Chaitanya's mpath patch):
Reviewed-by: Pranjal Shrivastava <praan@google.com>

Thanks,
Praan

[1] https://lore.kernel.org/all/20260323234416.46944-3-kch@nvidia.com/