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

[Shivaji Kant]

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 at google.com>
Signed-off-by: Shivaji Kant <shivajikant at 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,
 };
 
 /*
-- 
2.53.0.1185.g05d4b7b318-goog