Introduce the helper function ib_dma_pci_p2p_dma_supported() to check
if a given ib_device can be used in P2PDMA transfers. This ensures
the ib_device is not using virt_dma and also that the underlying
dma_device supports P2PDMA.
Use the new helper in nvme-rdma to replace the existing check for
ib_uses_virt_dma(). Adding the dma_pci_p2pdma_supported() check allows
switching away from pci_p2pdma_[un]map_sg().
Signed-off-by: Logan Gunthorpe <log...@deltatee.com>
---
drivers/nvme/target/rdma.c | 2 +-
include/rdma/ib_verbs.h | 11 +++++++++++
2 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c
index 6c1f3ab7649c..86f0bf4dc1ca 100644
--- a/drivers/nvme/target/rdma.c
+++ b/drivers/nvme/target/rdma.c
@@ -414,7 +414,7 @@ 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_dma_pci_p2p_dma_supported(ndev->device))
r->req.p2p_client = &ndev->device->dev;
r->send_sge.length = sizeof(*r->req.cqe);
r->send_sge.lkey = ndev->pd->local_dma_lkey;
diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index 7e2f3699b898..724e80a656f7 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -3943,6 +3943,17 @@ static inline bool ib_uses_virt_dma(struct ib_device
*dev)
return IS_ENABLED(CONFIG_INFINIBAND_VIRT_DMA) && !dev->dma_device;
}
+/*
+ * Check if a IB device's underlying DMA mapping supports P2PDMA transfers.
+ */
+static inline bool ib_dma_pci_p2p_dma_supported(struct ib_device *dev)
+{
+ if (ib_uses_virt_dma(dev))
+ return false;
+
+ return dma_pci_p2pdma_supported(dev->dma_device);
+}
+
/**
* ib_dma_mapping_error - check a DMA addr for error
* @dev: The device for which the dma_addr was created
--
2.20.1
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