Commit 495758bb authored Jul 08, 2022 by Logan Gunthorpe Committed by Christoph Hellwig Jul 26, 2022

RDMA/core: introduce ib_dma_pci_p2p_dma_supported()



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 <logang@deltatee.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>

parent 91fb2b60

drivers/nvme/target/rdma.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -415,7 +415,7 @@ 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;

include/rdma/ib_verbs.h

+11 −0

Original line number	Diff line number	Diff line
		@@ -4013,6 +4013,17 @@ 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