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RDMA/core: introduce ib_dma_pci_p2p_dma_supported()

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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>
This commit is contained in:
Logan Gunthorpe 2022-07-08 10:51:02 -06:00 committed by Christoph Hellwig
parent 91fb2b6052
commit 495758bb1a
2 changed files with 12 additions and 1 deletions
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2
drivers/nvme/target/rdma.c
View file

@ -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;

11
include/rdma/ib_verbs.h
View file

@ -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