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Message-Id: <20210513223203.5542-21-logang@deltatee.com>
Date: Thu, 13 May 2021 16:32:01 -0600
From: Logan Gunthorpe <logang@...tatee.com>
To: linux-kernel@...r.kernel.org, linux-nvme@...ts.infradead.org,
linux-block@...r.kernel.org, linux-pci@...r.kernel.org,
linux-mm@...ck.org, iommu@...ts.linux-foundation.org
Cc: Stephen Bates <sbates@...thlin.com>,
Christoph Hellwig <hch@....de>,
Dan Williams <dan.j.williams@...el.com>,
Jason Gunthorpe <jgg@...pe.ca>,
Christian König <christian.koenig@....com>,
John Hubbard <jhubbard@...dia.com>,
Don Dutile <ddutile@...hat.com>,
Matthew Wilcox <willy@...radead.org>,
Daniel Vetter <daniel.vetter@...ll.ch>,
Jakowski Andrzej <andrzej.jakowski@...el.com>,
Minturn Dave B <dave.b.minturn@...el.com>,
Jason Ekstrand <jason@...kstrand.net>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Xiong Jianxin <jianxin.xiong@...el.com>,
Bjorn Helgaas <helgaas@...nel.org>,
Ira Weiny <ira.weiny@...el.com>,
Robin Murphy <robin.murphy@....com>,
Logan Gunthorpe <logang@...tatee.com>
Subject: [PATCH v2 20/22] 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@...tatee.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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