[PATCH v3 12/14] PCI/P2PDMA: dma_map() requests that traverse the host bridge

From: Logan Gunthorpe <logang@deltatee.com>
To: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
	linux-nvme@lists.infradead.org, linux-rdma@vger.kernel.org
Cc: Bjorn Helgaas <bhelgaas@google.com>,
	Christoph Hellwig <hch@lst.de>,
	Christian Koenig <Christian.Koenig@amd.com>,
	Jason Gunthorpe <jgg@mellanox.com>,
	Sagi Grimberg <sagi@grimberg.me>, Keith Busch <kbusch@kernel.org>,
	Jens Axboe <axboe@fb.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Eric Pilmore <epilmore@gigaio.com>,
	Stephen Bates <sbates@raithlin.com>,
	Logan Gunthorpe <logang@deltatee.com>
Subject: [PATCH v3 12/14] PCI/P2PDMA: dma_map() requests that traverse the host bridge
Date: Mon, 12 Aug 2019 11:30:46 -0600	[thread overview]
Message-ID: <20190812173048.9186-13-logang@deltatee.com> (raw)
In-Reply-To: <20190812173048.9186-1-logang@deltatee.com>

Any requests that traverse the host bridge will need to be mapped into the
IOMMU, so call dma_map_sg() inside pci_p2pdma_map_sg() when appropriate.

Similarly, call dma_unmap_sg() inside pci_p2pdma_unmap_sg().

Link: https://lore.kernel.org/r/20190730163545.4915-13-logang@deltatee.com
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
 drivers/pci/p2pdma.c | 40 +++++++++++++++++++++++++++++++++++++++-
 1 file changed, 39 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index db8224ff6e80..bca1ffc7075e 100644
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -807,6 +807,16 @@ void pci_p2pmem_publish(struct pci_dev *pdev, bool publish)
 }
 EXPORT_SYMBOL_GPL(pci_p2pmem_publish);
 
+static enum pci_p2pdma_map_type pci_p2pdma_map_type(struct pci_dev *provider,
+						    struct pci_dev *client)
+{
+	if (!provider->p2pdma)
+		return PCI_P2PDMA_MAP_NOT_SUPPORTED;
+
+	return xa_to_value(xa_load(&provider->p2pdma->map_types,
+				   map_types_idx(client)));
+}
+
 static int __pci_p2pdma_map_sg(struct pci_p2pdma_pagemap *p2p_pgmap,
 		struct device *dev, struct scatterlist *sg, int nents)
 {
@@ -852,8 +862,22 @@ int pci_p2pdma_map_sg_attrs(struct device *dev, struct scatterlist *sg,
 {
 	struct pci_p2pdma_pagemap *p2p_pgmap =
 		to_p2p_pgmap(sg_page(sg)->pgmap);
+	struct pci_dev *client;
 
-	return __pci_p2pdma_map_sg(p2p_pgmap, dev, sg, nents);
+	if (WARN_ON_ONCE(!dev_is_pci(dev)))
+		return 0;
+
+	client = to_pci_dev(dev);
+
+	switch (pci_p2pdma_map_type(p2p_pgmap->provider, client)) {
+	case PCI_P2PDMA_MAP_THRU_HOST_BRIDGE:
+		return dma_map_sg_attrs(dev, sg, nents, dir, attrs);
+	case PCI_P2PDMA_MAP_BUS_ADDR:
+		return __pci_p2pdma_map_sg(p2p_pgmap, dev, sg, nents);
+	default:
+		WARN_ON_ONCE(1);
+		return 0;
+	}
 }
 EXPORT_SYMBOL_GPL(pci_p2pdma_map_sg_attrs);
 
@@ -869,6 +893,20 @@ EXPORT_SYMBOL_GPL(pci_p2pdma_map_sg_attrs);
 void pci_p2pdma_unmap_sg_attrs(struct device *dev, struct scatterlist *sg,
 		int nents, enum dma_data_direction dir, unsigned long attrs)
 {
+	struct pci_p2pdma_pagemap *p2p_pgmap =
+		to_p2p_pgmap(sg_page(sg)->pgmap);
+	enum pci_p2pdma_map_type map_type;
+	struct pci_dev *client;
+
+	if (WARN_ON_ONCE(!dev_is_pci(dev)))
+		return;
+
+	client = to_pci_dev(dev);
+
+	map_type = pci_p2pdma_map_type(p2p_pgmap->provider, client);
+
+	if (map_type == PCI_P2PDMA_MAP_THRU_HOST_BRIDGE)
+		dma_unmap_sg_attrs(dev, sg, nents, dir, attrs);
 }
 EXPORT_SYMBOL_GPL(pci_p2pdma_unmap_sg_attrs);
 
-- 
2.20.1

