From: Logan Gunthorpe <logang@deltatee.com>
To: linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org,
linux-block@vger.kernel.org, linux-pci@vger.kernel.org,
linux-mm@kvack.org, iommu@lists.linux-foundation.org
Cc: "Stephen Bates" <sbates@raithlin.com>,
"Christoph Hellwig" <hch@lst.de>,
"Dan Williams" <dan.j.williams@intel.com>,
"Jason Gunthorpe" <jgg@ziepe.ca>,
"Christian König" <christian.koenig@amd.com>,
"John Hubbard" <jhubbard@nvidia.com>,
"Don Dutile" <ddutile@redhat.com>,
"Matthew Wilcox" <willy@infradead.org>,
"Daniel Vetter" <daniel.vetter@ffwll.ch>,
"Jakowski Andrzej" <andrzej.jakowski@intel.com>,
"Minturn Dave B" <dave.b.minturn@intel.com>,
"Jason Ekstrand" <jason@jlekstrand.net>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
"Xiong Jianxin" <jianxin.xiong@intel.com>,
"Bjorn Helgaas" <helgaas@kernel.org>,
"Ira Weiny" <ira.weiny@intel.com>,
"Robin Murphy" <robin.murphy@arm.com>,
"Martin Oliveira" <martin.oliveira@eideticom.com>,
"Chaitanya Kulkarni" <ckulkarnilinux@gmail.com>,
"Ralph Campbell" <rcampbell@nvidia.com>,
"Logan Gunthorpe" <logang@deltatee.com>,
"Bjorn Helgaas" <bhelgaas@google.com>
Subject: [PATCH v6 04/21] PCI/P2PDMA: Introduce helpers for dma_map_sg implementations
Date: Thu, 7 Apr 2022 09:47:00 -0600 [thread overview]
Message-ID: <20220407154717.7695-5-logang@deltatee.com> (raw)
In-Reply-To: <20220407154717.7695-1-logang@deltatee.com>
Add pci_p2pdma_map_segment() as a helper for simple dma_map_sg()
implementations. It takes an scatterlist segment that must point to a
pci_p2pdma struct page and will map it if the mapping requires a bus
address.
The return value indicates whether the mapping required a bus address
or whether the caller still needs to map the segment normally. If the
segment should not be mapped, -EREMOTEIO is returned.
This helper uses a state structure to track the changes to the
pgmap across calls and avoid needing to lookup into the xarray for
every page.
Also add pci_p2pdma_map_bus_segment() which is useful for IOMMU
dma_map_sg() implementations where the sg segment containing the page
differs from the sg segment containing the DMA address.
Prototypes for these helpers are added to dma-map-ops.h as they are only
useful to dma map implementations and don't need to pollute the public
pci-p2pdma header.
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
---
drivers/pci/p2pdma.c | 59 +++++++++++++++++++++++++++++++++++++
include/linux/dma-map-ops.h | 21 +++++++++++++
2 files changed, 80 insertions(+)
diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index 8573bf9d651a..9032c2ed2cdf 100644
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -946,6 +946,65 @@ void pci_p2pdma_unmap_sg_attrs(struct device *dev, struct scatterlist *sg,
}
EXPORT_SYMBOL_GPL(pci_p2pdma_unmap_sg_attrs);
+/**
+ * pci_p2pdma_map_segment - map an sg segment determining the mapping type
+ * @state: State structure that should be declared outside of the for_each_sg()
+ * loop and initialized to zero.
+ * @dev: DMA device that's doing the mapping operation
+ * @sg: scatterlist segment to map
+ *
+ * This is a helper to be used by non-IOMMU dma_map_sg() implementations where
+ * the sg segment is the same for the page_link and the dma_address.
+ *
+ * Attempt to map a single segment in an SGL with the PCI bus address.
+ * The segment must point to a PCI P2PDMA page and thus must be
+ * wrapped in a is_pci_p2pdma_page(sg_page(sg)) check.
+ *
+ * Returns the type of mapping used and maps the page if the type is
+ * PCI_P2PDMA_MAP_BUS_ADDR.
+ */
+enum pci_p2pdma_map_type
+pci_p2pdma_map_segment(struct pci_p2pdma_map_state *state, struct device *dev,
+ struct scatterlist *sg)
+{
+ if (state->pgmap != sg_page(sg)->pgmap) {
+ state->pgmap = sg_page(sg)->pgmap;
+ state->map = pci_p2pdma_map_type(state->pgmap, dev);
+ state->bus_off = to_p2p_pgmap(state->pgmap)->bus_offset;
+ }
+
+ if (state->map == PCI_P2PDMA_MAP_BUS_ADDR) {
+ sg->dma_address = sg_phys(sg) + state->bus_off;
+ sg_dma_len(sg) = sg->length;
+ sg_dma_mark_bus_address(sg);
+ }
+
+ return state->map;
+}
+
+/**
+ * pci_p2pdma_map_bus_segment - map an sg segment pre determined to
+ * be mapped with PCI_P2PDMA_MAP_BUS_ADDR
+ * @pg_sg: scatterlist segment with the page to map
+ * @dma_sg: scatterlist segment to assign a DMA address to
+ *
+ * This is a helper for iommu dma_map_sg() implementations when the
+ * segment for the DMA address differs from the segment containing the
+ * source page.
+ *
+ * pci_p2pdma_map_type() must have already been called on the pg_sg and
+ * returned PCI_P2PDMA_MAP_BUS_ADDR.
+ */
+void pci_p2pdma_map_bus_segment(struct scatterlist *pg_sg,
+ struct scatterlist *dma_sg)
+{
+ struct pci_p2pdma_pagemap *pgmap = to_p2p_pgmap(sg_page(pg_sg)->pgmap);
+
+ dma_sg->dma_address = sg_phys(pg_sg) + pgmap->bus_offset;
+ sg_dma_len(dma_sg) = pg_sg->length;
+ sg_dma_mark_bus_address(dma_sg);
+}
+
/**
* pci_p2pdma_enable_store - parse a configfs/sysfs attribute store
* to enable p2pdma
diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h
index d693a0e33bac..752f91e5eb5d 100644
--- a/include/linux/dma-map-ops.h
+++ b/include/linux/dma-map-ops.h
@@ -413,15 +413,36 @@ enum pci_p2pdma_map_type {
PCI_P2PDMA_MAP_THRU_HOST_BRIDGE,
};
+struct pci_p2pdma_map_state {
+ struct dev_pagemap *pgmap;
+ int map;
+ u64 bus_off;
+};
+
#ifdef CONFIG_PCI_P2PDMA
enum pci_p2pdma_map_type pci_p2pdma_map_type(struct dev_pagemap *pgmap,
struct device *dev);
+enum pci_p2pdma_map_type
+pci_p2pdma_map_segment(struct pci_p2pdma_map_state *state, struct device *dev,
+ struct scatterlist *sg);
+void pci_p2pdma_map_bus_segment(struct scatterlist *pg_sg,
+ struct scatterlist *dma_sg);
#else /* CONFIG_PCI_P2PDMA */
static inline enum pci_p2pdma_map_type
pci_p2pdma_map_type(struct dev_pagemap *pgmap, struct device *dev)
{
return PCI_P2PDMA_MAP_NOT_SUPPORTED;
}
+static inline enum pci_p2pdma_map_type
+pci_p2pdma_map_segment(struct pci_p2pdma_map_state *state, struct device *dev,
+ struct scatterlist *sg)
+{
+ return PCI_P2PDMA_MAP_NOT_SUPPORTED;
+}
+static inline void pci_p2pdma_map_bus_segment(struct scatterlist *pg_sg,
+ struct scatterlist *dma_sg)
+{
+}
#endif /* CONFIG_PCI_P2PDMA */
#endif /* _LINUX_DMA_MAP_OPS_H */
--
2.30.2
next prev parent reply other threads:[~2022-04-07 17:23 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-07 15:46 [PATCH v6 00/21] Userspace P2PDMA with O_DIRECT NVMe devices Logan Gunthorpe
2022-04-07 15:46 ` [PATCH v6 01/21] lib/scatterlist: add flag for indicating P2PDMA segments in an SGL Logan Gunthorpe
2022-04-07 15:46 ` [PATCH v6 02/21] PCI/P2PDMA: Attempt to set map_type if it has not been set Logan Gunthorpe
2022-04-07 15:46 ` [PATCH v6 03/21] PCI/P2PDMA: Expose pci_p2pdma_map_type() Logan Gunthorpe
2022-04-07 15:47 ` Logan Gunthorpe [this message]
2022-04-07 15:47 ` [PATCH v6 05/21] dma-mapping: allow EREMOTEIO return code for P2PDMA transfers Logan Gunthorpe
2022-04-07 15:47 ` [PATCH v6 06/21] dma-direct: support PCI P2PDMA pages in dma-direct map_sg Logan Gunthorpe
2022-04-07 15:47 ` [PATCH v6 07/21] dma-mapping: add flags to dma_map_ops to indicate PCI P2PDMA support Logan Gunthorpe
2022-04-07 15:47 ` [PATCH v6 08/21] iommu/dma: support PCI P2PDMA pages in dma-iommu map_sg Logan Gunthorpe
2022-04-07 15:47 ` [PATCH v6 09/21] nvme-pci: check DMA ops when indicating support for PCI P2PDMA Logan Gunthorpe
2022-04-07 15:47 ` [PATCH v6 10/21] nvme-pci: convert to using dma_map_sgtable() Logan Gunthorpe
2022-04-07 15:47 ` [PATCH v6 11/21] RDMA/core: introduce ib_dma_pci_p2p_dma_supported() Logan Gunthorpe
2022-04-07 15:47 ` [PATCH v6 12/21] RDMA/rw: drop pci_p2pdma_[un]map_sg() Logan Gunthorpe
2022-04-07 15:47 ` [PATCH v6 13/21] PCI/P2PDMA: Remove pci_p2pdma_[un]map_sg() Logan Gunthorpe
2022-04-07 15:47 ` [PATCH v6 14/21] mm: introduce FOLL_PCI_P2PDMA to gate getting PCI P2PDMA pages Logan Gunthorpe
2022-04-07 15:47 ` [PATCH v6 15/21] iov_iter: introduce iov_iter_get_pages_[alloc_]flags() Logan Gunthorpe
2022-04-07 15:47 ` [PATCH v6 16/21] block: add check when merging zone device pages Logan Gunthorpe
2022-04-07 15:47 ` [PATCH v6 17/21] lib/scatterlist: " Logan Gunthorpe
2022-04-07 15:47 ` [PATCH v6 18/21] block: set FOLL_PCI_P2PDMA in __bio_iov_iter_get_pages() Logan Gunthorpe
2022-04-07 15:47 ` [PATCH v6 19/21] block: set FOLL_PCI_P2PDMA in bio_map_user_iov() Logan Gunthorpe
2022-04-07 15:47 ` [PATCH v6 20/21] PCI/P2PDMA: Introduce pci_mmap_p2pmem() Logan Gunthorpe
2022-05-27 12:55 ` Jason Gunthorpe
2022-05-27 15:35 ` Logan Gunthorpe
2022-05-27 19:03 ` Jason Gunthorpe
2022-05-27 22:41 ` Logan Gunthorpe
2022-06-02 0:00 ` Jason Gunthorpe
2022-06-02 16:16 ` Logan Gunthorpe
2022-06-02 16:30 ` Jason Gunthorpe
2022-06-02 16:45 ` Logan Gunthorpe
2022-06-02 17:18 ` Jason Gunthorpe
2022-06-02 16:49 ` Logan Gunthorpe
2022-06-02 17:28 ` Jason Gunthorpe
2022-06-02 17:49 ` Logan Gunthorpe
2022-04-07 15:47 ` [PATCH v6 21/21] nvme-pci: allow mmaping the CMB in userspace Logan Gunthorpe
2022-05-16 22:31 ` [PATCH v6 00/21] Userspace P2PDMA with O_DIRECT NVMe devices Chaitanya Kulkarni
2022-05-16 22:35 ` Logan Gunthorpe
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