[PATCH 09/16] dma-direct: Support PCI P2PDMA pages in dma-direct map_sg
From: Logan Gunthorpe <logang@deltatee.com>
Date: 2021-04-08 17:02:21
Also in:
linux-block, linux-iommu, linux-mm, linux-pci, lkml
Subsystem:
dma mapping helpers, the rest · Maintainers:
Marek Szyprowski, Linus Torvalds
Add PCI P2PDMA support for dma_direct_map_sg() so that it can map PCI P2PDMA pages directly without a hack in the callers. This allows for heterogeneous SGLs that contain both P2PDMA and regular pages. SGL segments that contain PCI bus addresses are marked with sg_mark_pci_p2pdma() and are ignored when unmapped. Signed-off-by: Logan Gunthorpe <logang@deltatee.com> --- kernel/dma/direct.c | 25 ++++++++++++++++++++++--- 1 file changed, 22 insertions(+), 3 deletions(-)
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 002268262c9a..108dfb4ecbd5 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c@@ -13,6 +13,7 @@ #include <linux/vmalloc.h> #include <linux/set_memory.h> #include <linux/slab.h> +#include <linux/pci-p2pdma.h> #include "direct.h" /*
@@ -387,19 +388,37 @@ void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sgl, struct scatterlist *sg; int i; - for_each_sg(sgl, sg, nents, i) + for_each_sg(sgl, sg, nents, i) { + if (sg_is_pci_p2pdma(sg)) { + sg_unmark_pci_p2pdma(sg); + continue; + } + dma_direct_unmap_page(dev, sg->dma_address, sg_dma_len(sg), dir, attrs); + } } #endif int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents, enum dma_data_direction dir, unsigned long attrs) { - int i; + struct pci_p2pdma_map_state p2pdma_state = {}; struct scatterlist *sg; + int i, ret = 0; for_each_sg(sgl, sg, nents, i) { + if (is_pci_p2pdma_page(sg_page(sg))) { + ret = pci_p2pdma_map_segment(&p2pdma_state, dev, sg, + attrs); + if (ret < 0) { + goto out_unmap; + } else if (ret) { + ret = 0; + continue; + } + } + sg->dma_address = dma_direct_map_page(dev, sg_page(sg), sg->offset, sg->length, dir, attrs); if (sg->dma_address == DMA_MAPPING_ERROR)
@@ -411,7 +430,7 @@ int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents, out_unmap: dma_direct_unmap_sg(dev, sgl, i, dir, attrs | DMA_ATTR_SKIP_CPU_SYNC); - return 0; + return ret; } dma_addr_t dma_direct_map_resource(struct device *dev, phys_addr_t paddr,
--
2.20.1
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