From a25e7962db0d79882c9d32fd2a67a02e79129c0e Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 5 May 2025 10:01:38 +0300 Subject: PCI/P2PDMA: Refactor the p2pdma mapping helpers The current scheme with a single helper to determine the P2P status and map a scatterlist segment force users to always use the map_sg helper to DMA map, which we're trying to get away from because they are very cache inefficient. Refactor the code so that there is a single helper that checks the P2P state for a page, including the result that it is not a P2P page to simplify the callers, and a second one to perform the address translation for a bus mapped P2P transfer that does not depend on the scatterlist structure. Signed-off-by: Christoph Hellwig Reviewed-by: Logan Gunthorpe Acked-by: Bjorn Helgaas Tested-by: Jens Axboe Reviewed-by: Luis Chamberlain Reviewed-by: Lu Baolu Signed-off-by: Leon Romanovsky Signed-off-by: Marek Szyprowski --- include/linux/dma-map-ops.h | 51 ++++++++++++++++++++++++++++++++++++--------- 1 file changed, 41 insertions(+), 10 deletions(-) (limited to 'include/linux/dma-map-ops.h') diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h index e172522cd936..c3086edeccc6 100644 --- a/include/linux/dma-map-ops.h +++ b/include/linux/dma-map-ops.h @@ -443,6 +443,11 @@ enum pci_p2pdma_map_type { */ PCI_P2PDMA_MAP_UNKNOWN = 0, + /* + * Not a PCI P2PDMA transfer. + */ + PCI_P2PDMA_MAP_NONE, + /* * PCI_P2PDMA_MAP_NOT_SUPPORTED: Indicates the transaction will * traverse the host bridge and the host bridge is not in the @@ -471,21 +476,47 @@ enum pci_p2pdma_map_type { struct pci_p2pdma_map_state { struct dev_pagemap *pgmap; - int map; + enum pci_p2pdma_map_type map; u64 bus_off; }; -#ifdef CONFIG_PCI_P2PDMA -enum pci_p2pdma_map_type -pci_p2pdma_map_segment(struct pci_p2pdma_map_state *state, struct device *dev, - struct scatterlist *sg); -#else /* CONFIG_PCI_P2PDMA */ +/* helper for pci_p2pdma_state(), do not use directly */ +void __pci_p2pdma_update_state(struct pci_p2pdma_map_state *state, + struct device *dev, struct page *page); + +/** + * pci_p2pdma_state - check the P2P transfer state of a page + * @state: P2P state structure + * @dev: device to transfer to/from + * @page: page to map + * + * Check if @page is a PCI P2PDMA page, and if yes of what kind. Returns the + * map type, and updates @state with all information needed for a P2P transfer. + */ static inline enum pci_p2pdma_map_type -pci_p2pdma_map_segment(struct pci_p2pdma_map_state *state, struct device *dev, - struct scatterlist *sg) +pci_p2pdma_state(struct pci_p2pdma_map_state *state, struct device *dev, + struct page *page) +{ + if (IS_ENABLED(CONFIG_PCI_P2PDMA) && is_pci_p2pdma_page(page)) { + if (state->pgmap != page_pgmap(page)) + __pci_p2pdma_update_state(state, dev, page); + return state->map; + } + return PCI_P2PDMA_MAP_NONE; +} + +/** + * pci_p2pdma_bus_addr_map - map a PCI_P2PDMA_MAP_BUS_ADDR P2P transfer + * @state: P2P state structure + * @paddr: physical address to map + * + * Map a physically contiguous PCI_P2PDMA_MAP_BUS_ADDR transfer. + */ +static inline dma_addr_t +pci_p2pdma_bus_addr_map(struct pci_p2pdma_map_state *state, phys_addr_t paddr) { - return PCI_P2PDMA_MAP_NOT_SUPPORTED; + WARN_ON_ONCE(state->map != PCI_P2PDMA_MAP_BUS_ADDR); + return paddr + state->bus_off; } -#endif /* CONFIG_PCI_P2PDMA */ #endif /* _LINUX_DMA_MAP_OPS_H */ -- cgit v1.2.3 From ca2c2e4a78c619bcf1c1df29fee5981035f3fcbc Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 5 May 2025 10:01:39 +0300 Subject: dma-mapping: move the PCI P2PDMA mapping helpers to pci-p2pdma.h To support the upcoming non-scatterlist mapping helpers, we need to go back to have them called outside of the DMA API. Thus move them out of dma-map-ops.h, which is only for DMA API implementations to pci-p2pdma.h, which is for driver use. Note that the core helper is still not exported as the mapping is expected to be done only by very highlevel subsystem code at least for now. Signed-off-by: Christoph Hellwig Reviewed-by: Logan Gunthorpe Acked-by: Bjorn Helgaas Tested-by: Jens Axboe Reviewed-by: Luis Chamberlain Reviewed-by: Lu Baolu Signed-off-by: Leon Romanovsky Signed-off-by: Marek Szyprowski --- drivers/iommu/dma-iommu.c | 1 + include/linux/dma-map-ops.h | 85 --------------------------------------------- include/linux/pci-p2pdma.h | 85 +++++++++++++++++++++++++++++++++++++++++++++ kernel/dma/direct.c | 1 + 4 files changed, 87 insertions(+), 85 deletions(-) (limited to 'include/linux/dma-map-ops.h') diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index a8f9fd93e150..145606498b4c 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -27,6 +27,7 @@ #include #include #include +#include #include #include #include diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h index c3086edeccc6..f48e5fb88bd5 100644 --- a/include/linux/dma-map-ops.h +++ b/include/linux/dma-map-ops.h @@ -434,89 +434,4 @@ static inline void debug_dma_dump_mappings(struct device *dev) #endif /* CONFIG_DMA_API_DEBUG */ extern const struct dma_map_ops dma_dummy_ops; - -enum pci_p2pdma_map_type { - /* - * PCI_P2PDMA_MAP_UNKNOWN: Used internally for indicating the mapping - * type hasn't been calculated yet. Functions that return this enum - * never return this value. - */ - PCI_P2PDMA_MAP_UNKNOWN = 0, - - /* - * Not a PCI P2PDMA transfer. - */ - PCI_P2PDMA_MAP_NONE, - - /* - * PCI_P2PDMA_MAP_NOT_SUPPORTED: Indicates the transaction will - * traverse the host bridge and the host bridge is not in the - * allowlist. DMA Mapping routines should return an error when - * this is returned. - */ - PCI_P2PDMA_MAP_NOT_SUPPORTED, - - /* - * PCI_P2PDMA_BUS_ADDR: Indicates that two devices can talk to - * each other directly through a PCI switch and the transaction will - * not traverse the host bridge. Such a mapping should program - * the DMA engine with PCI bus addresses. - */ - PCI_P2PDMA_MAP_BUS_ADDR, - - /* - * PCI_P2PDMA_MAP_THRU_HOST_BRIDGE: Indicates two devices can talk - * to each other, but the transaction traverses a host bridge on the - * allowlist. In this case, a normal mapping either with CPU physical - * addresses (in the case of dma-direct) or IOVA addresses (in the - * case of IOMMUs) should be used to program the DMA engine. - */ - PCI_P2PDMA_MAP_THRU_HOST_BRIDGE, -}; - -struct pci_p2pdma_map_state { - struct dev_pagemap *pgmap; - enum pci_p2pdma_map_type map; - u64 bus_off; -}; - -/* helper for pci_p2pdma_state(), do not use directly */ -void __pci_p2pdma_update_state(struct pci_p2pdma_map_state *state, - struct device *dev, struct page *page); - -/** - * pci_p2pdma_state - check the P2P transfer state of a page - * @state: P2P state structure - * @dev: device to transfer to/from - * @page: page to map - * - * Check if @page is a PCI P2PDMA page, and if yes of what kind. Returns the - * map type, and updates @state with all information needed for a P2P transfer. - */ -static inline enum pci_p2pdma_map_type -pci_p2pdma_state(struct pci_p2pdma_map_state *state, struct device *dev, - struct page *page) -{ - if (IS_ENABLED(CONFIG_PCI_P2PDMA) && is_pci_p2pdma_page(page)) { - if (state->pgmap != page_pgmap(page)) - __pci_p2pdma_update_state(state, dev, page); - return state->map; - } - return PCI_P2PDMA_MAP_NONE; -} - -/** - * pci_p2pdma_bus_addr_map - map a PCI_P2PDMA_MAP_BUS_ADDR P2P transfer - * @state: P2P state structure - * @paddr: physical address to map - * - * Map a physically contiguous PCI_P2PDMA_MAP_BUS_ADDR transfer. - */ -static inline dma_addr_t -pci_p2pdma_bus_addr_map(struct pci_p2pdma_map_state *state, phys_addr_t paddr) -{ - WARN_ON_ONCE(state->map != PCI_P2PDMA_MAP_BUS_ADDR); - return paddr + state->bus_off; -} - #endif /* _LINUX_DMA_MAP_OPS_H */ diff --git a/include/linux/pci-p2pdma.h b/include/linux/pci-p2pdma.h index 2c07aa6b7665..075c20b161d9 100644 --- a/include/linux/pci-p2pdma.h +++ b/include/linux/pci-p2pdma.h @@ -104,4 +104,89 @@ static inline struct pci_dev *pci_p2pmem_find(struct device *client) return pci_p2pmem_find_many(&client, 1); } +enum pci_p2pdma_map_type { + /* + * PCI_P2PDMA_MAP_UNKNOWN: Used internally as an initial state before + * the mapping type has been calculated. Exported routines for the API + * will never return this value. + */ + PCI_P2PDMA_MAP_UNKNOWN = 0, + + /* + * Not a PCI P2PDMA transfer. + */ + PCI_P2PDMA_MAP_NONE, + + /* + * PCI_P2PDMA_MAP_NOT_SUPPORTED: Indicates the transaction will + * traverse the host bridge and the host bridge is not in the + * allowlist. DMA Mapping routines should return an error when + * this is returned. + */ + PCI_P2PDMA_MAP_NOT_SUPPORTED, + + /* + * PCI_P2PDMA_MAP_BUS_ADDR: Indicates that two devices can talk to + * each other directly through a PCI switch and the transaction will + * not traverse the host bridge. Such a mapping should program + * the DMA engine with PCI bus addresses. + */ + PCI_P2PDMA_MAP_BUS_ADDR, + + /* + * PCI_P2PDMA_MAP_THRU_HOST_BRIDGE: Indicates two devices can talk + * to each other, but the transaction traverses a host bridge on the + * allowlist. In this case, a normal mapping either with CPU physical + * addresses (in the case of dma-direct) or IOVA addresses (in the + * case of IOMMUs) should be used to program the DMA engine. + */ + PCI_P2PDMA_MAP_THRU_HOST_BRIDGE, +}; + +struct pci_p2pdma_map_state { + struct dev_pagemap *pgmap; + enum pci_p2pdma_map_type map; + u64 bus_off; +}; + +/* helper for pci_p2pdma_state(), do not use directly */ +void __pci_p2pdma_update_state(struct pci_p2pdma_map_state *state, + struct device *dev, struct page *page); + +/** + * pci_p2pdma_state - check the P2P transfer state of a page + * @state: P2P state structure + * @dev: device to transfer to/from + * @page: page to map + * + * Check if @page is a PCI P2PDMA page, and if yes of what kind. Returns the + * map type, and updates @state with all information needed for a P2P transfer. + */ +static inline enum pci_p2pdma_map_type +pci_p2pdma_state(struct pci_p2pdma_map_state *state, struct device *dev, + struct page *page) +{ + if (IS_ENABLED(CONFIG_PCI_P2PDMA) && is_pci_p2pdma_page(page)) { + if (state->pgmap != page_pgmap(page)) + __pci_p2pdma_update_state(state, dev, page); + return state->map; + } + return PCI_P2PDMA_MAP_NONE; +} + +/** + * pci_p2pdma_bus_addr_map - Translate a physical address to a bus address + * for a PCI_P2PDMA_MAP_BUS_ADDR transfer. + * @state: P2P state structure + * @paddr: physical address to map + * + * Map a physically contiguous PCI_P2PDMA_MAP_BUS_ADDR transfer. + */ +static inline dma_addr_t +pci_p2pdma_bus_addr_map(struct pci_p2pdma_map_state *state, phys_addr_t paddr) +{ + WARN_ON_ONCE(state->map != PCI_P2PDMA_MAP_BUS_ADDR); + return paddr + state->bus_off; +} + #endif /* _LINUX_PCI_P2P_H */ diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index cec43cd5ed62..24c359d9c879 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -13,6 +13,7 @@ #include #include #include +#include #include "direct.h" /* -- cgit v1.2.3