From: Leon Romanovsky leonro@nvidia.com
Extract the core P2PDMA provider information (device owner and bus offset) from the dev_pagemap into a dedicated p2pdma_provider structure. This creates a cleaner separation between the memory management layer and the P2PDMA functionality.
The new p2pdma_provider structure contains: - owner: pointer to the providing device - bus_offset: computed offset for non-host transactions
This refactoring simplifies the P2PDMA state management by removing the need to access pgmap internals directly. The pci_p2pdma_map_state now stores a pointer to the provider instead of the pgmap, making the API more explicit and easier to understand.
Signed-off-by: Jason Gunthorpe jgg@nvidia.com Signed-off-by: Leon Romanovsky leonro@nvidia.com --- drivers/pci/p2pdma.c | 42 +++++++++++++++++++++----------------- include/linux/pci-p2pdma.h | 18 ++++++++++++---- 2 files changed, 37 insertions(+), 23 deletions(-)
diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index fe347ed7fd8f4..5a310026bd24f 100644 --- a/drivers/pci/p2pdma.c +++ b/drivers/pci/p2pdma.c @@ -28,9 +28,8 @@ struct pci_p2pdma { };
struct pci_p2pdma_pagemap { - struct pci_dev *provider; - u64 bus_offset; struct dev_pagemap pgmap; + struct p2pdma_provider mem; };
static struct pci_p2pdma_pagemap *to_p2p_pgmap(struct dev_pagemap *pgmap) @@ -204,8 +203,8 @@ static void p2pdma_page_free(struct page *page) { struct pci_p2pdma_pagemap *pgmap = to_p2p_pgmap(page_pgmap(page)); /* safe to dereference while a reference is held to the percpu ref */ - struct pci_p2pdma *p2pdma = - rcu_dereference_protected(pgmap->provider->p2pdma, 1); + struct pci_p2pdma *p2pdma = rcu_dereference_protected( + to_pci_dev(pgmap->mem.owner)->p2pdma, 1); struct percpu_ref *ref;
gen_pool_free_owner(p2pdma->pool, (uintptr_t)page_to_virt(page), @@ -270,14 +269,15 @@ static int pci_p2pdma_setup(struct pci_dev *pdev)
static void pci_p2pdma_unmap_mappings(void *data) { - struct pci_dev *pdev = data; + struct pci_p2pdma_pagemap *p2p_pgmap = data;
/* * Removing the alloc attribute from sysfs will call * unmap_mapping_range() on the inode, teardown any existing userspace * mappings and prevent new ones from being created. */ - sysfs_remove_file_from_group(&pdev->dev.kobj, &p2pmem_alloc_attr.attr, + sysfs_remove_file_from_group(&p2p_pgmap->mem.owner->kobj, + &p2pmem_alloc_attr.attr, p2pmem_group.name); }
@@ -328,10 +328,9 @@ int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size, pgmap->nr_range = 1; pgmap->type = MEMORY_DEVICE_PCI_P2PDMA; pgmap->ops = &p2pdma_pgmap_ops; - - p2p_pgmap->provider = pdev; - p2p_pgmap->bus_offset = pci_bus_address(pdev, bar) - - pci_resource_start(pdev, bar); + p2p_pgmap->mem.owner = &pdev->dev; + p2p_pgmap->mem.bus_offset = + pci_bus_address(pdev, bar) - pci_resource_start(pdev, bar);
addr = devm_memremap_pages(&pdev->dev, pgmap); if (IS_ERR(addr)) { @@ -340,7 +339,7 @@ int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size, }
error = devm_add_action_or_reset(&pdev->dev, pci_p2pdma_unmap_mappings, - pdev); + p2p_pgmap); if (error) goto pages_free;
@@ -973,16 +972,16 @@ 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 dev_pagemap *pgmap, - struct device *dev) +static enum pci_p2pdma_map_type +pci_p2pdma_map_type(struct p2pdma_provider *provider, struct device *dev) { enum pci_p2pdma_map_type type = PCI_P2PDMA_MAP_NOT_SUPPORTED; - struct pci_dev *provider = to_p2p_pgmap(pgmap)->provider; + struct pci_dev *pdev = to_pci_dev(provider->owner); struct pci_dev *client; struct pci_p2pdma *p2pdma; int dist;
- if (!provider->p2pdma) + if (!pdev->p2pdma) return PCI_P2PDMA_MAP_NOT_SUPPORTED;
if (!dev_is_pci(dev)) @@ -991,7 +990,7 @@ static enum pci_p2pdma_map_type pci_p2pdma_map_type(struct dev_pagemap *pgmap, client = to_pci_dev(dev);
rcu_read_lock(); - p2pdma = rcu_dereference(provider->p2pdma); + p2pdma = rcu_dereference(pdev->p2pdma);
if (p2pdma) type = xa_to_value(xa_load(&p2pdma->map_types, @@ -999,7 +998,7 @@ static enum pci_p2pdma_map_type pci_p2pdma_map_type(struct dev_pagemap *pgmap, rcu_read_unlock();
if (type == PCI_P2PDMA_MAP_UNKNOWN) - return calc_map_type_and_dist(provider, client, &dist, true); + return calc_map_type_and_dist(pdev, client, &dist, true);
return type; } @@ -1007,8 +1006,13 @@ static enum pci_p2pdma_map_type pci_p2pdma_map_type(struct dev_pagemap *pgmap, void __pci_p2pdma_update_state(struct pci_p2pdma_map_state *state, struct device *dev, struct page *page) { - state->pgmap = page_pgmap(page); - state->map = pci_p2pdma_map_type(state->pgmap, dev); + struct pci_p2pdma_pagemap *p2p_pgmap = to_p2p_pgmap(page_pgmap(page)); + + if (state->mem == &p2p_pgmap->mem) + return; + + state->mem = &p2p_pgmap->mem; + state->map = pci_p2pdma_map_type(&p2p_pgmap->mem, dev); }
/** diff --git a/include/linux/pci-p2pdma.h b/include/linux/pci-p2pdma.h index b502fc8b49bf9..27a2c399f47da 100644 --- a/include/linux/pci-p2pdma.h +++ b/include/linux/pci-p2pdma.h @@ -16,6 +16,16 @@ struct block_device; struct scatterlist;
+/** + * struct p2pdma_provider + * + * A p2pdma provider is a range of MMIO address space available to the CPU. + */ +struct p2pdma_provider { + struct device *owner; + u64 bus_offset; +}; + #ifdef CONFIG_PCI_P2PDMA int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size, u64 offset); @@ -144,10 +154,11 @@ enum pci_p2pdma_map_type { };
struct pci_p2pdma_map_state { - struct dev_pagemap *pgmap; + struct p2pdma_provider *mem; enum pci_p2pdma_map_type map; };
+ /* 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); @@ -166,8 +177,7 @@ 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); + __pci_p2pdma_update_state(state, dev, page); return state->map; } return PCI_P2PDMA_MAP_NONE; @@ -185,7 +195,7 @@ 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 + to_p2p_pgmap(state->pgmap)->bus_offsetf; + return paddr + state->mem->bus_offset; }
#endif /* _LINUX_PCI_P2P_H */