| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Logan Gunthorpe | 3228 | 92.97% | 18 | 66.67% |
| Dan J Williams | 106 | 3.05% | 3 | 11.11% |
| Christian König | 88 | 2.53% | 1 | 3.70% |
| Andrew Maier | 24 | 0.69% | 1 | 3.70% |
| Armen Baloyan | 17 | 0.49% | 1 | 3.70% |
| Randy Dunlap | 6 | 0.17% | 1 | 3.70% |
| Christoph Hellwig | 2 | 0.06% | 1 | 3.70% |
| Björn Helgaas | 1 | 0.03% | 1 | 3.70% |
| Total | 3472 | 27 |
// SPDX-License-Identifier: GPL-2.0 /* * PCI Peer 2 Peer DMA support. * * Copyright (c) 2016-2018, Logan Gunthorpe * Copyright (c) 2016-2017, Microsemi Corporation * Copyright (c) 2017, Christoph Hellwig * Copyright (c) 2018, Eideticom Inc. */ #define pr_fmt(fmt) "pci-p2pdma: " fmt #include <linux/ctype.h> #include <linux/pci-p2pdma.h> #include <linux/module.h> #include <linux/slab.h> #include <linux/genalloc.h> #include <linux/memremap.h> #include <linux/percpu-refcount.h> #include <linux/random.h> #include <linux/seq_buf.h> #include <linux/xarray.h> enum pci_p2pdma_map_type { PCI_P2PDMA_MAP_UNKNOWN = 0, PCI_P2PDMA_MAP_NOT_SUPPORTED, PCI_P2PDMA_MAP_BUS_ADDR, PCI_P2PDMA_MAP_THRU_HOST_BRIDGE, }; struct pci_p2pdma { struct gen_pool *pool; bool p2pmem_published; struct xarray map_types; }; struct pci_p2pdma_pagemap { struct dev_pagemap pgmap; struct pci_dev *provider; u64 bus_offset; }; static struct pci_p2pdma_pagemap *to_p2p_pgmap(struct dev_pagemap *pgmap) { return container_of(pgmap, struct pci_p2pdma_pagemap, pgmap); } static ssize_t size_show(struct device *dev, struct device_attribute *attr, char *buf) { struct pci_dev *pdev = to_pci_dev(dev); size_t size = 0; if (pdev->p2pdma->pool) size = gen_pool_size(pdev->p2pdma->pool); return snprintf(buf, PAGE_SIZE, "%zd\n", size); } static DEVICE_ATTR_RO(size); static ssize_t available_show(struct device *dev, struct device_attribute *attr, char *buf) { struct pci_dev *pdev = to_pci_dev(dev); size_t avail = 0; if (pdev->p2pdma->pool) avail = gen_pool_avail(pdev->p2pdma->pool); return snprintf(buf, PAGE_SIZE, "%zd\n", avail); } static DEVICE_ATTR_RO(available); static ssize_t published_show(struct device *dev, struct device_attribute *attr, char *buf) { struct pci_dev *pdev = to_pci_dev(dev); return snprintf(buf, PAGE_SIZE, "%d\n", pdev->p2pdma->p2pmem_published); } static DEVICE_ATTR_RO(published); static struct attribute *p2pmem_attrs[] = { &dev_attr_size.attr, &dev_attr_available.attr, &dev_attr_published.attr, NULL, }; static const struct attribute_group p2pmem_group = { .attrs = p2pmem_attrs, .name = "p2pmem", }; static void pci_p2pdma_release(void *data) { struct pci_dev *pdev = data; struct pci_p2pdma *p2pdma = pdev->p2pdma; if (!p2pdma) return; /* Flush and disable pci_alloc_p2p_mem() */ pdev->p2pdma = NULL; synchronize_rcu(); gen_pool_destroy(p2pdma->pool); sysfs_remove_group(&pdev->dev.kobj, &p2pmem_group); xa_destroy(&p2pdma->map_types); } static int pci_p2pdma_setup(struct pci_dev *pdev) { int error = -ENOMEM; struct pci_p2pdma *p2p; p2p = devm_kzalloc(&pdev->dev, sizeof(*p2p), GFP_KERNEL); if (!p2p) return -ENOMEM; xa_init(&p2p->map_types); p2p->pool = gen_pool_create(PAGE_SHIFT, dev_to_node(&pdev->dev)); if (!p2p->pool) goto out; error = devm_add_action_or_reset(&pdev->dev, pci_p2pdma_release, pdev); if (error) goto out_pool_destroy; pdev->p2pdma = p2p; error = sysfs_create_group(&pdev->dev.kobj, &p2pmem_group); if (error) goto out_pool_destroy; return 0; out_pool_destroy: pdev->p2pdma = NULL; gen_pool_destroy(p2p->pool); out: devm_kfree(&pdev->dev, p2p); return error; } /** * pci_p2pdma_add_resource - add memory for use as p2p memory * @pdev: the device to add the memory to * @bar: PCI BAR to add * @size: size of the memory to add, may be zero to use the whole BAR * @offset: offset into the PCI BAR * * The memory will be given ZONE_DEVICE struct pages so that it may * be used with any DMA request. */ int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size, u64 offset) { struct pci_p2pdma_pagemap *p2p_pgmap; struct dev_pagemap *pgmap; void *addr; int error; if (!(pci_resource_flags(pdev, bar) & IORESOURCE_MEM)) return -EINVAL; if (offset >= pci_resource_len(pdev, bar)) return -EINVAL; if (!size) size = pci_resource_len(pdev, bar) - offset; if (size + offset > pci_resource_len(pdev, bar)) return -EINVAL; if (!pdev->p2pdma) { error = pci_p2pdma_setup(pdev); if (error) return error; } p2p_pgmap = devm_kzalloc(&pdev->dev, sizeof(*p2p_pgmap), GFP_KERNEL); if (!p2p_pgmap) return -ENOMEM; pgmap = &p2p_pgmap->pgmap; pgmap->res.start = pci_resource_start(pdev, bar) + offset; pgmap->res.end = pgmap->res.start + size - 1; pgmap->res.flags = pci_resource_flags(pdev, bar); pgmap->type = MEMORY_DEVICE_PCI_P2PDMA; p2p_pgmap->provider = pdev; p2p_pgmap->bus_offset = pci_bus_address(pdev, bar) - pci_resource_start(pdev, bar); addr = devm_memremap_pages(&pdev->dev, pgmap); if (IS_ERR(addr)) { error = PTR_ERR(addr); goto pgmap_free; } error = gen_pool_add_owner(pdev->p2pdma->pool, (unsigned long)addr, pci_bus_address(pdev, bar) + offset, resource_size(&pgmap->res), dev_to_node(&pdev->dev), pgmap->ref); if (error) goto pages_free; pci_info(pdev, "added peer-to-peer DMA memory %pR\n", &pgmap->res); return 0; pages_free: devm_memunmap_pages(&pdev->dev, pgmap); pgmap_free: devm_kfree(&pdev->dev, pgmap); return error; } EXPORT_SYMBOL_GPL(pci_p2pdma_add_resource); /* * Note this function returns the parent PCI device with a * reference taken. It is the caller's responsibility to drop * the reference. */ static struct pci_dev *find_parent_pci_dev(struct device *dev) { struct device *parent; dev = get_device(dev); while (dev) { if (dev_is_pci(dev)) return to_pci_dev(dev); parent = get_device(dev->parent); put_device(dev); dev = parent; } return NULL; } /* * Check if a PCI bridge has its ACS redirection bits set to redirect P2P * TLPs upstream via ACS. Returns 1 if the packets will be redirected * upstream, 0 otherwise. */ static int pci_bridge_has_acs_redir(struct pci_dev *pdev) { int pos; u16 ctrl; pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_ACS); if (!pos) return 0; pci_read_config_word(pdev, pos + PCI_ACS_CTRL, &ctrl); if (ctrl & (PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_EC)) return 1; return 0; } static void seq_buf_print_bus_devfn(struct seq_buf *buf, struct pci_dev *pdev) { if (!buf) return; seq_buf_printf(buf, "%s;", pci_name(pdev)); } static const struct pci_p2pdma_whitelist_entry { unsigned short vendor; unsigned short device; enum { REQ_SAME_HOST_BRIDGE = 1 << 0, } flags; } pci_p2pdma_whitelist[] = { /* AMD ZEN */ {PCI_VENDOR_ID_AMD, 0x1450, 0}, /* Intel Xeon E5/Core i7 */ {PCI_VENDOR_ID_INTEL, 0x3c00, REQ_SAME_HOST_BRIDGE}, {PCI_VENDOR_ID_INTEL, 0x3c01, REQ_SAME_HOST_BRIDGE}, /* Intel Xeon E7 v3/Xeon E5 v3/Core i7 */ {PCI_VENDOR_ID_INTEL, 0x2f00, REQ_SAME_HOST_BRIDGE}, {PCI_VENDOR_ID_INTEL, 0x2f01, REQ_SAME_HOST_BRIDGE}, /* Intel SkyLake-E */ {PCI_VENDOR_ID_INTEL, 0x2030, 0}, {PCI_VENDOR_ID_INTEL, 0x2031, 0}, {PCI_VENDOR_ID_INTEL, 0x2032, 0}, {PCI_VENDOR_ID_INTEL, 0x2033, 0}, {PCI_VENDOR_ID_INTEL, 0x2020, 0}, {} }; static bool __host_bridge_whitelist(struct pci_host_bridge *host, bool same_host_bridge) { struct pci_dev *root = pci_get_slot(host->bus, PCI_DEVFN(0, 0)); const struct pci_p2pdma_whitelist_entry *entry; unsigned short vendor, device; if (!root) return false; vendor = root->vendor; device = root->device; pci_dev_put(root); for (entry = pci_p2pdma_whitelist; entry->vendor; entry++) { if (vendor != entry->vendor || device != entry->device) continue; if (entry->flags & REQ_SAME_HOST_BRIDGE && !same_host_bridge) return false; return true; } return false; } /* * If we can't find a common upstream bridge take a look at the root * complex and compare it to a whitelist of known good hardware. */ static bool host_bridge_whitelist(struct pci_dev *a, struct pci_dev *b) { struct pci_host_bridge *host_a = pci_find_host_bridge(a->bus); struct pci_host_bridge *host_b = pci_find_host_bridge(b->bus); if (host_a == host_b) return __host_bridge_whitelist(host_a, true); if (__host_bridge_whitelist(host_a, false) && __host_bridge_whitelist(host_b, false)) return true; return false; } static enum pci_p2pdma_map_type __upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client, int *dist, bool *acs_redirects, struct seq_buf *acs_list) { struct pci_dev *a = provider, *b = client, *bb; int dist_a = 0; int dist_b = 0; int acs_cnt = 0; if (acs_redirects) *acs_redirects = false; /* * Note, we don't need to take references to devices returned by * pci_upstream_bridge() seeing we hold a reference to a child * device which will already hold a reference to the upstream bridge. */ while (a) { dist_b = 0; if (pci_bridge_has_acs_redir(a)) { seq_buf_print_bus_devfn(acs_list, a); acs_cnt++; } bb = b; while (bb) { if (a == bb) goto check_b_path_acs; bb = pci_upstream_bridge(bb); dist_b++; } a = pci_upstream_bridge(a); dist_a++; } if (dist) *dist = dist_a + dist_b; return PCI_P2PDMA_MAP_THRU_HOST_BRIDGE; check_b_path_acs: bb = b; while (bb) { if (a == bb) break; if (pci_bridge_has_acs_redir(bb)) { seq_buf_print_bus_devfn(acs_list, bb); acs_cnt++; } bb = pci_upstream_bridge(bb); } if (dist) *dist = dist_a + dist_b; if (acs_cnt) { if (acs_redirects) *acs_redirects = true; return PCI_P2PDMA_MAP_THRU_HOST_BRIDGE; } return PCI_P2PDMA_MAP_BUS_ADDR; } static unsigned long map_types_idx(struct pci_dev *client) { return (pci_domain_nr(client->bus) << 16) | (client->bus->number << 8) | client->devfn; } /* * Find the distance through the nearest common upstream bridge between * two PCI devices. * * If the two devices are the same device then 0 will be returned. * * If there are two virtual functions of the same device behind the same * bridge port then 2 will be returned (one step down to the PCIe switch, * then one step back to the same device). * * In the case where two devices are connected to the same PCIe switch, the * value 4 will be returned. This corresponds to the following PCI tree: * * -+ Root Port * \+ Switch Upstream Port * +-+ Switch Downstream Port * + \- Device A * \-+ Switch Downstream Port * \- Device B * * The distance is 4 because we traverse from Device A through the downstream * port of the switch, to the common upstream port, back up to the second * downstream port and then to Device B. * * Any two devices that cannot communicate using p2pdma will return * PCI_P2PDMA_MAP_NOT_SUPPORTED. * * Any two devices that have a data path that goes through the host bridge * will consult a whitelist. If the host bridges are on the whitelist, * this function will return PCI_P2PDMA_MAP_THRU_HOST_BRIDGE. * * If either bridge is not on the whitelist this function returns * PCI_P2PDMA_MAP_NOT_SUPPORTED. * * If a bridge which has any ACS redirection bits set is in the path, * acs_redirects will be set to true. In this case, a list of all infringing * bridge addresses will be populated in acs_list (assuming it's non-null) * for printk purposes. */ static enum pci_p2pdma_map_type upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client, int *dist, bool *acs_redirects, struct seq_buf *acs_list) { enum pci_p2pdma_map_type map_type; map_type = __upstream_bridge_distance(provider, client, dist, acs_redirects, acs_list); if (map_type == PCI_P2PDMA_MAP_THRU_HOST_BRIDGE) { if (!host_bridge_whitelist(provider, client)) map_type = PCI_P2PDMA_MAP_NOT_SUPPORTED; } if (provider->p2pdma) xa_store(&provider->p2pdma->map_types, map_types_idx(client), xa_mk_value(map_type), GFP_KERNEL); return map_type; } static enum pci_p2pdma_map_type upstream_bridge_distance_warn(struct pci_dev *provider, struct pci_dev *client, int *dist) { struct seq_buf acs_list; bool acs_redirects; int ret; seq_buf_init(&acs_list, kmalloc(PAGE_SIZE, GFP_KERNEL), PAGE_SIZE); if (!acs_list.buffer) return -ENOMEM; ret = upstream_bridge_distance(provider, client, dist, &acs_redirects, &acs_list); if (acs_redirects) { pci_warn(client, "ACS redirect is set between the client and provider (%s)\n", pci_name(provider)); /* Drop final semicolon */ acs_list.buffer[acs_list.len-1] = 0; pci_warn(client, "to disable ACS redirect for this path, add the kernel parameter: pci=disable_acs_redir=%s\n", acs_list.buffer); } if (ret == PCI_P2PDMA_MAP_NOT_SUPPORTED) { pci_warn(client, "cannot be used for peer-to-peer DMA as the client and provider (%s) do not share an upstream bridge or whitelisted host bridge\n", pci_name(provider)); } kfree(acs_list.buffer); return ret; } /** * pci_p2pdma_distance_many - Determine the cumulative distance between * a p2pdma provider and the clients in use. * @provider: p2pdma provider to check against the client list * @clients: array of devices to check (NULL-terminated) * @num_clients: number of clients in the array * @verbose: if true, print warnings for devices when we return -1 * * Returns -1 if any of the clients are not compatible, otherwise returns a * positive number where a lower number is the preferable choice. (If there's * one client that's the same as the provider it will return 0, which is best * choice). * * "compatible" means the provider and the clients are either all behind * the same PCI root port or the host bridges connected to each of the devices * are listed in the 'pci_p2pdma_whitelist'. */ int pci_p2pdma_distance_many(struct pci_dev *provider, struct device **clients, int num_clients, bool verbose) { bool not_supported = false; struct pci_dev *pci_client; int total_dist = 0; int distance; int i, ret; if (num_clients == 0) return -1; for (i = 0; i < num_clients; i++) { if (IS_ENABLED(CONFIG_DMA_VIRT_OPS) && clients[i]->dma_ops == &dma_virt_ops) { if (verbose) dev_warn(clients[i], "cannot be used for peer-to-peer DMA because the driver makes use of dma_virt_ops\n"); return -1; } pci_client = find_parent_pci_dev(clients[i]); if (!pci_client) { if (verbose) dev_warn(clients[i], "cannot be used for peer-to-peer DMA as it is not a PCI device\n"); return -1; } if (verbose) ret = upstream_bridge_distance_warn(provider, pci_client, &distance); else ret = upstream_bridge_distance(provider, pci_client, &distance, NULL, NULL); pci_dev_put(pci_client); if (ret == PCI_P2PDMA_MAP_NOT_SUPPORTED) not_supported = true; if (not_supported && !verbose) break; total_dist += distance; } if (not_supported) return -1; return total_dist; } EXPORT_SYMBOL_GPL(pci_p2pdma_distance_many); /** * pci_has_p2pmem - check if a given PCI device has published any p2pmem * @pdev: PCI device to check */ bool pci_has_p2pmem(struct pci_dev *pdev) { return pdev->p2pdma && pdev->p2pdma->p2pmem_published; } EXPORT_SYMBOL_GPL(pci_has_p2pmem); /** * pci_p2pmem_find - find a peer-to-peer DMA memory device compatible with * the specified list of clients and shortest distance (as determined * by pci_p2pmem_dma()) * @clients: array of devices to check (NULL-terminated) * @num_clients: number of client devices in the list * * If multiple devices are behind the same switch, the one "closest" to the * client devices in use will be chosen first. (So if one of the providers is * the same as one of the clients, that provider will be used ahead of any * other providers that are unrelated). If multiple providers are an equal * distance away, one will be chosen at random. * * Returns a pointer to the PCI device with a reference taken (use pci_dev_put * to return the reference) or NULL if no compatible device is found. The * found provider will also be assigned to the client list. */ struct pci_dev *pci_p2pmem_find_many(struct device **clients, int num_clients) { struct pci_dev *pdev = NULL; int distance; int closest_distance = INT_MAX; struct pci_dev **closest_pdevs; int dev_cnt = 0; const int max_devs = PAGE_SIZE / sizeof(*closest_pdevs); int i; closest_pdevs = kmalloc(PAGE_SIZE, GFP_KERNEL); if (!closest_pdevs) return NULL; while ((pdev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, pdev))) { if (!pci_has_p2pmem(pdev)) continue; distance = pci_p2pdma_distance_many(pdev, clients, num_clients, false); if (distance < 0 || distance > closest_distance) continue; if (distance == closest_distance && dev_cnt >= max_devs) continue; if (distance < closest_distance) { for (i = 0; i < dev_cnt; i++) pci_dev_put(closest_pdevs[i]); dev_cnt = 0; closest_distance = distance; } closest_pdevs[dev_cnt++] = pci_dev_get(pdev); } if (dev_cnt) pdev = pci_dev_get(closest_pdevs[prandom_u32_max(dev_cnt)]); for (i = 0; i < dev_cnt; i++) pci_dev_put(closest_pdevs[i]); kfree(closest_pdevs); return pdev; } EXPORT_SYMBOL_GPL(pci_p2pmem_find_many); /** * pci_alloc_p2p_mem - allocate peer-to-peer DMA memory * @pdev: the device to allocate memory from * @size: number of bytes to allocate * * Returns the allocated memory or NULL on error. */ void *pci_alloc_p2pmem(struct pci_dev *pdev, size_t size) { void *ret = NULL; struct percpu_ref *ref; /* * Pairs with synchronize_rcu() in pci_p2pdma_release() to * ensure pdev->p2pdma is non-NULL for the duration of the * read-lock. */ rcu_read_lock(); if (unlikely(!pdev->p2pdma)) goto out; ret = (void *)gen_pool_alloc_owner(pdev->p2pdma->pool, size, (void **) &ref); if (!ret) goto out; if (unlikely(!percpu_ref_tryget_live(ref))) { gen_pool_free(pdev->p2pdma->pool, (unsigned long) ret, size); ret = NULL; goto out; } out: rcu_read_unlock(); return ret; } EXPORT_SYMBOL_GPL(pci_alloc_p2pmem); /** * pci_free_p2pmem - free peer-to-peer DMA memory * @pdev: the device the memory was allocated from * @addr: address of the memory that was allocated * @size: number of bytes that were allocated */ void pci_free_p2pmem(struct pci_dev *pdev, void *addr, size_t size) { struct percpu_ref *ref; gen_pool_free_owner(pdev->p2pdma->pool, (uintptr_t)addr, size, (void **) &ref); percpu_ref_put(ref); } EXPORT_SYMBOL_GPL(pci_free_p2pmem); /** * pci_virt_to_bus - return the PCI bus address for a given virtual * address obtained with pci_alloc_p2pmem() * @pdev: the device the memory was allocated from * @addr: address of the memory that was allocated */ pci_bus_addr_t pci_p2pmem_virt_to_bus(struct pci_dev *pdev, void *addr) { if (!addr) return 0; if (!pdev->p2pdma) return 0; /* * Note: when we added the memory to the pool we used the PCI * bus address as the physical address. So gen_pool_virt_to_phys() * actually returns the bus address despite the misleading name. */ return gen_pool_virt_to_phys(pdev->p2pdma->pool, (unsigned long)addr); } EXPORT_SYMBOL_GPL(pci_p2pmem_virt_to_bus); /** * pci_p2pmem_alloc_sgl - allocate peer-to-peer DMA memory in a scatterlist * @pdev: the device to allocate memory from * @nents: the number of SG entries in the list * @length: number of bytes to allocate * * Return: %NULL on error or &struct scatterlist pointer and @nents on success */ struct scatterlist *pci_p2pmem_alloc_sgl(struct pci_dev *pdev, unsigned int *nents, u32 length) { struct scatterlist *sg; void *addr; sg = kzalloc(sizeof(*sg), GFP_KERNEL); if (!sg) return NULL; sg_init_table(sg, 1); addr = pci_alloc_p2pmem(pdev, length); if (!addr) goto out_free_sg; sg_set_buf(sg, addr, length); *nents = 1; return sg; out_free_sg: kfree(sg); return NULL; } EXPORT_SYMBOL_GPL(pci_p2pmem_alloc_sgl); /** * pci_p2pmem_free_sgl - free a scatterlist allocated by pci_p2pmem_alloc_sgl() * @pdev: the device to allocate memory from * @sgl: the allocated scatterlist */ void pci_p2pmem_free_sgl(struct pci_dev *pdev, struct scatterlist *sgl) { struct scatterlist *sg; int count; for_each_sg(sgl, sg, INT_MAX, count) { if (!sg) break; pci_free_p2pmem(pdev, sg_virt(sg), sg->length); } kfree(sgl); } EXPORT_SYMBOL_GPL(pci_p2pmem_free_sgl); /** * pci_p2pmem_publish - publish the peer-to-peer DMA memory for use by * other devices with pci_p2pmem_find() * @pdev: the device with peer-to-peer DMA memory to publish * @publish: set to true to publish the memory, false to unpublish it * * Published memory can be used by other PCI device drivers for * peer-2-peer DMA operations. Non-published memory is reserved for * exclusive use of the device driver that registers the peer-to-peer * memory. */ void pci_p2pmem_publish(struct pci_dev *pdev, bool publish) { if (pdev->p2pdma) pdev->p2pdma->p2pmem_published = 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) { struct scatterlist *s; phys_addr_t paddr; int i; /* * p2pdma mappings are not compatible with devices that use * dma_virt_ops. If the upper layers do the right thing * this should never happen because it will be prevented * by the check in pci_p2pdma_distance_many() */ if (WARN_ON_ONCE(IS_ENABLED(CONFIG_DMA_VIRT_OPS) && dev->dma_ops == &dma_virt_ops)) return 0; for_each_sg(sg, s, nents, i) { paddr = sg_phys(s); s->dma_address = paddr - p2p_pgmap->bus_offset; sg_dma_len(s) = s->length; } return nents; } /** * pci_p2pdma_map_sg - map a PCI peer-to-peer scatterlist for DMA * @dev: device doing the DMA request * @sg: scatter list to map * @nents: elements in the scatterlist * @dir: DMA direction * @attrs: DMA attributes passed to dma_map_sg() (if called) * * Scatterlists mapped with this function should be unmapped using * pci_p2pdma_unmap_sg_attrs(). * * Returns the number of SG entries mapped or 0 on error. */ int pci_p2pdma_map_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); struct pci_dev *client; 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); /** * pci_p2pdma_unmap_sg - unmap a PCI peer-to-peer scatterlist that was * mapped with pci_p2pdma_map_sg() * @dev: device doing the DMA request * @sg: scatter list to map * @nents: number of elements returned by pci_p2pdma_map_sg() * @dir: DMA direction * @attrs: DMA attributes passed to dma_unmap_sg() (if called) */ 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); /** * pci_p2pdma_enable_store - parse a configfs/sysfs attribute store * to enable p2pdma * @page: contents of the value to be stored * @p2p_dev: returns the PCI device that was selected to be used * (if one was specified in the stored value) * @use_p2pdma: returns whether to enable p2pdma or not * * Parses an attribute value to decide whether to enable p2pdma. * The value can select a PCI device (using its full BDF device * name) or a boolean (in any format strtobool() accepts). A false * value disables p2pdma, a true value expects the caller * to automatically find a compatible device and specifying a PCI device * expects the caller to use the specific provider. * * pci_p2pdma_enable_show() should be used as the show operation for * the attribute. * * Returns 0 on success */ int pci_p2pdma_enable_store(const char *page, struct pci_dev **p2p_dev, bool *use_p2pdma) { struct device *dev; dev = bus_find_device_by_name(&pci_bus_type, NULL, page); if (dev) { *use_p2pdma = true; *p2p_dev = to_pci_dev(dev); if (!pci_has_p2pmem(*p2p_dev)) { pci_err(*p2p_dev, "PCI device has no peer-to-peer memory: %s\n", page); pci_dev_put(*p2p_dev); return -ENODEV; } return 0; } else if ((page[0] == '0' || page[0] == '1') && !iscntrl(page[1])) { /* * If the user enters a PCI device that doesn't exist * like "0000:01:00.1", we don't want strtobool to think * it's a '0' when it's clearly not what the user wanted. * So we require 0's and 1's to be exactly one character. */ } else if (!strtobool(page, use_p2pdma)) { return 0; } pr_err("No such PCI device: %.*s\n", (int)strcspn(page, "\n"), page); return -ENODEV; } EXPORT_SYMBOL_GPL(pci_p2pdma_enable_store); /** * pci_p2pdma_enable_show - show a configfs/sysfs attribute indicating * whether p2pdma is enabled * @page: contents of the stored value * @p2p_dev: the selected p2p device (NULL if no device is selected) * @use_p2pdma: whether p2pdma has been enabled * * Attributes that use pci_p2pdma_enable_store() should use this function * to show the value of the attribute. * * Returns 0 on success */ ssize_t pci_p2pdma_enable_show(char *page, struct pci_dev *p2p_dev, bool use_p2pdma) { if (!use_p2pdma) return sprintf(page, "0\n"); if (!p2p_dev) return sprintf(page, "1\n"); return sprintf(page, "%s\n", pci_name(p2p_dev)); } EXPORT_SYMBOL_GPL(pci_p2pdma_enable_show);
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