char *buf)
{
struct pci_dev *pdev = to_pci_dev(dev);
+ struct pci_p2pdma *p2pdma;
size_t size = 0;
- if (pdev->p2pdma->pool)
- size = gen_pool_size(pdev->p2pdma->pool);
+ rcu_read_lock();
+ p2pdma = rcu_dereference(pdev->p2pdma);
+ if (p2pdma && p2pdma->pool)
+ size = gen_pool_size(p2pdma->pool);
+ rcu_read_unlock();
return sysfs_emit(buf, "%zd\n", size);
}
char *buf)
{
struct pci_dev *pdev = to_pci_dev(dev);
+ struct pci_p2pdma *p2pdma;
size_t avail = 0;
- if (pdev->p2pdma->pool)
- avail = gen_pool_avail(pdev->p2pdma->pool);
+ rcu_read_lock();
+ p2pdma = rcu_dereference(pdev->p2pdma);
+ if (p2pdma && p2pdma->pool)
+ avail = gen_pool_avail(p2pdma->pool);
+ rcu_read_unlock();
return sysfs_emit(buf, "%zd\n", avail);
}
char *buf)
{
struct pci_dev *pdev = to_pci_dev(dev);
+ struct pci_p2pdma *p2pdma;
+ bool published = false;
- return sysfs_emit(buf, "%d\n", pdev->p2pdma->p2pmem_published);
+ rcu_read_lock();
+ p2pdma = rcu_dereference(pdev->p2pdma);
+ if (p2pdma)
+ published = p2pdma->p2pmem_published;
+ rcu_read_unlock();
+
+ return sysfs_emit(buf, "%d\n", published);
}
static DEVICE_ATTR_RO(published);
static void pci_p2pdma_release(void *data)
{
struct pci_dev *pdev = data;
- struct pci_p2pdma *p2pdma = pdev->p2pdma;
+ struct pci_p2pdma *p2pdma;
+ p2pdma = rcu_dereference_protected(pdev->p2pdma, 1);
if (!p2pdma)
return;
if (error)
goto out_pool_destroy;
- pdev->p2pdma = p2p;
-
error = sysfs_create_group(&pdev->dev.kobj, &p2pmem_group);
if (error)
goto out_pool_destroy;
+ rcu_assign_pointer(pdev->p2pdma, p2p);
return 0;
out_pool_destroy:
- pdev->p2pdma = NULL;
gen_pool_destroy(p2p->pool);
out:
devm_kfree(&pdev->dev, p2p);
{
struct pci_p2pdma_pagemap *p2p_pgmap;
struct dev_pagemap *pgmap;
+ struct pci_p2pdma *p2pdma;
void *addr;
int error;
goto pgmap_free;
}
- error = gen_pool_add_owner(pdev->p2pdma->pool, (unsigned long)addr,
+ p2pdma = rcu_dereference_protected(pdev->p2pdma, 1);
+ error = gen_pool_add_owner(p2pdma->pool, (unsigned long)addr,
pci_bus_address(pdev, bar) + offset,
range_len(&pgmap->range), dev_to_node(&pdev->dev),
pgmap->ref);
{}
};
+/*
+ * This lookup function tries to find the PCI device corresponding to a given
+ * host bridge.
+ *
+ * It assumes the host bridge device is the first PCI device in the
+ * bus->devices list and that the devfn is 00.0. These assumptions should hold
+ * for all the devices in the whitelist above.
+ *
+ * This function is equivalent to pci_get_slot(host->bus, 0), however it does
+ * not take the pci_bus_sem lock seeing __host_bridge_whitelist() must not
+ * sleep.
+ *
+ * For this to be safe, the caller should hold a reference to a device on the
+ * bridge, which should ensure the host_bridge device will not be freed
+ * or removed from the head of the devices list.
+ */
+static struct pci_dev *pci_host_bridge_dev(struct pci_host_bridge *host)
+{
+ struct pci_dev *root;
+
+ root = list_first_entry_or_null(&host->bus->devices,
+ struct pci_dev, bus_list);
+
+ if (!root)
+ return NULL;
+ if (root->devfn != PCI_DEVFN(0, 0))
+ return NULL;
+
+ return root;
+}
+
static bool __host_bridge_whitelist(struct pci_host_bridge *host,
- bool same_host_bridge)
+ bool same_host_bridge, bool warn)
{
- struct pci_dev *root = pci_get_slot(host->bus, PCI_DEVFN(0, 0));
+ struct pci_dev *root = pci_host_bridge_dev(host);
const struct pci_p2pdma_whitelist_entry *entry;
unsigned short vendor, device;
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)
return true;
}
+ if (warn)
+ pci_warn(root, "Host bridge not in P2PDMA whitelist: %04x:%04x\n",
+ vendor, device);
+
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)
+static bool host_bridge_whitelist(struct pci_dev *a, struct pci_dev *b,
+ bool warn)
{
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);
+ return __host_bridge_whitelist(host_a, true, warn);
- if (__host_bridge_whitelist(host_a, false) &&
- __host_bridge_whitelist(host_b, false))
+ if (__host_bridge_whitelist(host_a, false, warn) &&
+ __host_bridge_whitelist(host_b, false, warn))
return true;
return false;
}
+static unsigned long map_types_idx(struct pci_dev *client)
+{
+ return (pci_domain_nr(client->bus) << 16) |
+ (client->bus->number << 8) | client->devfn;
+}
+
+/*
+ * Calculate the P2PDMA mapping type and distance between two PCI devices.
+ *
+ * If the two devices are the same PCI function, return
+ * PCI_P2PDMA_MAP_BUS_ADDR and a distance of 0.
+ *
+ * If they are two functions of the same device, return
+ * PCI_P2PDMA_MAP_BUS_ADDR and a distance of 2 (one hop up to the bridge,
+ * then one hop back down to another function of the same device).
+ *
+ * In the case where two devices are connected to the same PCIe switch,
+ * return a distance of 4. This corresponds to the following PCI tree:
+ *
+ * -+ Root Port
+ * \+ Switch Upstream Port
+ * +-+ Switch Downstream Port 0
+ * + \- Device A
+ * \-+ Switch Downstream Port 1
+ * \- Device B
+ *
+ * The distance is 4 because we traverse from Device A to Downstream Port 0
+ * to the common Switch Upstream Port, back down to Downstream Port 1 and
+ * then to Device B. The mapping type returned depends on the ACS
+ * redirection setting of the ports along the path.
+ *
+ * If ACS redirect is set on any port in the path, traffic between the
+ * devices will go through the host bridge, so return
+ * PCI_P2PDMA_MAP_THRU_HOST_BRIDGE; otherwise return
+ * PCI_P2PDMA_MAP_BUS_ADDR.
+ *
+ * Any two devices that have a data path that goes through the host bridge
+ * will consult a whitelist. If the host bridge is in the whitelist, return
+ * PCI_P2PDMA_MAP_THRU_HOST_BRIDGE with the distance set to the number of
+ * ports per above. If the device is not in the whitelist, return
+ * PCI_P2PDMA_MAP_NOT_SUPPORTED.
+ */
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)
+calc_map_type_and_dist(struct pci_dev *provider, struct pci_dev *client,
+ int *dist, bool verbose)
{
+ enum pci_p2pdma_map_type map_type = PCI_P2PDMA_MAP_THRU_HOST_BRIDGE;
struct pci_dev *a = provider, *b = client, *bb;
+ bool acs_redirects = false;
+ struct pci_p2pdma *p2pdma;
+ struct seq_buf acs_list;
+ int acs_cnt = 0;
int dist_a = 0;
int dist_b = 0;
- int acs_cnt = 0;
+ char buf[128];
- if (acs_redirects)
- *acs_redirects = false;
+ seq_buf_init(&acs_list, buf, sizeof(buf));
/*
* 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);
+ seq_buf_print_bus_devfn(&acs_list, a);
acs_cnt++;
}
dist_a++;
}
- if (dist)
- *dist = dist_a + dist_b;
-
- return PCI_P2PDMA_MAP_THRU_HOST_BRIDGE;
+ *dist = dist_a + dist_b;
+ goto map_through_host_bridge;
check_b_path_acs:
bb = b;
break;
if (pci_bridge_has_acs_redir(bb)) {
- seq_buf_print_bus_devfn(acs_list, 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);
+ *dist = dist_a + dist_b;
- if (map_type == PCI_P2PDMA_MAP_THRU_HOST_BRIDGE) {
- if (!cpu_supports_p2pdma() &&
- !host_bridge_whitelist(provider, client))
- map_type = PCI_P2PDMA_MAP_NOT_SUPPORTED;
+ if (!acs_cnt) {
+ map_type = PCI_P2PDMA_MAP_BUS_ADDR;
+ goto done;
}
- 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) {
+ if (verbose) {
+ acs_list.buffer[acs_list.len-1] = 0; /* drop final semicolon */
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);
}
+ acs_redirects = true;
- 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));
+map_through_host_bridge:
+ if (!cpu_supports_p2pdma() &&
+ !host_bridge_whitelist(provider, client, acs_redirects)) {
+ if (verbose)
+ 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));
+ map_type = PCI_P2PDMA_MAP_NOT_SUPPORTED;
}
-
- kfree(acs_list.buffer);
-
- return ret;
+done:
+ rcu_read_lock();
+ p2pdma = rcu_dereference(provider->p2pdma);
+ if (p2pdma)
+ xa_store(&p2pdma->map_types, map_types_idx(client),
+ xa_mk_value(map_type), GFP_KERNEL);
+ rcu_read_unlock();
+ return map_type;
}
/**
int pci_p2pdma_distance_many(struct pci_dev *provider, struct device **clients,
int num_clients, bool verbose)
{
+ enum pci_p2pdma_map_type map;
bool not_supported = false;
struct pci_dev *pci_client;
int total_dist = 0;
- int distance;
- int i, ret;
+ int i, distance;
if (num_clients == 0)
return -1;
return -1;
}
- if (verbose)
- ret = upstream_bridge_distance_warn(provider,
- pci_client, &distance);
- else
- ret = upstream_bridge_distance(provider, pci_client,
- &distance, NULL, NULL);
+ map = calc_map_type_and_dist(provider, pci_client, &distance,
+ verbose);
pci_dev_put(pci_client);
- if (ret == PCI_P2PDMA_MAP_NOT_SUPPORTED)
+ if (map == PCI_P2PDMA_MAP_NOT_SUPPORTED)
not_supported = true;
if (not_supported && !verbose)
*/
bool pci_has_p2pmem(struct pci_dev *pdev)
{
- return pdev->p2pdma && pdev->p2pdma->p2pmem_published;
+ struct pci_p2pdma *p2pdma;
+ bool res;
+
+ rcu_read_lock();
+ p2pdma = rcu_dereference(pdev->p2pdma);
+ res = p2pdma && p2pdma->p2pmem_published;
+ rcu_read_unlock();
+
+ return res;
}
EXPORT_SYMBOL_GPL(pci_has_p2pmem);
{
void *ret = NULL;
struct percpu_ref *ref;
+ struct pci_p2pdma *p2pdma;
/*
* Pairs with synchronize_rcu() in pci_p2pdma_release() to
* read-lock.
*/
rcu_read_lock();
- if (unlikely(!pdev->p2pdma))
+ p2pdma = rcu_dereference(pdev->p2pdma);
+ if (unlikely(!p2pdma))
goto out;
- ret = (void *)gen_pool_alloc_owner(pdev->p2pdma->pool, size,
- (void **) &ref);
+ ret = (void *)gen_pool_alloc_owner(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);
+ gen_pool_free(p2pdma->pool, (unsigned long) ret, size);
ret = NULL;
goto out;
}
void pci_free_p2pmem(struct pci_dev *pdev, void *addr, size_t size)
{
struct percpu_ref *ref;
+ struct pci_p2pdma *p2pdma = rcu_dereference_protected(pdev->p2pdma, 1);
- gen_pool_free_owner(pdev->p2pdma->pool, (uintptr_t)addr, size,
+ gen_pool_free_owner(p2pdma->pool, (uintptr_t)addr, size,
(void **) &ref);
percpu_ref_put(ref);
}
*/
pci_bus_addr_t pci_p2pmem_virt_to_bus(struct pci_dev *pdev, void *addr)
{
+ struct pci_p2pdma *p2pdma;
+
if (!addr)
return 0;
- if (!pdev->p2pdma)
+
+ p2pdma = rcu_dereference_protected(pdev->p2pdma, 1);
+ if (!p2pdma)
return 0;
/*
* 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);
+ return gen_pool_virt_to_phys(p2pdma->pool, (unsigned long)addr);
}
EXPORT_SYMBOL_GPL(pci_p2pmem_virt_to_bus);
*/
void pci_p2pmem_publish(struct pci_dev *pdev, bool publish)
{
- if (pdev->p2pdma)
- pdev->p2pdma->p2pmem_published = publish;
+ struct pci_p2pdma *p2pdma;
+
+ rcu_read_lock();
+ p2pdma = rcu_dereference(pdev->p2pdma);
+ if (p2pdma)
+ p2pdma->p2pmem_published = publish;
+ rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(pci_p2pmem_publish);
-static enum pci_p2pdma_map_type pci_p2pdma_map_type(struct pci_dev *provider,
- struct pci_dev *client)
+static enum pci_p2pdma_map_type pci_p2pdma_map_type(struct dev_pagemap *pgmap,
+ 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 *client;
+ struct pci_p2pdma *p2pdma;
+
if (!provider->p2pdma)
return PCI_P2PDMA_MAP_NOT_SUPPORTED;
- return xa_to_value(xa_load(&provider->p2pdma->map_types,
- map_types_idx(client)));
+ if (!dev_is_pci(dev))
+ return PCI_P2PDMA_MAP_NOT_SUPPORTED;
+
+ client = to_pci_dev(dev);
+
+ rcu_read_lock();
+ p2pdma = rcu_dereference(provider->p2pdma);
+
+ if (p2pdma)
+ type = xa_to_value(xa_load(&p2pdma->map_types,
+ map_types_idx(client)));
+ rcu_read_unlock();
+ return type;
}
static int __pci_p2pdma_map_sg(struct pci_p2pdma_pagemap *p2p_pgmap,
{
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)) {
+ switch (pci_p2pdma_map_type(sg_page(sg)->pgmap, dev)) {
case PCI_P2PDMA_MAP_THRU_HOST_BRIDGE:
return dma_map_sg_attrs(dev, sg, nents, dir, attrs);
case PCI_P2PDMA_MAP_BUS_ADDR:
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);
+ map_type = pci_p2pdma_map_type(sg_page(sg)->pgmap, dev);
if (map_type == PCI_P2PDMA_MAP_THRU_HOST_BRIDGE)
dma_unmap_sg_attrs(dev, sg, nents, dir, attrs);
projects / linux-2.6-microblaze.git / commitdiff