diff options
Diffstat (limited to 'drivers/dax/bus.c')
| -rw-r--r-- | drivers/dax/bus.c | 1487 |
1 files changed, 1487 insertions, 0 deletions
diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c new file mode 100644 index 0000000000..0ee96e6fc4 --- /dev/null +++ b/drivers/dax/bus.c @@ -0,0 +1,1487 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright(c) 2017-2018 Intel Corporation. All rights reserved. */ +#include <linux/memremap.h> +#include <linux/device.h> +#include <linux/mutex.h> +#include <linux/list.h> +#include <linux/slab.h> +#include <linux/dax.h> +#include <linux/io.h> +#include "dax-private.h" +#include "bus.h" + +static DEFINE_MUTEX(dax_bus_lock); + +#define DAX_NAME_LEN 30 +struct dax_id { + struct list_head list; + char dev_name[DAX_NAME_LEN]; +}; + +static int dax_bus_uevent(const struct device *dev, struct kobj_uevent_env *env) +{ + /* + * We only ever expect to handle device-dax instances, i.e. the + * @type argument to MODULE_ALIAS_DAX_DEVICE() is always zero + */ + return add_uevent_var(env, "MODALIAS=" DAX_DEVICE_MODALIAS_FMT, 0); +} + +static struct dax_device_driver *to_dax_drv(struct device_driver *drv) +{ + return container_of(drv, struct dax_device_driver, drv); +} + +static struct dax_id *__dax_match_id(struct dax_device_driver *dax_drv, + const char *dev_name) +{ + struct dax_id *dax_id; + + lockdep_assert_held(&dax_bus_lock); + + list_for_each_entry(dax_id, &dax_drv->ids, list) + if (sysfs_streq(dax_id->dev_name, dev_name)) + return dax_id; + return NULL; +} + +static int dax_match_id(struct dax_device_driver *dax_drv, struct device *dev) +{ + int match; + + mutex_lock(&dax_bus_lock); + match = !!__dax_match_id(dax_drv, dev_name(dev)); + mutex_unlock(&dax_bus_lock); + + return match; +} + +static int dax_match_type(struct dax_device_driver *dax_drv, struct device *dev) +{ + enum dax_driver_type type = DAXDRV_DEVICE_TYPE; + struct dev_dax *dev_dax = to_dev_dax(dev); + + if (dev_dax->region->res.flags & IORESOURCE_DAX_KMEM) + type = DAXDRV_KMEM_TYPE; + + if (dax_drv->type == type) + return 1; + + /* default to device mode if dax_kmem is disabled */ + if (dax_drv->type == DAXDRV_DEVICE_TYPE && + !IS_ENABLED(CONFIG_DEV_DAX_KMEM)) + return 1; + + return 0; +} + +enum id_action { + ID_REMOVE, + ID_ADD, +}; + +static ssize_t do_id_store(struct device_driver *drv, const char *buf, + size_t count, enum id_action action) +{ + struct dax_device_driver *dax_drv = to_dax_drv(drv); + unsigned int region_id, id; + char devname[DAX_NAME_LEN]; + struct dax_id *dax_id; + ssize_t rc = count; + int fields; + + fields = sscanf(buf, "dax%d.%d", ®ion_id, &id); + if (fields != 2) + return -EINVAL; + sprintf(devname, "dax%d.%d", region_id, id); + if (!sysfs_streq(buf, devname)) + return -EINVAL; + + mutex_lock(&dax_bus_lock); + dax_id = __dax_match_id(dax_drv, buf); + if (!dax_id) { + if (action == ID_ADD) { + dax_id = kzalloc(sizeof(*dax_id), GFP_KERNEL); + if (dax_id) { + strncpy(dax_id->dev_name, buf, DAX_NAME_LEN); + list_add(&dax_id->list, &dax_drv->ids); + } else + rc = -ENOMEM; + } + } else if (action == ID_REMOVE) { + list_del(&dax_id->list); + kfree(dax_id); + } + mutex_unlock(&dax_bus_lock); + + if (rc < 0) + return rc; + if (action == ID_ADD) + rc = driver_attach(drv); + if (rc) + return rc; + return count; +} + +static ssize_t new_id_store(struct device_driver *drv, const char *buf, + size_t count) +{ + return do_id_store(drv, buf, count, ID_ADD); +} +static DRIVER_ATTR_WO(new_id); + +static ssize_t remove_id_store(struct device_driver *drv, const char *buf, + size_t count) +{ + return do_id_store(drv, buf, count, ID_REMOVE); +} +static DRIVER_ATTR_WO(remove_id); + +static struct attribute *dax_drv_attrs[] = { + &driver_attr_new_id.attr, + &driver_attr_remove_id.attr, + NULL, +}; +ATTRIBUTE_GROUPS(dax_drv); + +static int dax_bus_match(struct device *dev, struct device_driver *drv); + +/* + * Static dax regions are regions created by an external subsystem + * nvdimm where a single range is assigned. Its boundaries are by the external + * subsystem and are usually limited to one physical memory range. For example, + * for PMEM it is usually defined by NVDIMM Namespace boundaries (i.e. a + * single contiguous range) + * + * On dynamic dax regions, the assigned region can be partitioned by dax core + * into multiple subdivisions. A subdivision is represented into one + * /dev/daxN.M device composed by one or more potentially discontiguous ranges. + * + * When allocating a dax region, drivers must set whether it's static + * (IORESOURCE_DAX_STATIC). On static dax devices, the @pgmap is pre-assigned + * to dax core when calling devm_create_dev_dax(), whereas in dynamic dax + * devices it is NULL but afterwards allocated by dax core on device ->probe(). + * Care is needed to make sure that dynamic dax devices are torn down with a + * cleared @pgmap field (see kill_dev_dax()). + */ +static bool is_static(struct dax_region *dax_region) +{ + return (dax_region->res.flags & IORESOURCE_DAX_STATIC) != 0; +} + +bool static_dev_dax(struct dev_dax *dev_dax) +{ + return is_static(dev_dax->region); +} +EXPORT_SYMBOL_GPL(static_dev_dax); + +static u64 dev_dax_size(struct dev_dax *dev_dax) +{ + u64 size = 0; + int i; + + device_lock_assert(&dev_dax->dev); + + for (i = 0; i < dev_dax->nr_range; i++) + size += range_len(&dev_dax->ranges[i].range); + + return size; +} + +static int dax_bus_probe(struct device *dev) +{ + struct dax_device_driver *dax_drv = to_dax_drv(dev->driver); + struct dev_dax *dev_dax = to_dev_dax(dev); + struct dax_region *dax_region = dev_dax->region; + int rc; + + if (dev_dax_size(dev_dax) == 0 || dev_dax->id < 0) + return -ENXIO; + + rc = dax_drv->probe(dev_dax); + + if (rc || is_static(dax_region)) + return rc; + + /* + * Track new seed creation only after successful probe of the + * previous seed. + */ + if (dax_region->seed == dev) + dax_region->seed = NULL; + + return 0; +} + +static void dax_bus_remove(struct device *dev) +{ + struct dax_device_driver *dax_drv = to_dax_drv(dev->driver); + struct dev_dax *dev_dax = to_dev_dax(dev); + + if (dax_drv->remove) + dax_drv->remove(dev_dax); +} + +static struct bus_type dax_bus_type = { + .name = "dax", + .uevent = dax_bus_uevent, + .match = dax_bus_match, + .probe = dax_bus_probe, + .remove = dax_bus_remove, + .drv_groups = dax_drv_groups, +}; + +static int dax_bus_match(struct device *dev, struct device_driver *drv) +{ + struct dax_device_driver *dax_drv = to_dax_drv(drv); + + if (dax_match_id(dax_drv, dev)) + return 1; + return dax_match_type(dax_drv, dev); +} + +/* + * Rely on the fact that drvdata is set before the attributes are + * registered, and that the attributes are unregistered before drvdata + * is cleared to assume that drvdata is always valid. + */ +static ssize_t id_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct dax_region *dax_region = dev_get_drvdata(dev); + + return sprintf(buf, "%d\n", dax_region->id); +} +static DEVICE_ATTR_RO(id); + +static ssize_t region_size_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct dax_region *dax_region = dev_get_drvdata(dev); + + return sprintf(buf, "%llu\n", (unsigned long long) + resource_size(&dax_region->res)); +} +static struct device_attribute dev_attr_region_size = __ATTR(size, 0444, + region_size_show, NULL); + +static ssize_t region_align_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct dax_region *dax_region = dev_get_drvdata(dev); + + return sprintf(buf, "%u\n", dax_region->align); +} +static struct device_attribute dev_attr_region_align = + __ATTR(align, 0400, region_align_show, NULL); + +#define for_each_dax_region_resource(dax_region, res) \ + for (res = (dax_region)->res.child; res; res = res->sibling) + +static unsigned long long dax_region_avail_size(struct dax_region *dax_region) +{ + resource_size_t size = resource_size(&dax_region->res); + struct resource *res; + + device_lock_assert(dax_region->dev); + + for_each_dax_region_resource(dax_region, res) + size -= resource_size(res); + return size; +} + +static ssize_t available_size_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct dax_region *dax_region = dev_get_drvdata(dev); + unsigned long long size; + + device_lock(dev); + size = dax_region_avail_size(dax_region); + device_unlock(dev); + + return sprintf(buf, "%llu\n", size); +} +static DEVICE_ATTR_RO(available_size); + +static ssize_t seed_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct dax_region *dax_region = dev_get_drvdata(dev); + struct device *seed; + ssize_t rc; + + if (is_static(dax_region)) + return -EINVAL; + + device_lock(dev); + seed = dax_region->seed; + rc = sprintf(buf, "%s\n", seed ? dev_name(seed) : ""); + device_unlock(dev); + + return rc; +} +static DEVICE_ATTR_RO(seed); + +static ssize_t create_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct dax_region *dax_region = dev_get_drvdata(dev); + struct device *youngest; + ssize_t rc; + + if (is_static(dax_region)) + return -EINVAL; + + device_lock(dev); + youngest = dax_region->youngest; + rc = sprintf(buf, "%s\n", youngest ? dev_name(youngest) : ""); + device_unlock(dev); + + return rc; +} + +static ssize_t create_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t len) +{ + struct dax_region *dax_region = dev_get_drvdata(dev); + unsigned long long avail; + ssize_t rc; + int val; + + if (is_static(dax_region)) + return -EINVAL; + + rc = kstrtoint(buf, 0, &val); + if (rc) + return rc; + if (val != 1) + return -EINVAL; + + device_lock(dev); + avail = dax_region_avail_size(dax_region); + if (avail == 0) + rc = -ENOSPC; + else { + struct dev_dax_data data = { + .dax_region = dax_region, + .size = 0, + .id = -1, + }; + struct dev_dax *dev_dax = devm_create_dev_dax(&data); + + if (IS_ERR(dev_dax)) + rc = PTR_ERR(dev_dax); + else { + /* + * In support of crafting multiple new devices + * simultaneously multiple seeds can be created, + * but only the first one that has not been + * successfully bound is tracked as the region + * seed. + */ + if (!dax_region->seed) + dax_region->seed = &dev_dax->dev; + dax_region->youngest = &dev_dax->dev; + rc = len; + } + } + device_unlock(dev); + + return rc; +} +static DEVICE_ATTR_RW(create); + +void kill_dev_dax(struct dev_dax *dev_dax) +{ + struct dax_device *dax_dev = dev_dax->dax_dev; + struct inode *inode = dax_inode(dax_dev); + + kill_dax(dax_dev); + unmap_mapping_range(inode->i_mapping, 0, 0, 1); + + /* + * Dynamic dax region have the pgmap allocated via dev_kzalloc() + * and thus freed by devm. Clear the pgmap to not have stale pgmap + * ranges on probe() from previous reconfigurations of region devices. + */ + if (!static_dev_dax(dev_dax)) + dev_dax->pgmap = NULL; +} +EXPORT_SYMBOL_GPL(kill_dev_dax); + +static void trim_dev_dax_range(struct dev_dax *dev_dax) +{ + int i = dev_dax->nr_range - 1; + struct range *range = &dev_dax->ranges[i].range; + struct dax_region *dax_region = dev_dax->region; + + device_lock_assert(dax_region->dev); + dev_dbg(&dev_dax->dev, "delete range[%d]: %#llx:%#llx\n", i, + (unsigned long long)range->start, + (unsigned long long)range->end); + + __release_region(&dax_region->res, range->start, range_len(range)); + if (--dev_dax->nr_range == 0) { + kfree(dev_dax->ranges); + dev_dax->ranges = NULL; + } +} + +static void free_dev_dax_ranges(struct dev_dax *dev_dax) +{ + while (dev_dax->nr_range) + trim_dev_dax_range(dev_dax); +} + +static void unregister_dev_dax(void *dev) +{ + struct dev_dax *dev_dax = to_dev_dax(dev); + + dev_dbg(dev, "%s\n", __func__); + + kill_dev_dax(dev_dax); + device_del(dev); + free_dev_dax_ranges(dev_dax); + put_device(dev); +} + +static void dax_region_free(struct kref *kref) +{ + struct dax_region *dax_region; + + dax_region = container_of(kref, struct dax_region, kref); + kfree(dax_region); +} + +static void dax_region_put(struct dax_region *dax_region) +{ + kref_put(&dax_region->kref, dax_region_free); +} + +/* a return value >= 0 indicates this invocation invalidated the id */ +static int __free_dev_dax_id(struct dev_dax *dev_dax) +{ + struct device *dev = &dev_dax->dev; + struct dax_region *dax_region; + int rc = dev_dax->id; + + device_lock_assert(dev); + + if (!dev_dax->dyn_id || dev_dax->id < 0) + return -1; + dax_region = dev_dax->region; + ida_free(&dax_region->ida, dev_dax->id); + dax_region_put(dax_region); + dev_dax->id = -1; + return rc; +} + +static int free_dev_dax_id(struct dev_dax *dev_dax) +{ + struct device *dev = &dev_dax->dev; + int rc; + + device_lock(dev); + rc = __free_dev_dax_id(dev_dax); + device_unlock(dev); + return rc; +} + +static int alloc_dev_dax_id(struct dev_dax *dev_dax) +{ + struct dax_region *dax_region = dev_dax->region; + int id; + + id = ida_alloc(&dax_region->ida, GFP_KERNEL); + if (id < 0) + return id; + kref_get(&dax_region->kref); + dev_dax->dyn_id = true; + dev_dax->id = id; + return id; +} + +static ssize_t delete_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t len) +{ + struct dax_region *dax_region = dev_get_drvdata(dev); + struct dev_dax *dev_dax; + struct device *victim; + bool do_del = false; + int rc; + + if (is_static(dax_region)) + return -EINVAL; + + victim = device_find_child_by_name(dax_region->dev, buf); + if (!victim) + return -ENXIO; + + device_lock(dev); + device_lock(victim); + dev_dax = to_dev_dax(victim); + if (victim->driver || dev_dax_size(dev_dax)) + rc = -EBUSY; + else { + /* + * Invalidate the device so it does not become active + * again, but always preserve device-id-0 so that + * /sys/bus/dax/ is guaranteed to be populated while any + * dax_region is registered. + */ + if (dev_dax->id > 0) { + do_del = __free_dev_dax_id(dev_dax) >= 0; + rc = len; + if (dax_region->seed == victim) + dax_region->seed = NULL; + if (dax_region->youngest == victim) + dax_region->youngest = NULL; + } else + rc = -EBUSY; + } + device_unlock(victim); + + /* won the race to invalidate the device, clean it up */ + if (do_del) + devm_release_action(dev, unregister_dev_dax, victim); + device_unlock(dev); + put_device(victim); + + return rc; +} +static DEVICE_ATTR_WO(delete); + +static umode_t dax_region_visible(struct kobject *kobj, struct attribute *a, + int n) +{ + struct device *dev = container_of(kobj, struct device, kobj); + struct dax_region *dax_region = dev_get_drvdata(dev); + + if (is_static(dax_region)) + if (a == &dev_attr_available_size.attr + || a == &dev_attr_create.attr + || a == &dev_attr_seed.attr + || a == &dev_attr_delete.attr) + return 0; + return a->mode; +} + +static struct attribute *dax_region_attributes[] = { + &dev_attr_available_size.attr, + &dev_attr_region_size.attr, + &dev_attr_region_align.attr, + &dev_attr_create.attr, + &dev_attr_seed.attr, + &dev_attr_delete.attr, + &dev_attr_id.attr, + NULL, +}; + +static const struct attribute_group dax_region_attribute_group = { + .name = "dax_region", + .attrs = dax_region_attributes, + .is_visible = dax_region_visible, +}; + +static const struct attribute_group *dax_region_attribute_groups[] = { + &dax_region_attribute_group, + NULL, +}; + +static void dax_region_unregister(void *region) +{ + struct dax_region *dax_region = region; + + sysfs_remove_groups(&dax_region->dev->kobj, + dax_region_attribute_groups); + dax_region_put(dax_region); +} + +struct dax_region *alloc_dax_region(struct device *parent, int region_id, + struct range *range, int target_node, unsigned int align, + unsigned long flags) +{ + struct dax_region *dax_region; + + /* + * The DAX core assumes that it can store its private data in + * parent->driver_data. This WARN is a reminder / safeguard for + * developers of device-dax drivers. + */ + if (dev_get_drvdata(parent)) { + dev_WARN(parent, "dax core failed to setup private data\n"); + return NULL; + } + + if (!IS_ALIGNED(range->start, align) + || !IS_ALIGNED(range_len(range), align)) + return NULL; + + dax_region = kzalloc(sizeof(*dax_region), GFP_KERNEL); + if (!dax_region) + return NULL; + + dev_set_drvdata(parent, dax_region); + kref_init(&dax_region->kref); + dax_region->id = region_id; + dax_region->align = align; + dax_region->dev = parent; + dax_region->target_node = target_node; + ida_init(&dax_region->ida); + dax_region->res = (struct resource) { + .start = range->start, + .end = range->end, + .flags = IORESOURCE_MEM | flags, + }; + + if (sysfs_create_groups(&parent->kobj, dax_region_attribute_groups)) { + kfree(dax_region); + return NULL; + } + + if (devm_add_action_or_reset(parent, dax_region_unregister, dax_region)) + return NULL; + return dax_region; +} +EXPORT_SYMBOL_GPL(alloc_dax_region); + +static void dax_mapping_release(struct device *dev) +{ + struct dax_mapping *mapping = to_dax_mapping(dev); + struct device *parent = dev->parent; + struct dev_dax *dev_dax = to_dev_dax(parent); + + ida_free(&dev_dax->ida, mapping->id); + kfree(mapping); + put_device(parent); +} + +static void unregister_dax_mapping(void *data) +{ + struct device *dev = data; + struct dax_mapping *mapping = to_dax_mapping(dev); + struct dev_dax *dev_dax = to_dev_dax(dev->parent); + struct dax_region *dax_region = dev_dax->region; + + dev_dbg(dev, "%s\n", __func__); + + device_lock_assert(dax_region->dev); + + dev_dax->ranges[mapping->range_id].mapping = NULL; + mapping->range_id = -1; + + device_unregister(dev); +} + +static struct dev_dax_range *get_dax_range(struct device *dev) +{ + struct dax_mapping *mapping = to_dax_mapping(dev); + struct dev_dax *dev_dax = to_dev_dax(dev->parent); + struct dax_region *dax_region = dev_dax->region; + + device_lock(dax_region->dev); + if (mapping->range_id < 0) { + device_unlock(dax_region->dev); + return NULL; + } + + return &dev_dax->ranges[mapping->range_id]; +} + +static void put_dax_range(struct dev_dax_range *dax_range) +{ + struct dax_mapping *mapping = dax_range->mapping; + struct dev_dax *dev_dax = to_dev_dax(mapping->dev.parent); + struct dax_region *dax_region = dev_dax->region; + + device_unlock(dax_region->dev); +} + +static ssize_t start_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct dev_dax_range *dax_range; + ssize_t rc; + + dax_range = get_dax_range(dev); + if (!dax_range) + return -ENXIO; + rc = sprintf(buf, "%#llx\n", dax_range->range.start); + put_dax_range(dax_range); + + return rc; +} +static DEVICE_ATTR(start, 0400, start_show, NULL); + +static ssize_t end_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct dev_dax_range *dax_range; + ssize_t rc; + + dax_range = get_dax_range(dev); + if (!dax_range) + return -ENXIO; + rc = sprintf(buf, "%#llx\n", dax_range->range.end); + put_dax_range(dax_range); + + return rc; +} +static DEVICE_ATTR(end, 0400, end_show, NULL); + +static ssize_t pgoff_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct dev_dax_range *dax_range; + ssize_t rc; + + dax_range = get_dax_range(dev); + if (!dax_range) + return -ENXIO; + rc = sprintf(buf, "%#lx\n", dax_range->pgoff); + put_dax_range(dax_range); + + return rc; +} +static DEVICE_ATTR(page_offset, 0400, pgoff_show, NULL); + +static struct attribute *dax_mapping_attributes[] = { + &dev_attr_start.attr, + &dev_attr_end.attr, + &dev_attr_page_offset.attr, + NULL, +}; + +static const struct attribute_group dax_mapping_attribute_group = { + .attrs = dax_mapping_attributes, +}; + +static const struct attribute_group *dax_mapping_attribute_groups[] = { + &dax_mapping_attribute_group, + NULL, +}; + +static struct device_type dax_mapping_type = { + .release = dax_mapping_release, + .groups = dax_mapping_attribute_groups, +}; + +static int devm_register_dax_mapping(struct dev_dax *dev_dax, int range_id) +{ + struct dax_region *dax_region = dev_dax->region; + struct dax_mapping *mapping; + struct device *dev; + int rc; + + device_lock_assert(dax_region->dev); + + if (dev_WARN_ONCE(&dev_dax->dev, !dax_region->dev->driver, + "region disabled\n")) + return -ENXIO; + + mapping = kzalloc(sizeof(*mapping), GFP_KERNEL); + if (!mapping) + return -ENOMEM; + mapping->range_id = range_id; + mapping->id = ida_alloc(&dev_dax->ida, GFP_KERNEL); + if (mapping->id < 0) { + kfree(mapping); + return -ENOMEM; + } + dev_dax->ranges[range_id].mapping = mapping; + dev = &mapping->dev; + device_initialize(dev); + dev->parent = &dev_dax->dev; + get_device(dev->parent); + dev->type = &dax_mapping_type; + dev_set_name(dev, "mapping%d", mapping->id); + rc = device_add(dev); + if (rc) { + put_device(dev); + return rc; + } + + rc = devm_add_action_or_reset(dax_region->dev, unregister_dax_mapping, + dev); + if (rc) + return rc; + return 0; +} + +static int alloc_dev_dax_range(struct dev_dax *dev_dax, u64 start, + resource_size_t size) +{ + struct dax_region *dax_region = dev_dax->region; + struct resource *res = &dax_region->res; + struct device *dev = &dev_dax->dev; + struct dev_dax_range *ranges; + unsigned long pgoff = 0; + struct resource *alloc; + int i, rc; + + device_lock_assert(dax_region->dev); + + /* handle the seed alloc special case */ + if (!size) { + if (dev_WARN_ONCE(dev, dev_dax->nr_range, + "0-size allocation must be first\n")) + return -EBUSY; + /* nr_range == 0 is elsewhere special cased as 0-size device */ + return 0; + } + + alloc = __request_region(res, start, size, dev_name(dev), 0); + if (!alloc) + return -ENOMEM; + + ranges = krealloc(dev_dax->ranges, sizeof(*ranges) + * (dev_dax->nr_range + 1), GFP_KERNEL); + if (!ranges) { + __release_region(res, alloc->start, resource_size(alloc)); + return -ENOMEM; + } + + for (i = 0; i < dev_dax->nr_range; i++) + pgoff += PHYS_PFN(range_len(&ranges[i].range)); + dev_dax->ranges = ranges; + ranges[dev_dax->nr_range++] = (struct dev_dax_range) { + .pgoff = pgoff, + .range = { + .start = alloc->start, + .end = alloc->end, + }, + }; + + dev_dbg(dev, "alloc range[%d]: %pa:%pa\n", dev_dax->nr_range - 1, + &alloc->start, &alloc->end); + /* + * A dev_dax instance must be registered before mapping device + * children can be added. Defer to devm_create_dev_dax() to add + * the initial mapping device. + */ + if (!device_is_registered(&dev_dax->dev)) + return 0; + + rc = devm_register_dax_mapping(dev_dax, dev_dax->nr_range - 1); + if (rc) + trim_dev_dax_range(dev_dax); + + return rc; +} + +static int adjust_dev_dax_range(struct dev_dax *dev_dax, struct resource *res, resource_size_t size) +{ + int last_range = dev_dax->nr_range - 1; + struct dev_dax_range *dax_range = &dev_dax->ranges[last_range]; + struct dax_region *dax_region = dev_dax->region; + bool is_shrink = resource_size(res) > size; + struct range *range = &dax_range->range; + struct device *dev = &dev_dax->dev; + int rc; + + device_lock_assert(dax_region->dev); + + if (dev_WARN_ONCE(dev, !size, "deletion is handled by dev_dax_shrink\n")) + return -EINVAL; + + rc = adjust_resource(res, range->start, size); + if (rc) + return rc; + + *range = (struct range) { + .start = range->start, + .end = range->start + size - 1, + }; + + dev_dbg(dev, "%s range[%d]: %#llx:%#llx\n", is_shrink ? "shrink" : "extend", + last_range, (unsigned long long) range->start, + (unsigned long long) range->end); + + return 0; +} + +static ssize_t size_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct dev_dax *dev_dax = to_dev_dax(dev); + unsigned long long size; + + device_lock(dev); + size = dev_dax_size(dev_dax); + device_unlock(dev); + + return sprintf(buf, "%llu\n", size); +} + +static bool alloc_is_aligned(struct dev_dax *dev_dax, resource_size_t size) +{ + /* + * The minimum mapping granularity for a device instance is a + * single subsection, unless the arch says otherwise. + */ + return IS_ALIGNED(size, max_t(unsigned long, dev_dax->align, memremap_compat_align())); +} + +static int dev_dax_shrink(struct dev_dax *dev_dax, resource_size_t size) +{ + resource_size_t to_shrink = dev_dax_size(dev_dax) - size; + struct dax_region *dax_region = dev_dax->region; + struct device *dev = &dev_dax->dev; + int i; + + for (i = dev_dax->nr_range - 1; i >= 0; i--) { + struct range *range = &dev_dax->ranges[i].range; + struct dax_mapping *mapping = dev_dax->ranges[i].mapping; + struct resource *adjust = NULL, *res; + resource_size_t shrink; + + shrink = min_t(u64, to_shrink, range_len(range)); + if (shrink >= range_len(range)) { + devm_release_action(dax_region->dev, + unregister_dax_mapping, &mapping->dev); + trim_dev_dax_range(dev_dax); + to_shrink -= shrink; + if (!to_shrink) + break; + continue; + } + + for_each_dax_region_resource(dax_region, res) + if (strcmp(res->name, dev_name(dev)) == 0 + && res->start == range->start) { + adjust = res; + break; + } + + if (dev_WARN_ONCE(dev, !adjust || i != dev_dax->nr_range - 1, + "failed to find matching resource\n")) + return -ENXIO; + return adjust_dev_dax_range(dev_dax, adjust, range_len(range) + - shrink); + } + return 0; +} + +/* + * Only allow adjustments that preserve the relative pgoff of existing + * allocations. I.e. the dev_dax->ranges array is ordered by increasing pgoff. + */ +static bool adjust_ok(struct dev_dax *dev_dax, struct resource *res) +{ + struct dev_dax_range *last; + int i; + + if (dev_dax->nr_range == 0) + return false; + if (strcmp(res->name, dev_name(&dev_dax->dev)) != 0) + return false; + last = &dev_dax->ranges[dev_dax->nr_range - 1]; + if (last->range.start != res->start || last->range.end != res->end) + return false; + for (i = 0; i < dev_dax->nr_range - 1; i++) { + struct dev_dax_range *dax_range = &dev_dax->ranges[i]; + + if (dax_range->pgoff > last->pgoff) + return false; + } + + return true; +} + +static ssize_t dev_dax_resize(struct dax_region *dax_region, + struct dev_dax *dev_dax, resource_size_t size) +{ + resource_size_t avail = dax_region_avail_size(dax_region), to_alloc; + resource_size_t dev_size = dev_dax_size(dev_dax); + struct resource *region_res = &dax_region->res; + struct device *dev = &dev_dax->dev; + struct resource *res, *first; + resource_size_t alloc = 0; + int rc; + + if (dev->driver) + return -EBUSY; + if (size == dev_size) + return 0; + if (size > dev_size && size - dev_size > avail) + return -ENOSPC; + if (size < dev_size) + return dev_dax_shrink(dev_dax, size); + + to_alloc = size - dev_size; + if (dev_WARN_ONCE(dev, !alloc_is_aligned(dev_dax, to_alloc), + "resize of %pa misaligned\n", &to_alloc)) + return -ENXIO; + + /* + * Expand the device into the unused portion of the region. This + * may involve adjusting the end of an existing resource, or + * allocating a new resource. + */ +retry: + first = region_res->child; + if (!first) + return alloc_dev_dax_range(dev_dax, dax_region->res.start, to_alloc); + + rc = -ENOSPC; + for (res = first; res; res = res->sibling) { + struct resource *next = res->sibling; + + /* space at the beginning of the region */ + if (res == first && res->start > dax_region->res.start) { + alloc = min(res->start - dax_region->res.start, to_alloc); + rc = alloc_dev_dax_range(dev_dax, dax_region->res.start, alloc); + break; + } + + alloc = 0; + /* space between allocations */ + if (next && next->start > res->end + 1) + alloc = min(next->start - (res->end + 1), to_alloc); + + /* space at the end of the region */ + if (!alloc && !next && res->end < region_res->end) + alloc = min(region_res->end - res->end, to_alloc); + + if (!alloc) + continue; + + if (adjust_ok(dev_dax, res)) { + rc = adjust_dev_dax_range(dev_dax, res, resource_size(res) + alloc); + break; + } + rc = alloc_dev_dax_range(dev_dax, res->end + 1, alloc); + break; + } + if (rc) + return rc; + to_alloc -= alloc; + if (to_alloc) + goto retry; + return 0; +} + +static ssize_t size_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t len) +{ + ssize_t rc; + unsigned long long val; + struct dev_dax *dev_dax = to_dev_dax(dev); + struct dax_region *dax_region = dev_dax->region; + + rc = kstrtoull(buf, 0, &val); + if (rc) + return rc; + + if (!alloc_is_aligned(dev_dax, val)) { + dev_dbg(dev, "%s: size: %lld misaligned\n", __func__, val); + return -EINVAL; + } + + device_lock(dax_region->dev); + if (!dax_region->dev->driver) { + device_unlock(dax_region->dev); + return -ENXIO; + } + device_lock(dev); + rc = dev_dax_resize(dax_region, dev_dax, val); + device_unlock(dev); + device_unlock(dax_region->dev); + + return rc == 0 ? len : rc; +} +static DEVICE_ATTR_RW(size); + +static ssize_t range_parse(const char *opt, size_t len, struct range *range) +{ + unsigned long long addr = 0; + char *start, *end, *str; + ssize_t rc = -EINVAL; + + str = kstrdup(opt, GFP_KERNEL); + if (!str) + return rc; + + end = str; + start = strsep(&end, "-"); + if (!start || !end) + goto err; + + rc = kstrtoull(start, 16, &addr); + if (rc) + goto err; + range->start = addr; + + rc = kstrtoull(end, 16, &addr); + if (rc) + goto err; + range->end = addr; + +err: + kfree(str); + return rc; +} + +static ssize_t mapping_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t len) +{ + struct dev_dax *dev_dax = to_dev_dax(dev); + struct dax_region *dax_region = dev_dax->region; + size_t to_alloc; + struct range r; + ssize_t rc; + + rc = range_parse(buf, len, &r); + if (rc) + return rc; + + rc = -ENXIO; + device_lock(dax_region->dev); + if (!dax_region->dev->driver) { + device_unlock(dax_region->dev); + return rc; + } + device_lock(dev); + + to_alloc = range_len(&r); + if (alloc_is_aligned(dev_dax, to_alloc)) + rc = alloc_dev_dax_range(dev_dax, r.start, to_alloc); + device_unlock(dev); + device_unlock(dax_region->dev); + + return rc == 0 ? len : rc; +} +static DEVICE_ATTR_WO(mapping); + +static ssize_t align_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct dev_dax *dev_dax = to_dev_dax(dev); + + return sprintf(buf, "%d\n", dev_dax->align); +} + +static ssize_t dev_dax_validate_align(struct dev_dax *dev_dax) +{ + struct device *dev = &dev_dax->dev; + int i; + + for (i = 0; i < dev_dax->nr_range; i++) { + size_t len = range_len(&dev_dax->ranges[i].range); + + if (!alloc_is_aligned(dev_dax, len)) { + dev_dbg(dev, "%s: align %u invalid for range %d\n", + __func__, dev_dax->align, i); + return -EINVAL; + } + } + + return 0; +} + +static ssize_t align_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t len) +{ + struct dev_dax *dev_dax = to_dev_dax(dev); + struct dax_region *dax_region = dev_dax->region; + unsigned long val, align_save; + ssize_t rc; + + rc = kstrtoul(buf, 0, &val); + if (rc) + return -ENXIO; + + if (!dax_align_valid(val)) + return -EINVAL; + + device_lock(dax_region->dev); + if (!dax_region->dev->driver) { + device_unlock(dax_region->dev); + return -ENXIO; + } + + device_lock(dev); + if (dev->driver) { + rc = -EBUSY; + goto out_unlock; + } + + align_save = dev_dax->align; + dev_dax->align = val; + rc = dev_dax_validate_align(dev_dax); + if (rc) + dev_dax->align = align_save; +out_unlock: + device_unlock(dev); + device_unlock(dax_region->dev); + return rc == 0 ? len : rc; +} +static DEVICE_ATTR_RW(align); + +static int dev_dax_target_node(struct dev_dax *dev_dax) +{ + struct dax_region *dax_region = dev_dax->region; + + return dax_region->target_node; +} + +static ssize_t target_node_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct dev_dax *dev_dax = to_dev_dax(dev); + + return sprintf(buf, "%d\n", dev_dax_target_node(dev_dax)); +} +static DEVICE_ATTR_RO(target_node); + +static ssize_t resource_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct dev_dax *dev_dax = to_dev_dax(dev); + struct dax_region *dax_region = dev_dax->region; + unsigned long long start; + + if (dev_dax->nr_range < 1) + start = dax_region->res.start; + else + start = dev_dax->ranges[0].range.start; + + return sprintf(buf, "%#llx\n", start); +} +static DEVICE_ATTR(resource, 0400, resource_show, NULL); + +static ssize_t modalias_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + /* + * We only ever expect to handle device-dax instances, i.e. the + * @type argument to MODULE_ALIAS_DAX_DEVICE() is always zero + */ + return sprintf(buf, DAX_DEVICE_MODALIAS_FMT "\n", 0); +} +static DEVICE_ATTR_RO(modalias); + +static ssize_t numa_node_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sprintf(buf, "%d\n", dev_to_node(dev)); +} +static DEVICE_ATTR_RO(numa_node); + +static umode_t dev_dax_visible(struct kobject *kobj, struct attribute *a, int n) +{ + struct device *dev = container_of(kobj, struct device, kobj); + struct dev_dax *dev_dax = to_dev_dax(dev); + struct dax_region *dax_region = dev_dax->region; + + if (a == &dev_attr_target_node.attr && dev_dax_target_node(dev_dax) < 0) + return 0; + if (a == &dev_attr_numa_node.attr && !IS_ENABLED(CONFIG_NUMA)) + return 0; + if (a == &dev_attr_mapping.attr && is_static(dax_region)) + return 0; + if ((a == &dev_attr_align.attr || + a == &dev_attr_size.attr) && is_static(dax_region)) + return 0444; + return a->mode; +} + +static struct attribute *dev_dax_attributes[] = { + &dev_attr_modalias.attr, + &dev_attr_size.attr, + &dev_attr_mapping.attr, + &dev_attr_target_node.attr, + &dev_attr_align.attr, + &dev_attr_resource.attr, + &dev_attr_numa_node.attr, + NULL, +}; + +static const struct attribute_group dev_dax_attribute_group = { + .attrs = dev_dax_attributes, + .is_visible = dev_dax_visible, +}; + +static const struct attribute_group *dax_attribute_groups[] = { + &dev_dax_attribute_group, + NULL, +}; + +static void dev_dax_release(struct device *dev) +{ + struct dev_dax *dev_dax = to_dev_dax(dev); + struct dax_device *dax_dev = dev_dax->dax_dev; + + put_dax(dax_dev); + free_dev_dax_id(dev_dax); + kfree(dev_dax->pgmap); + kfree(dev_dax); +} + +static const struct device_type dev_dax_type = { + .release = dev_dax_release, + .groups = dax_attribute_groups, +}; + +struct dev_dax *devm_create_dev_dax(struct dev_dax_data *data) +{ + struct dax_region *dax_region = data->dax_region; + struct device *parent = dax_region->dev; + struct dax_device *dax_dev; + struct dev_dax *dev_dax; + struct inode *inode; + struct device *dev; + int rc; + + dev_dax = kzalloc(sizeof(*dev_dax), GFP_KERNEL); + if (!dev_dax) + return ERR_PTR(-ENOMEM); + + dev_dax->region = dax_region; + if (is_static(dax_region)) { + if (dev_WARN_ONCE(parent, data->id < 0, + "dynamic id specified to static region\n")) { + rc = -EINVAL; + goto err_id; + } + + dev_dax->id = data->id; + } else { + if (dev_WARN_ONCE(parent, data->id >= 0, + "static id specified to dynamic region\n")) { + rc = -EINVAL; + goto err_id; + } + + rc = alloc_dev_dax_id(dev_dax); + if (rc < 0) + goto err_id; + } + + dev = &dev_dax->dev; + device_initialize(dev); + dev_set_name(dev, "dax%d.%d", dax_region->id, dev_dax->id); + + rc = alloc_dev_dax_range(dev_dax, dax_region->res.start, data->size); + if (rc) + goto err_range; + + if (data->pgmap) { + dev_WARN_ONCE(parent, !is_static(dax_region), + "custom dev_pagemap requires a static dax_region\n"); + + dev_dax->pgmap = kmemdup(data->pgmap, + sizeof(struct dev_pagemap), GFP_KERNEL); + if (!dev_dax->pgmap) { + rc = -ENOMEM; + goto err_pgmap; + } + } + + /* + * No dax_operations since there is no access to this device outside of + * mmap of the resulting character device. + */ + dax_dev = alloc_dax(dev_dax, NULL); + if (IS_ERR(dax_dev)) { + rc = PTR_ERR(dax_dev); + goto err_alloc_dax; + } + set_dax_synchronous(dax_dev); + set_dax_nocache(dax_dev); + set_dax_nomc(dax_dev); + + /* a device_dax instance is dead while the driver is not attached */ + kill_dax(dax_dev); + + dev_dax->dax_dev = dax_dev; + dev_dax->target_node = dax_region->target_node; + dev_dax->align = dax_region->align; + ida_init(&dev_dax->ida); + + inode = dax_inode(dax_dev); + dev->devt = inode->i_rdev; + dev->bus = &dax_bus_type; + dev->parent = parent; + dev->type = &dev_dax_type; + + rc = device_add(dev); + if (rc) { + kill_dev_dax(dev_dax); + put_device(dev); + return ERR_PTR(rc); + } + + rc = devm_add_action_or_reset(dax_region->dev, unregister_dev_dax, dev); + if (rc) + return ERR_PTR(rc); + + /* register mapping device for the initial allocation range */ + if (dev_dax->nr_range && range_len(&dev_dax->ranges[0].range)) { + rc = devm_register_dax_mapping(dev_dax, 0); + if (rc) + return ERR_PTR(rc); + } + + return dev_dax; + +err_alloc_dax: + kfree(dev_dax->pgmap); +err_pgmap: + free_dev_dax_ranges(dev_dax); +err_range: + free_dev_dax_id(dev_dax); +err_id: + kfree(dev_dax); + + return ERR_PTR(rc); +} +EXPORT_SYMBOL_GPL(devm_create_dev_dax); + +int __dax_driver_register(struct dax_device_driver *dax_drv, + struct module *module, const char *mod_name) +{ + struct device_driver *drv = &dax_drv->drv; + + /* + * dax_bus_probe() calls dax_drv->probe() unconditionally. + * So better be safe than sorry and ensure it is provided. + */ + if (!dax_drv->probe) + return -EINVAL; + + INIT_LIST_HEAD(&dax_drv->ids); + drv->owner = module; + drv->name = mod_name; + drv->mod_name = mod_name; + drv->bus = &dax_bus_type; + + return driver_register(drv); +} +EXPORT_SYMBOL_GPL(__dax_driver_register); + +void dax_driver_unregister(struct dax_device_driver *dax_drv) +{ + struct device_driver *drv = &dax_drv->drv; + struct dax_id *dax_id, *_id; + + mutex_lock(&dax_bus_lock); + list_for_each_entry_safe(dax_id, _id, &dax_drv->ids, list) { + list_del(&dax_id->list); + kfree(dax_id); + } + mutex_unlock(&dax_bus_lock); + driver_unregister(drv); +} +EXPORT_SYMBOL_GPL(dax_driver_unregister); + +int __init dax_bus_init(void) +{ + return bus_register(&dax_bus_type); +} + +void __exit dax_bus_exit(void) +{ + bus_unregister(&dax_bus_type); +} |