// 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);
/*
* All changes to the dax region configuration occur with this lock held
* for write.
*/
DECLARE_RWSEM(dax_region_rwsem);
/*
* All changes to the dax device configuration occur with this lock held
* for write.
*/
DECLARE_RWSEM(dax_dev_rwsem);
#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);
}
#define to_dax_drv(__drv) container_of_const(__drv, struct dax_device_driver, drv)
static struct dax_id *__dax_match_id(const 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(const 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(const 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) {
strscpy(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, const 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;
lockdep_assert_held(&dax_dev_rwsem);
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;
u64 size;
rc = down_read_interruptible(&dax_dev_rwsem);
if (rc)
return rc;
size = dev_dax_size(dev_dax);
up_read(&dax_dev_rwsem);
if (size == 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 const 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, const struct device_driver *drv)
{
const 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 sysfs_emit(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 sysfs_emit(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 sysfs_emit(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;
lockdep_assert_held(&dax_region_rwsem);
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;
int rc;
rc = down_read_interruptible(&dax_region_rwsem);
if (rc)
return rc;
size = dax_region_avail_size(dax_region);
up_read(&dax_region_rwsem);
return sysfs_emit(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;
rc = down_read_interruptible(&dax_region_rwsem);
if (rc)
return rc;
seed = dax_region->seed;
rc = sysfs_emit(buf, "%s\n", seed ? dev_name(seed) : "");
up_read(&dax_region_rwsem);
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;
rc = down_read_interruptible(&dax_region_rwsem);
if (rc)
return rc;
youngest = dax_region->youngest;
rc = sysfs_emit(buf, "%s\n", youngest ? dev_name(youngest) : "");
up_read(&dax_region_rwsem);
return rc;
}
static struct dev_dax *__devm_create_dev_dax(struct dev_dax_data *data);
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;
rc = down_write_killable(&dax_region_rwsem);
if (rc)
return rc;
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,
.memmap_on_memory = false,
};
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;
}
}
up_write(&dax_region_rwsem);
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;
lockdep_assert_held_write(&dax_region_rwsem);
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__);
down_write(&dax_region_rwsem);
kill_dev_dax(dev_dax);
device_del(dev);
free_dev_dax_ranges(dev_dax);
put_device(dev);
up_write(&dax_region_rwsem);
}
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 dax_region *dax_region;
int rc = dev_dax->id;
lockdep_assert_held_write(&dax_dev_rwsem);
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)
{
int rc;
rc = down_write_killable(&dax_dev_rwsem);
if (rc)
return rc;
rc = __free_dev_dax_id(dev_dax);
up_write(&dax_dev_rwsem);
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);
down_write(&dax_dev_rwsem);
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;
}
up_write(&dax_dev_rwsem);
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);
dev_dbg(dev, "%s\n", __func__);
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);
int rc;
rc = down_write_killable(&dax_region_rwsem);
if (rc)
return NULL;
if (mapping->range_id < 0) {
up_write(&dax_region_rwsem);
return NULL;
}
return &dev_dax->ranges[mapping->range_id];
}
static void put_dax_range(void)
{
up_write(&dax_region_rwsem);
}
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 = sysfs_emit(buf, "%#llx\n", dax_range->range.start);
put_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 = sysfs_emit(buf, "%#llx\n", dax_range->range.end);
put_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 = sysfs_emit(buf, "%#lx\n", dax_range->pgoff);
put_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 const 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;
lockdep_assert_held_write(&dax_region_rwsem);
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;
lockdep_assert_held_write(&dax_region_rwsem);
/* 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];
bool is_shrink = resource_size(res) > size;
struct range *range = &dax_range->range;
struct device *dev = &dev_dax->dev;
int rc;
lockdep_assert_held_write(&dax_region_rwsem);
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;
int rc;
rc = down_read_interruptible(&dax_dev_rwsem);
if (rc)
return rc;
size = dev_dax_size(dev_dax);
up_read(&dax_dev_rwsem);
return sysfs_emit(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;
}
rc = down_write_killable(&dax_region_rwsem);
if (rc)
return rc;
if (!dax_region->dev->driver) {
rc = -ENXIO;
goto err_region;
}
rc = down_write_killable(&dax_dev_rwsem);
if (rc)
goto err_dev;
rc = dev_dax_resize(dax_region, dev_dax, val);
err_dev:
up_write(&dax_dev_rwsem);
err_region:
up_write(&dax_region_rwsem);
if (rc == 0)
return len;
return 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 = down_write_killable(&dax_region_rwsem);
if (rc)
return rc;
if (!dax_region->dev->driver) {
up_write(&dax_region_rwsem);
return rc;
}
rc = down_write_killable(&dax_dev_rwsem);
if (rc) {
up_write(&dax_region_rwsem);
return rc;
}
to_alloc = range_len(&r);
if (alloc_is_aligned(dev_dax, to_alloc))
rc = alloc_dev_dax_range(dev_dax, r.start, to_alloc);
up_write(&dax_dev_rwsem);
up_write(&dax_region_rwsem);
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 sysfs_emit(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;
rc = down_write_killable(&dax_region_rwsem);
if (rc)
return rc;
if (!dax_region->dev->driver) {
up_write(&dax_region_rwsem);
return -ENXIO;
}
rc = down_write_killable(&dax_dev_rwsem);
if (rc) {
up_write(&dax_region_rwsem);
return rc;
}
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:
up_write(&dax_dev_rwsem);
up_write(&dax_region_rwsem);
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 sysfs_emit(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 sysfs_emit(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 sysfs_emit(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 sysfs_emit(buf, "%d\n", dev_to_node(dev));
}
static DEVICE_ATTR_RO(numa_node);
static ssize_t memmap_on_memory_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct dev_dax *dev_dax = to_dev_dax(dev);
return sysfs_emit(buf, "%d\n", dev_dax->memmap_on_memory);
}
static ssize_t memmap_on_memory_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t len)
{
struct dev_dax *dev_dax = to_dev_dax(dev);
bool val;
int rc;
rc = kstrtobool(buf, &val);
if (rc)
return rc;
if (val == true && !mhp_supports_memmap_on_memory()) {
dev_dbg(dev, "memmap_on_memory is not available\n");
return -EOPNOTSUPP;
}
rc = down_write_killable(&dax_dev_rwsem);
if (rc)
return rc;
if (dev_dax->memmap_on_memory != val && dev->driver &&
to_dax_drv(dev->driver)->type == DAXDRV_KMEM_TYPE) {
up_write(&dax_dev_rwsem);
return -EBUSY;
}
dev_dax->memmap_on_memory = val;
up_write(&dax_dev_rwsem);
return len;
}
static DEVICE_ATTR_RW(memmap_on_memory);
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,
&dev_attr_memmap_on_memory.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,
};
static 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);
dev_dax->memmap_on_memory = data->memmap_on_memory;
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);
}
struct dev_dax *devm_create_dev_dax(struct dev_dax_data *data)
{
struct dev_dax *dev_dax;
down_write(&dax_region_rwsem);
dev_dax = __devm_create_dev_dax(data);
up_write(&dax_region_rwsem);
return dev_dax;
}
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);
}
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