Merge tag 'usb-5.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb
[linux-2.6-microblaze.git] / drivers / dax / bus.c
index df238c8..27513d3 100644 (file)
@@ -6,6 +6,7 @@
 #include <linux/list.h>
 #include <linux/slab.h>
 #include <linux/dax.h>
+#include <linux/io.h>
 #include "dax-private.h"
 #include "bus.h"
 
@@ -130,10 +131,63 @@ ATTRIBUTE_GROUPS(dax_drv);
 
 static int dax_bus_match(struct device *dev, struct device_driver *drv);
 
+static bool is_static(struct dax_region *dax_region)
+{
+       return (dax_region->res.flags & IORESOURCE_DAX_STATIC) != 0;
+}
+
+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 int 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);
+
+       return 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,
 };
 
@@ -176,18 +230,269 @@ static ssize_t region_size_show(struct device *dev,
 static struct device_attribute dev_attr_region_size = __ATTR(size, 0444,
                region_size_show, NULL);
 
-static ssize_t align_show(struct device *dev,
+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 DEVICE_ATTR_RO(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);
+}
+EXPORT_SYMBOL_GPL(kill_dev_dax);
+
+static void free_dev_dax_ranges(struct dev_dax *dev_dax)
+{
+       struct dax_region *dax_region = dev_dax->region;
+       int i;
+
+       device_lock_assert(dax_region->dev);
+       for (i = 0; i < dev_dax->nr_range; i++) {
+               struct range *range = &dev_dax->ranges[i].range;
+
+               __release_region(&dax_region->res, range->start,
+                               range_len(range));
+       }
+       dev_dax->nr_range = 0;
+}
+
+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);
+       free_dev_dax_ranges(dev_dax);
+       device_del(dev);
+       put_device(dev);
+}
+
+/* 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 = dev_dax->region;
+       struct device *dev = &dev_dax->dev;
+       int rc = dev_dax->id;
+
+       device_lock_assert(dev);
+
+       if (is_static(dax_region) || dev_dax->id < 0)
+               return -1;
+       ida_free(&dax_region->ida, dev_dax->id);
+       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 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_align.attr,
+       &dev_attr_region_align.attr,
+       &dev_attr_create.attr,
+       &dev_attr_seed.attr,
+       &dev_attr_delete.attr,
        &dev_attr_id.attr,
        NULL,
 };
@@ -195,6 +500,7 @@ static struct attribute *dax_region_attributes[] = {
 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[] = {
@@ -226,8 +532,8 @@ static void dax_region_unregister(void *region)
 }
 
 struct dax_region *alloc_dax_region(struct device *parent, int region_id,
-               struct resource *res, int target_node, unsigned int align,
-               unsigned long long pfn_flags)
+               struct range *range, int target_node, unsigned int align,
+               unsigned long flags)
 {
        struct dax_region *dax_region;
 
@@ -241,8 +547,8 @@ struct dax_region *alloc_dax_region(struct device *parent, int region_id,
                return NULL;
        }
 
-       if (!IS_ALIGNED(res->start, align)
-                       || !IS_ALIGNED(resource_size(res), align))
+       if (!IS_ALIGNED(range->start, align)
+                       || !IS_ALIGNED(range_len(range), align))
                return NULL;
 
        dax_region = kzalloc(sizeof(*dax_region), GFP_KERNEL);
@@ -250,13 +556,18 @@ struct dax_region *alloc_dax_region(struct device *parent, int region_id,
                return NULL;
 
        dev_set_drvdata(parent, dax_region);
-       memcpy(&dax_region->res, res, sizeof(*res));
-       dax_region->pfn_flags = pfn_flags;
        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;
@@ -269,45 +580,631 @@ struct dax_region *alloc_dax_region(struct device *parent, int region_id,
 }
 EXPORT_SYMBOL_GPL(alloc_dax_region);
 
+static void dax_mapping_release(struct device *dev)
+{
+       struct dax_mapping *mapping = to_dax_mapping(dev);
+       struct dev_dax *dev_dax = to_dev_dax(dev->parent);
+
+       ida_free(&dev_dax->ida, mapping->id);
+       kfree(mapping);
+}
+
+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_del(dev);
+       put_device(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;
+       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;
+       }
+
+       ranges = krealloc(dev_dax->ranges, sizeof(*ranges)
+                       * (dev_dax->nr_range + 1), GFP_KERNEL);
+       if (!ranges)
+               return -ENOMEM;
+
+       alloc = __request_region(res, start, size, dev_name(dev), 0);
+       if (!alloc) {
+               /*
+                * If this was an empty set of ranges nothing else
+                * will release @ranges, so do it now.
+                */
+               if (!dev_dax->nr_range) {
+                       kfree(ranges);
+                       ranges = NULL;
+               }
+               dev_dax->ranges = ranges;
+               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) {
+               dev_dbg(dev, "delete range[%d]: %pa:%pa\n", dev_dax->nr_range - 1,
+                               &alloc->start, &alloc->end);
+               dev_dax->nr_range--;
+               __release_region(res, alloc->start, resource_size(alloc));
+               return rc;
+       }
+
+       return 0;
+}
+
+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 = resource_size(&dev_dax->region->res);
+       unsigned long long size;
+
+       device_lock(dev);
+       size = dev_dax_size(dev_dax);
+       device_unlock(dev);
 
        return sprintf(buf, "%llu\n", size);
 }
-static DEVICE_ATTR_RO(size);
 
-static int dev_dax_target_node(struct dev_dax *dev_dax)
+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);
+                       __release_region(&dax_region->res, range->start,
+                                       range_len(range));
+                       dev_dax->nr_range--;
+                       dev_dbg(dev, "delete range[%d]: %#llx:%#llx\n", i,
+                                       (unsigned long long) range->start,
+                                       (unsigned long long) range->end);
+                       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;
+}
 
-       return dax_region->target_node;
+/*
+ * 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 target_node_show(struct device *dev,
+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_target_node(dev_dax));
+       return sprintf(buf, "%d\n", dev_dax->align);
 }
-static DEVICE_ATTR_RO(target_node);
 
-static unsigned long long dev_dax_resource(struct dev_dax *dev_dax)
+static ssize_t dev_dax_validate_align(struct dev_dax *dev_dax)
 {
+       resource_size_t dev_size = dev_dax_size(dev_dax);
+       struct device *dev = &dev_dax->dev;
+       int i;
+
+       if (dev_size > 0 && !alloc_is_aligned(dev_dax, dev_size)) {
+               dev_dbg(dev, "%s: align %u invalid for size %pa\n",
+                       __func__, dev_dax->align, &dev_size);
+               return -EINVAL;
+       }
+
+       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;
 
-       return dax_region->res.start;
+       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", dev_dax_resource(dev_dax));
+       return sprintf(buf, "%#llx\n", start);
 }
 static DEVICE_ATTR(resource, 0400, resource_show, NULL);
 
@@ -333,18 +1230,26 @@ 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,
@@ -360,24 +1265,17 @@ static const struct attribute_group *dax_attribute_groups[] = {
        NULL,
 };
 
-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);
-}
-EXPORT_SYMBOL_GPL(kill_dev_dax);
-
 static void dev_dax_release(struct device *dev)
 {
        struct dev_dax *dev_dax = to_dev_dax(dev);
        struct dax_region *dax_region = dev_dax->region;
        struct dax_device *dax_dev = dev_dax->dax_dev;
 
-       dax_region_put(dax_region);
        put_dax(dax_dev);
+       free_dev_dax_id(dev_dax);
+       dax_region_put(dax_region);
+       kfree(dev_dax->ranges);
+       kfree(dev_dax->pgmap);
        kfree(dev_dax);
 }
 
@@ -386,35 +1284,61 @@ static const struct device_type dev_dax_type = {
        .groups = dax_attribute_groups,
 };
 
-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);
-       put_device(dev);
-}
-
-struct dev_dax *__devm_create_dev_dax(struct dax_region *dax_region, int id,
-               struct dev_pagemap *pgmap, enum dev_dax_subsys subsys)
+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 = -ENOMEM;
-
-       if (id < 0)
-               return ERR_PTR(-EINVAL);
+       int rc;
 
        dev_dax = kzalloc(sizeof(*dev_dax), GFP_KERNEL);
        if (!dev_dax)
                return ERR_PTR(-ENOMEM);
 
-       memcpy(&dev_dax->pgmap, pgmap, sizeof(*pgmap));
+       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 = ida_alloc(&dax_region->ida, GFP_KERNEL);
+               if (rc < 0)
+                       goto err_id;
+               dev_dax->id = rc;
+       }
+
+       dev_dax->region = dax_region;
+       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 'host' or dax_operations since there is no access to this
@@ -423,30 +1347,26 @@ struct dev_dax *__devm_create_dev_dax(struct dax_region *dax_region, int id,
        dax_dev = alloc_dax(dev_dax, NULL, NULL, DAXDEV_F_SYNC);
        if (IS_ERR(dax_dev)) {
                rc = PTR_ERR(dax_dev);
-               goto err;
+               goto err_alloc_dax;
        }
 
        /* a device_dax instance is dead while the driver is not attached */
        kill_dax(dax_dev);
 
-       /* from here on we're committed to teardown via dax_dev_release() */
-       dev = &dev_dax->dev;
-       device_initialize(dev);
-
        dev_dax->dax_dev = dax_dev;
-       dev_dax->region = dax_region;
        dev_dax->target_node = dax_region->target_node;
+       dev_dax->align = dax_region->align;
+       ida_init(&dev_dax->ida);
        kref_get(&dax_region->kref);
 
        inode = dax_inode(dax_dev);
        dev->devt = inode->i_rdev;
-       if (subsys == DEV_DAX_BUS)
+       if (data->subsys == DEV_DAX_BUS)
                dev->bus = &dax_bus_type;
        else
                dev->class = dax_class;
        dev->parent = parent;
        dev->type = &dev_dax_type;
-       dev_set_name(dev, "dax%d.%d", dax_region->id, id);
 
        rc = device_add(dev);
        if (rc) {
@@ -459,14 +1379,27 @@ struct dev_dax *__devm_create_dev_dax(struct dax_region *dax_region, int id,
        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:
+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);
+EXPORT_SYMBOL_GPL(devm_create_dev_dax);
 
 static int match_always_count;