1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright(c) 2017-2018 Intel Corporation. All rights reserved. */
3 #include <linux/memremap.h>
4 #include <linux/device.h>
5 #include <linux/mutex.h>
6 #include <linux/list.h>
7 #include <linux/slab.h>
10 #include "dax-private.h"
13 static DEFINE_MUTEX(dax_bus_lock);
16 * All changes to the dax region configuration occur with this lock held
19 DECLARE_RWSEM(dax_region_rwsem);
22 * All changes to the dax device configuration occur with this lock held
25 DECLARE_RWSEM(dax_dev_rwsem);
27 #define DAX_NAME_LEN 30
29 struct list_head list;
30 char dev_name[DAX_NAME_LEN];
33 static int dax_bus_uevent(const struct device *dev, struct kobj_uevent_env *env)
36 * We only ever expect to handle device-dax instances, i.e. the
37 * @type argument to MODULE_ALIAS_DAX_DEVICE() is always zero
39 return add_uevent_var(env, "MODALIAS=" DAX_DEVICE_MODALIAS_FMT, 0);
42 static struct dax_device_driver *to_dax_drv(struct device_driver *drv)
44 return container_of(drv, struct dax_device_driver, drv);
47 static struct dax_id *__dax_match_id(struct dax_device_driver *dax_drv,
50 struct dax_id *dax_id;
52 lockdep_assert_held(&dax_bus_lock);
54 list_for_each_entry(dax_id, &dax_drv->ids, list)
55 if (sysfs_streq(dax_id->dev_name, dev_name))
60 static int dax_match_id(struct dax_device_driver *dax_drv, struct device *dev)
64 mutex_lock(&dax_bus_lock);
65 match = !!__dax_match_id(dax_drv, dev_name(dev));
66 mutex_unlock(&dax_bus_lock);
71 static int dax_match_type(struct dax_device_driver *dax_drv, struct device *dev)
73 enum dax_driver_type type = DAXDRV_DEVICE_TYPE;
74 struct dev_dax *dev_dax = to_dev_dax(dev);
76 if (dev_dax->region->res.flags & IORESOURCE_DAX_KMEM)
77 type = DAXDRV_KMEM_TYPE;
79 if (dax_drv->type == type)
82 /* default to device mode if dax_kmem is disabled */
83 if (dax_drv->type == DAXDRV_DEVICE_TYPE &&
84 !IS_ENABLED(CONFIG_DEV_DAX_KMEM))
95 static ssize_t do_id_store(struct device_driver *drv, const char *buf,
96 size_t count, enum id_action action)
98 struct dax_device_driver *dax_drv = to_dax_drv(drv);
99 unsigned int region_id, id;
100 char devname[DAX_NAME_LEN];
101 struct dax_id *dax_id;
105 fields = sscanf(buf, "dax%d.%d", ®ion_id, &id);
108 sprintf(devname, "dax%d.%d", region_id, id);
109 if (!sysfs_streq(buf, devname))
112 mutex_lock(&dax_bus_lock);
113 dax_id = __dax_match_id(dax_drv, buf);
115 if (action == ID_ADD) {
116 dax_id = kzalloc(sizeof(*dax_id), GFP_KERNEL);
118 strscpy(dax_id->dev_name, buf, DAX_NAME_LEN);
119 list_add(&dax_id->list, &dax_drv->ids);
123 } else if (action == ID_REMOVE) {
124 list_del(&dax_id->list);
127 mutex_unlock(&dax_bus_lock);
131 if (action == ID_ADD)
132 rc = driver_attach(drv);
138 static ssize_t new_id_store(struct device_driver *drv, const char *buf,
141 return do_id_store(drv, buf, count, ID_ADD);
143 static DRIVER_ATTR_WO(new_id);
145 static ssize_t remove_id_store(struct device_driver *drv, const char *buf,
148 return do_id_store(drv, buf, count, ID_REMOVE);
150 static DRIVER_ATTR_WO(remove_id);
152 static struct attribute *dax_drv_attrs[] = {
153 &driver_attr_new_id.attr,
154 &driver_attr_remove_id.attr,
157 ATTRIBUTE_GROUPS(dax_drv);
159 static int dax_bus_match(struct device *dev, struct device_driver *drv);
162 * Static dax regions are regions created by an external subsystem
163 * nvdimm where a single range is assigned. Its boundaries are by the external
164 * subsystem and are usually limited to one physical memory range. For example,
165 * for PMEM it is usually defined by NVDIMM Namespace boundaries (i.e. a
166 * single contiguous range)
168 * On dynamic dax regions, the assigned region can be partitioned by dax core
169 * into multiple subdivisions. A subdivision is represented into one
170 * /dev/daxN.M device composed by one or more potentially discontiguous ranges.
172 * When allocating a dax region, drivers must set whether it's static
173 * (IORESOURCE_DAX_STATIC). On static dax devices, the @pgmap is pre-assigned
174 * to dax core when calling devm_create_dev_dax(), whereas in dynamic dax
175 * devices it is NULL but afterwards allocated by dax core on device ->probe().
176 * Care is needed to make sure that dynamic dax devices are torn down with a
177 * cleared @pgmap field (see kill_dev_dax()).
179 static bool is_static(struct dax_region *dax_region)
181 return (dax_region->res.flags & IORESOURCE_DAX_STATIC) != 0;
184 bool static_dev_dax(struct dev_dax *dev_dax)
186 return is_static(dev_dax->region);
188 EXPORT_SYMBOL_GPL(static_dev_dax);
190 static u64 dev_dax_size(struct dev_dax *dev_dax)
195 WARN_ON_ONCE(!rwsem_is_locked(&dax_dev_rwsem));
197 for (i = 0; i < dev_dax->nr_range; i++)
198 size += range_len(&dev_dax->ranges[i].range);
203 static int dax_bus_probe(struct device *dev)
205 struct dax_device_driver *dax_drv = to_dax_drv(dev->driver);
206 struct dev_dax *dev_dax = to_dev_dax(dev);
207 struct dax_region *dax_region = dev_dax->region;
211 rc = down_read_interruptible(&dax_dev_rwsem);
214 size = dev_dax_size(dev_dax);
215 up_read(&dax_dev_rwsem);
217 if (size == 0 || dev_dax->id < 0)
220 rc = dax_drv->probe(dev_dax);
222 if (rc || is_static(dax_region))
226 * Track new seed creation only after successful probe of the
229 if (dax_region->seed == dev)
230 dax_region->seed = NULL;
235 static void dax_bus_remove(struct device *dev)
237 struct dax_device_driver *dax_drv = to_dax_drv(dev->driver);
238 struct dev_dax *dev_dax = to_dev_dax(dev);
241 dax_drv->remove(dev_dax);
244 static const struct bus_type dax_bus_type = {
246 .uevent = dax_bus_uevent,
247 .match = dax_bus_match,
248 .probe = dax_bus_probe,
249 .remove = dax_bus_remove,
250 .drv_groups = dax_drv_groups,
253 static int dax_bus_match(struct device *dev, struct device_driver *drv)
255 struct dax_device_driver *dax_drv = to_dax_drv(drv);
257 if (dax_match_id(dax_drv, dev))
259 return dax_match_type(dax_drv, dev);
263 * Rely on the fact that drvdata is set before the attributes are
264 * registered, and that the attributes are unregistered before drvdata
265 * is cleared to assume that drvdata is always valid.
267 static ssize_t id_show(struct device *dev,
268 struct device_attribute *attr, char *buf)
270 struct dax_region *dax_region = dev_get_drvdata(dev);
272 return sysfs_emit(buf, "%d\n", dax_region->id);
274 static DEVICE_ATTR_RO(id);
276 static ssize_t region_size_show(struct device *dev,
277 struct device_attribute *attr, char *buf)
279 struct dax_region *dax_region = dev_get_drvdata(dev);
281 return sysfs_emit(buf, "%llu\n",
282 (unsigned long long)resource_size(&dax_region->res));
284 static struct device_attribute dev_attr_region_size = __ATTR(size, 0444,
285 region_size_show, NULL);
287 static ssize_t region_align_show(struct device *dev,
288 struct device_attribute *attr, char *buf)
290 struct dax_region *dax_region = dev_get_drvdata(dev);
292 return sysfs_emit(buf, "%u\n", dax_region->align);
294 static struct device_attribute dev_attr_region_align =
295 __ATTR(align, 0400, region_align_show, NULL);
297 #define for_each_dax_region_resource(dax_region, res) \
298 for (res = (dax_region)->res.child; res; res = res->sibling)
300 static unsigned long long dax_region_avail_size(struct dax_region *dax_region)
302 resource_size_t size = resource_size(&dax_region->res);
303 struct resource *res;
305 WARN_ON_ONCE(!rwsem_is_locked(&dax_region_rwsem));
307 for_each_dax_region_resource(dax_region, res)
308 size -= resource_size(res);
312 static ssize_t available_size_show(struct device *dev,
313 struct device_attribute *attr, char *buf)
315 struct dax_region *dax_region = dev_get_drvdata(dev);
316 unsigned long long size;
319 rc = down_read_interruptible(&dax_region_rwsem);
322 size = dax_region_avail_size(dax_region);
323 up_read(&dax_region_rwsem);
325 return sysfs_emit(buf, "%llu\n", size);
327 static DEVICE_ATTR_RO(available_size);
329 static ssize_t seed_show(struct device *dev,
330 struct device_attribute *attr, char *buf)
332 struct dax_region *dax_region = dev_get_drvdata(dev);
336 if (is_static(dax_region))
339 rc = down_read_interruptible(&dax_region_rwsem);
342 seed = dax_region->seed;
343 rc = sysfs_emit(buf, "%s\n", seed ? dev_name(seed) : "");
344 up_read(&dax_region_rwsem);
348 static DEVICE_ATTR_RO(seed);
350 static ssize_t create_show(struct device *dev,
351 struct device_attribute *attr, char *buf)
353 struct dax_region *dax_region = dev_get_drvdata(dev);
354 struct device *youngest;
357 if (is_static(dax_region))
360 rc = down_read_interruptible(&dax_region_rwsem);
363 youngest = dax_region->youngest;
364 rc = sysfs_emit(buf, "%s\n", youngest ? dev_name(youngest) : "");
365 up_read(&dax_region_rwsem);
370 static struct dev_dax *__devm_create_dev_dax(struct dev_dax_data *data);
372 static ssize_t create_store(struct device *dev, struct device_attribute *attr,
373 const char *buf, size_t len)
375 struct dax_region *dax_region = dev_get_drvdata(dev);
376 unsigned long long avail;
380 if (is_static(dax_region))
383 rc = kstrtoint(buf, 0, &val);
389 rc = down_write_killable(&dax_region_rwsem);
392 avail = dax_region_avail_size(dax_region);
396 struct dev_dax_data data = {
397 .dax_region = dax_region,
400 .memmap_on_memory = false,
402 struct dev_dax *dev_dax = __devm_create_dev_dax(&data);
405 rc = PTR_ERR(dev_dax);
408 * In support of crafting multiple new devices
409 * simultaneously multiple seeds can be created,
410 * but only the first one that has not been
411 * successfully bound is tracked as the region
414 if (!dax_region->seed)
415 dax_region->seed = &dev_dax->dev;
416 dax_region->youngest = &dev_dax->dev;
420 up_write(&dax_region_rwsem);
424 static DEVICE_ATTR_RW(create);
426 void kill_dev_dax(struct dev_dax *dev_dax)
428 struct dax_device *dax_dev = dev_dax->dax_dev;
429 struct inode *inode = dax_inode(dax_dev);
432 unmap_mapping_range(inode->i_mapping, 0, 0, 1);
435 * Dynamic dax region have the pgmap allocated via dev_kzalloc()
436 * and thus freed by devm. Clear the pgmap to not have stale pgmap
437 * ranges on probe() from previous reconfigurations of region devices.
439 if (!static_dev_dax(dev_dax))
440 dev_dax->pgmap = NULL;
442 EXPORT_SYMBOL_GPL(kill_dev_dax);
444 static void trim_dev_dax_range(struct dev_dax *dev_dax)
446 int i = dev_dax->nr_range - 1;
447 struct range *range = &dev_dax->ranges[i].range;
448 struct dax_region *dax_region = dev_dax->region;
450 WARN_ON_ONCE(!rwsem_is_locked(&dax_region_rwsem));
451 dev_dbg(&dev_dax->dev, "delete range[%d]: %#llx:%#llx\n", i,
452 (unsigned long long)range->start,
453 (unsigned long long)range->end);
455 __release_region(&dax_region->res, range->start, range_len(range));
456 if (--dev_dax->nr_range == 0) {
457 kfree(dev_dax->ranges);
458 dev_dax->ranges = NULL;
462 static void free_dev_dax_ranges(struct dev_dax *dev_dax)
464 while (dev_dax->nr_range)
465 trim_dev_dax_range(dev_dax);
468 static void __unregister_dev_dax(void *dev)
470 struct dev_dax *dev_dax = to_dev_dax(dev);
472 dev_dbg(dev, "%s\n", __func__);
474 kill_dev_dax(dev_dax);
476 free_dev_dax_ranges(dev_dax);
480 static void unregister_dev_dax(void *dev)
482 if (rwsem_is_locked(&dax_region_rwsem))
483 return __unregister_dev_dax(dev);
485 if (WARN_ON_ONCE(down_write_killable(&dax_region_rwsem) != 0))
487 __unregister_dev_dax(dev);
488 up_write(&dax_region_rwsem);
491 static void dax_region_free(struct kref *kref)
493 struct dax_region *dax_region;
495 dax_region = container_of(kref, struct dax_region, kref);
499 static void dax_region_put(struct dax_region *dax_region)
501 kref_put(&dax_region->kref, dax_region_free);
504 /* a return value >= 0 indicates this invocation invalidated the id */
505 static int __free_dev_dax_id(struct dev_dax *dev_dax)
507 struct dax_region *dax_region;
508 int rc = dev_dax->id;
510 WARN_ON_ONCE(!rwsem_is_locked(&dax_dev_rwsem));
512 if (!dev_dax->dyn_id || dev_dax->id < 0)
514 dax_region = dev_dax->region;
515 ida_free(&dax_region->ida, dev_dax->id);
516 dax_region_put(dax_region);
521 static int free_dev_dax_id(struct dev_dax *dev_dax)
525 rc = down_write_killable(&dax_dev_rwsem);
528 rc = __free_dev_dax_id(dev_dax);
529 up_write(&dax_dev_rwsem);
533 static int alloc_dev_dax_id(struct dev_dax *dev_dax)
535 struct dax_region *dax_region = dev_dax->region;
538 id = ida_alloc(&dax_region->ida, GFP_KERNEL);
541 kref_get(&dax_region->kref);
542 dev_dax->dyn_id = true;
547 static ssize_t delete_store(struct device *dev, struct device_attribute *attr,
548 const char *buf, size_t len)
550 struct dax_region *dax_region = dev_get_drvdata(dev);
551 struct dev_dax *dev_dax;
552 struct device *victim;
556 if (is_static(dax_region))
559 victim = device_find_child_by_name(dax_region->dev, buf);
563 rc = down_write_killable(&dax_region_rwsem);
566 rc = down_write_killable(&dax_dev_rwsem);
568 up_write(&dax_region_rwsem);
571 dev_dax = to_dev_dax(victim);
572 if (victim->driver || dev_dax_size(dev_dax))
576 * Invalidate the device so it does not become active
577 * again, but always preserve device-id-0 so that
578 * /sys/bus/dax/ is guaranteed to be populated while any
579 * dax_region is registered.
581 if (dev_dax->id > 0) {
582 do_del = __free_dev_dax_id(dev_dax) >= 0;
584 if (dax_region->seed == victim)
585 dax_region->seed = NULL;
586 if (dax_region->youngest == victim)
587 dax_region->youngest = NULL;
591 up_write(&dax_dev_rwsem);
593 /* won the race to invalidate the device, clean it up */
595 devm_release_action(dev, unregister_dev_dax, victim);
596 up_write(&dax_region_rwsem);
601 static DEVICE_ATTR_WO(delete);
603 static umode_t dax_region_visible(struct kobject *kobj, struct attribute *a,
606 struct device *dev = container_of(kobj, struct device, kobj);
607 struct dax_region *dax_region = dev_get_drvdata(dev);
609 if (is_static(dax_region))
610 if (a == &dev_attr_available_size.attr
611 || a == &dev_attr_create.attr
612 || a == &dev_attr_seed.attr
613 || a == &dev_attr_delete.attr)
618 static struct attribute *dax_region_attributes[] = {
619 &dev_attr_available_size.attr,
620 &dev_attr_region_size.attr,
621 &dev_attr_region_align.attr,
622 &dev_attr_create.attr,
624 &dev_attr_delete.attr,
629 static const struct attribute_group dax_region_attribute_group = {
630 .name = "dax_region",
631 .attrs = dax_region_attributes,
632 .is_visible = dax_region_visible,
635 static const struct attribute_group *dax_region_attribute_groups[] = {
636 &dax_region_attribute_group,
640 static void dax_region_unregister(void *region)
642 struct dax_region *dax_region = region;
644 sysfs_remove_groups(&dax_region->dev->kobj,
645 dax_region_attribute_groups);
646 dax_region_put(dax_region);
649 struct dax_region *alloc_dax_region(struct device *parent, int region_id,
650 struct range *range, int target_node, unsigned int align,
653 struct dax_region *dax_region;
656 * The DAX core assumes that it can store its private data in
657 * parent->driver_data. This WARN is a reminder / safeguard for
658 * developers of device-dax drivers.
660 if (dev_get_drvdata(parent)) {
661 dev_WARN(parent, "dax core failed to setup private data\n");
665 if (!IS_ALIGNED(range->start, align)
666 || !IS_ALIGNED(range_len(range), align))
669 dax_region = kzalloc(sizeof(*dax_region), GFP_KERNEL);
673 dev_set_drvdata(parent, dax_region);
674 kref_init(&dax_region->kref);
675 dax_region->id = region_id;
676 dax_region->align = align;
677 dax_region->dev = parent;
678 dax_region->target_node = target_node;
679 ida_init(&dax_region->ida);
680 dax_region->res = (struct resource) {
681 .start = range->start,
683 .flags = IORESOURCE_MEM | flags,
686 if (sysfs_create_groups(&parent->kobj, dax_region_attribute_groups)) {
691 if (devm_add_action_or_reset(parent, dax_region_unregister, dax_region))
695 EXPORT_SYMBOL_GPL(alloc_dax_region);
697 static void dax_mapping_release(struct device *dev)
699 struct dax_mapping *mapping = to_dax_mapping(dev);
700 struct device *parent = dev->parent;
701 struct dev_dax *dev_dax = to_dev_dax(parent);
703 ida_free(&dev_dax->ida, mapping->id);
708 static void __unregister_dax_mapping(void *data)
710 struct device *dev = data;
711 struct dax_mapping *mapping = to_dax_mapping(dev);
712 struct dev_dax *dev_dax = to_dev_dax(dev->parent);
714 dev_dbg(dev, "%s\n", __func__);
716 WARN_ON_ONCE(!rwsem_is_locked(&dax_region_rwsem));
718 dev_dax->ranges[mapping->range_id].mapping = NULL;
719 mapping->range_id = -1;
721 device_unregister(dev);
724 static void unregister_dax_mapping(void *data)
726 if (rwsem_is_locked(&dax_region_rwsem))
727 return __unregister_dax_mapping(data);
729 if (WARN_ON_ONCE(down_write_killable(&dax_region_rwsem) != 0))
731 __unregister_dax_mapping(data);
732 up_write(&dax_region_rwsem);
735 static struct dev_dax_range *get_dax_range(struct device *dev)
737 struct dax_mapping *mapping = to_dax_mapping(dev);
738 struct dev_dax *dev_dax = to_dev_dax(dev->parent);
741 rc = down_write_killable(&dax_region_rwsem);
744 if (mapping->range_id < 0) {
745 up_write(&dax_region_rwsem);
749 return &dev_dax->ranges[mapping->range_id];
752 static void put_dax_range(void)
754 up_write(&dax_region_rwsem);
757 static ssize_t start_show(struct device *dev,
758 struct device_attribute *attr, char *buf)
760 struct dev_dax_range *dax_range;
763 dax_range = get_dax_range(dev);
766 rc = sysfs_emit(buf, "%#llx\n", dax_range->range.start);
771 static DEVICE_ATTR(start, 0400, start_show, NULL);
773 static ssize_t end_show(struct device *dev,
774 struct device_attribute *attr, char *buf)
776 struct dev_dax_range *dax_range;
779 dax_range = get_dax_range(dev);
782 rc = sysfs_emit(buf, "%#llx\n", dax_range->range.end);
787 static DEVICE_ATTR(end, 0400, end_show, NULL);
789 static ssize_t pgoff_show(struct device *dev,
790 struct device_attribute *attr, char *buf)
792 struct dev_dax_range *dax_range;
795 dax_range = get_dax_range(dev);
798 rc = sysfs_emit(buf, "%#lx\n", dax_range->pgoff);
803 static DEVICE_ATTR(page_offset, 0400, pgoff_show, NULL);
805 static struct attribute *dax_mapping_attributes[] = {
806 &dev_attr_start.attr,
808 &dev_attr_page_offset.attr,
812 static const struct attribute_group dax_mapping_attribute_group = {
813 .attrs = dax_mapping_attributes,
816 static const struct attribute_group *dax_mapping_attribute_groups[] = {
817 &dax_mapping_attribute_group,
821 static struct device_type dax_mapping_type = {
822 .release = dax_mapping_release,
823 .groups = dax_mapping_attribute_groups,
826 static int devm_register_dax_mapping(struct dev_dax *dev_dax, int range_id)
828 struct dax_region *dax_region = dev_dax->region;
829 struct dax_mapping *mapping;
833 WARN_ON_ONCE(!rwsem_is_locked(&dax_region_rwsem));
835 if (dev_WARN_ONCE(&dev_dax->dev, !dax_region->dev->driver,
836 "region disabled\n"))
839 mapping = kzalloc(sizeof(*mapping), GFP_KERNEL);
842 mapping->range_id = range_id;
843 mapping->id = ida_alloc(&dev_dax->ida, GFP_KERNEL);
844 if (mapping->id < 0) {
848 dev_dax->ranges[range_id].mapping = mapping;
850 device_initialize(dev);
851 dev->parent = &dev_dax->dev;
852 get_device(dev->parent);
853 dev->type = &dax_mapping_type;
854 dev_set_name(dev, "mapping%d", mapping->id);
855 rc = device_add(dev);
861 rc = devm_add_action_or_reset(dax_region->dev, unregister_dax_mapping,
868 static int alloc_dev_dax_range(struct dev_dax *dev_dax, u64 start,
869 resource_size_t size)
871 struct dax_region *dax_region = dev_dax->region;
872 struct resource *res = &dax_region->res;
873 struct device *dev = &dev_dax->dev;
874 struct dev_dax_range *ranges;
875 unsigned long pgoff = 0;
876 struct resource *alloc;
879 WARN_ON_ONCE(!rwsem_is_locked(&dax_region_rwsem));
881 /* handle the seed alloc special case */
883 if (dev_WARN_ONCE(dev, dev_dax->nr_range,
884 "0-size allocation must be first\n"))
886 /* nr_range == 0 is elsewhere special cased as 0-size device */
890 alloc = __request_region(res, start, size, dev_name(dev), 0);
894 ranges = krealloc(dev_dax->ranges, sizeof(*ranges)
895 * (dev_dax->nr_range + 1), GFP_KERNEL);
897 __release_region(res, alloc->start, resource_size(alloc));
901 for (i = 0; i < dev_dax->nr_range; i++)
902 pgoff += PHYS_PFN(range_len(&ranges[i].range));
903 dev_dax->ranges = ranges;
904 ranges[dev_dax->nr_range++] = (struct dev_dax_range) {
907 .start = alloc->start,
912 dev_dbg(dev, "alloc range[%d]: %pa:%pa\n", dev_dax->nr_range - 1,
913 &alloc->start, &alloc->end);
915 * A dev_dax instance must be registered before mapping device
916 * children can be added. Defer to devm_create_dev_dax() to add
917 * the initial mapping device.
919 if (!device_is_registered(&dev_dax->dev))
922 rc = devm_register_dax_mapping(dev_dax, dev_dax->nr_range - 1);
924 trim_dev_dax_range(dev_dax);
929 static int adjust_dev_dax_range(struct dev_dax *dev_dax, struct resource *res, resource_size_t size)
931 int last_range = dev_dax->nr_range - 1;
932 struct dev_dax_range *dax_range = &dev_dax->ranges[last_range];
933 bool is_shrink = resource_size(res) > size;
934 struct range *range = &dax_range->range;
935 struct device *dev = &dev_dax->dev;
938 WARN_ON_ONCE(!rwsem_is_locked(&dax_region_rwsem));
940 if (dev_WARN_ONCE(dev, !size, "deletion is handled by dev_dax_shrink\n"))
943 rc = adjust_resource(res, range->start, size);
947 *range = (struct range) {
948 .start = range->start,
949 .end = range->start + size - 1,
952 dev_dbg(dev, "%s range[%d]: %#llx:%#llx\n", is_shrink ? "shrink" : "extend",
953 last_range, (unsigned long long) range->start,
954 (unsigned long long) range->end);
959 static ssize_t size_show(struct device *dev,
960 struct device_attribute *attr, char *buf)
962 struct dev_dax *dev_dax = to_dev_dax(dev);
963 unsigned long long size;
966 rc = down_write_killable(&dax_dev_rwsem);
969 size = dev_dax_size(dev_dax);
970 up_write(&dax_dev_rwsem);
972 return sysfs_emit(buf, "%llu\n", size);
975 static bool alloc_is_aligned(struct dev_dax *dev_dax, resource_size_t size)
978 * The minimum mapping granularity for a device instance is a
979 * single subsection, unless the arch says otherwise.
981 return IS_ALIGNED(size, max_t(unsigned long, dev_dax->align, memremap_compat_align()));
984 static int dev_dax_shrink(struct dev_dax *dev_dax, resource_size_t size)
986 resource_size_t to_shrink = dev_dax_size(dev_dax) - size;
987 struct dax_region *dax_region = dev_dax->region;
988 struct device *dev = &dev_dax->dev;
991 for (i = dev_dax->nr_range - 1; i >= 0; i--) {
992 struct range *range = &dev_dax->ranges[i].range;
993 struct dax_mapping *mapping = dev_dax->ranges[i].mapping;
994 struct resource *adjust = NULL, *res;
995 resource_size_t shrink;
997 shrink = min_t(u64, to_shrink, range_len(range));
998 if (shrink >= range_len(range)) {
999 devm_release_action(dax_region->dev,
1000 unregister_dax_mapping, &mapping->dev);
1001 trim_dev_dax_range(dev_dax);
1002 to_shrink -= shrink;
1008 for_each_dax_region_resource(dax_region, res)
1009 if (strcmp(res->name, dev_name(dev)) == 0
1010 && res->start == range->start) {
1015 if (dev_WARN_ONCE(dev, !adjust || i != dev_dax->nr_range - 1,
1016 "failed to find matching resource\n"))
1018 return adjust_dev_dax_range(dev_dax, adjust, range_len(range)
1025 * Only allow adjustments that preserve the relative pgoff of existing
1026 * allocations. I.e. the dev_dax->ranges array is ordered by increasing pgoff.
1028 static bool adjust_ok(struct dev_dax *dev_dax, struct resource *res)
1030 struct dev_dax_range *last;
1033 if (dev_dax->nr_range == 0)
1035 if (strcmp(res->name, dev_name(&dev_dax->dev)) != 0)
1037 last = &dev_dax->ranges[dev_dax->nr_range - 1];
1038 if (last->range.start != res->start || last->range.end != res->end)
1040 for (i = 0; i < dev_dax->nr_range - 1; i++) {
1041 struct dev_dax_range *dax_range = &dev_dax->ranges[i];
1043 if (dax_range->pgoff > last->pgoff)
1050 static ssize_t dev_dax_resize(struct dax_region *dax_region,
1051 struct dev_dax *dev_dax, resource_size_t size)
1053 resource_size_t avail = dax_region_avail_size(dax_region), to_alloc;
1054 resource_size_t dev_size = dev_dax_size(dev_dax);
1055 struct resource *region_res = &dax_region->res;
1056 struct device *dev = &dev_dax->dev;
1057 struct resource *res, *first;
1058 resource_size_t alloc = 0;
1063 if (size == dev_size)
1065 if (size > dev_size && size - dev_size > avail)
1067 if (size < dev_size)
1068 return dev_dax_shrink(dev_dax, size);
1070 to_alloc = size - dev_size;
1071 if (dev_WARN_ONCE(dev, !alloc_is_aligned(dev_dax, to_alloc),
1072 "resize of %pa misaligned\n", &to_alloc))
1076 * Expand the device into the unused portion of the region. This
1077 * may involve adjusting the end of an existing resource, or
1078 * allocating a new resource.
1081 first = region_res->child;
1083 return alloc_dev_dax_range(dev_dax, dax_region->res.start, to_alloc);
1086 for (res = first; res; res = res->sibling) {
1087 struct resource *next = res->sibling;
1089 /* space at the beginning of the region */
1090 if (res == first && res->start > dax_region->res.start) {
1091 alloc = min(res->start - dax_region->res.start, to_alloc);
1092 rc = alloc_dev_dax_range(dev_dax, dax_region->res.start, alloc);
1097 /* space between allocations */
1098 if (next && next->start > res->end + 1)
1099 alloc = min(next->start - (res->end + 1), to_alloc);
1101 /* space at the end of the region */
1102 if (!alloc && !next && res->end < region_res->end)
1103 alloc = min(region_res->end - res->end, to_alloc);
1108 if (adjust_ok(dev_dax, res)) {
1109 rc = adjust_dev_dax_range(dev_dax, res, resource_size(res) + alloc);
1112 rc = alloc_dev_dax_range(dev_dax, res->end + 1, alloc);
1123 static ssize_t size_store(struct device *dev, struct device_attribute *attr,
1124 const char *buf, size_t len)
1127 unsigned long long val;
1128 struct dev_dax *dev_dax = to_dev_dax(dev);
1129 struct dax_region *dax_region = dev_dax->region;
1131 rc = kstrtoull(buf, 0, &val);
1135 if (!alloc_is_aligned(dev_dax, val)) {
1136 dev_dbg(dev, "%s: size: %lld misaligned\n", __func__, val);
1140 rc = down_write_killable(&dax_region_rwsem);
1143 if (!dax_region->dev->driver) {
1147 rc = down_write_killable(&dax_dev_rwsem);
1151 rc = dev_dax_resize(dax_region, dev_dax, val);
1154 up_write(&dax_dev_rwsem);
1156 up_write(&dax_region_rwsem);
1162 static DEVICE_ATTR_RW(size);
1164 static ssize_t range_parse(const char *opt, size_t len, struct range *range)
1166 unsigned long long addr = 0;
1167 char *start, *end, *str;
1168 ssize_t rc = -EINVAL;
1170 str = kstrdup(opt, GFP_KERNEL);
1175 start = strsep(&end, "-");
1179 rc = kstrtoull(start, 16, &addr);
1182 range->start = addr;
1184 rc = kstrtoull(end, 16, &addr);
1194 static ssize_t mapping_store(struct device *dev, struct device_attribute *attr,
1195 const char *buf, size_t len)
1197 struct dev_dax *dev_dax = to_dev_dax(dev);
1198 struct dax_region *dax_region = dev_dax->region;
1203 rc = range_parse(buf, len, &r);
1208 rc = down_write_killable(&dax_region_rwsem);
1211 if (!dax_region->dev->driver) {
1212 up_write(&dax_region_rwsem);
1215 rc = down_write_killable(&dax_dev_rwsem);
1217 up_write(&dax_region_rwsem);
1221 to_alloc = range_len(&r);
1222 if (alloc_is_aligned(dev_dax, to_alloc))
1223 rc = alloc_dev_dax_range(dev_dax, r.start, to_alloc);
1224 up_write(&dax_dev_rwsem);
1225 up_write(&dax_region_rwsem);
1227 return rc == 0 ? len : rc;
1229 static DEVICE_ATTR_WO(mapping);
1231 static ssize_t align_show(struct device *dev,
1232 struct device_attribute *attr, char *buf)
1234 struct dev_dax *dev_dax = to_dev_dax(dev);
1236 return sysfs_emit(buf, "%d\n", dev_dax->align);
1239 static ssize_t dev_dax_validate_align(struct dev_dax *dev_dax)
1241 struct device *dev = &dev_dax->dev;
1244 for (i = 0; i < dev_dax->nr_range; i++) {
1245 size_t len = range_len(&dev_dax->ranges[i].range);
1247 if (!alloc_is_aligned(dev_dax, len)) {
1248 dev_dbg(dev, "%s: align %u invalid for range %d\n",
1249 __func__, dev_dax->align, i);
1257 static ssize_t align_store(struct device *dev, struct device_attribute *attr,
1258 const char *buf, size_t len)
1260 struct dev_dax *dev_dax = to_dev_dax(dev);
1261 struct dax_region *dax_region = dev_dax->region;
1262 unsigned long val, align_save;
1265 rc = kstrtoul(buf, 0, &val);
1269 if (!dax_align_valid(val))
1272 rc = down_write_killable(&dax_region_rwsem);
1275 if (!dax_region->dev->driver) {
1276 up_write(&dax_region_rwsem);
1280 rc = down_write_killable(&dax_dev_rwsem);
1282 up_write(&dax_region_rwsem);
1290 align_save = dev_dax->align;
1291 dev_dax->align = val;
1292 rc = dev_dax_validate_align(dev_dax);
1294 dev_dax->align = align_save;
1296 up_write(&dax_dev_rwsem);
1297 up_write(&dax_region_rwsem);
1298 return rc == 0 ? len : rc;
1300 static DEVICE_ATTR_RW(align);
1302 static int dev_dax_target_node(struct dev_dax *dev_dax)
1304 struct dax_region *dax_region = dev_dax->region;
1306 return dax_region->target_node;
1309 static ssize_t target_node_show(struct device *dev,
1310 struct device_attribute *attr, char *buf)
1312 struct dev_dax *dev_dax = to_dev_dax(dev);
1314 return sysfs_emit(buf, "%d\n", dev_dax_target_node(dev_dax));
1316 static DEVICE_ATTR_RO(target_node);
1318 static ssize_t resource_show(struct device *dev,
1319 struct device_attribute *attr, char *buf)
1321 struct dev_dax *dev_dax = to_dev_dax(dev);
1322 struct dax_region *dax_region = dev_dax->region;
1323 unsigned long long start;
1325 if (dev_dax->nr_range < 1)
1326 start = dax_region->res.start;
1328 start = dev_dax->ranges[0].range.start;
1330 return sysfs_emit(buf, "%#llx\n", start);
1332 static DEVICE_ATTR(resource, 0400, resource_show, NULL);
1334 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
1338 * We only ever expect to handle device-dax instances, i.e. the
1339 * @type argument to MODULE_ALIAS_DAX_DEVICE() is always zero
1341 return sysfs_emit(buf, DAX_DEVICE_MODALIAS_FMT "\n", 0);
1343 static DEVICE_ATTR_RO(modalias);
1345 static ssize_t numa_node_show(struct device *dev,
1346 struct device_attribute *attr, char *buf)
1348 return sysfs_emit(buf, "%d\n", dev_to_node(dev));
1350 static DEVICE_ATTR_RO(numa_node);
1352 static ssize_t memmap_on_memory_show(struct device *dev,
1353 struct device_attribute *attr, char *buf)
1355 struct dev_dax *dev_dax = to_dev_dax(dev);
1357 return sysfs_emit(buf, "%d\n", dev_dax->memmap_on_memory);
1360 static ssize_t memmap_on_memory_store(struct device *dev,
1361 struct device_attribute *attr,
1362 const char *buf, size_t len)
1364 struct dev_dax *dev_dax = to_dev_dax(dev);
1368 rc = kstrtobool(buf, &val);
1372 if (val == true && !mhp_supports_memmap_on_memory()) {
1373 dev_dbg(dev, "memmap_on_memory is not available\n");
1377 rc = down_write_killable(&dax_dev_rwsem);
1381 if (dev_dax->memmap_on_memory != val && dev->driver &&
1382 to_dax_drv(dev->driver)->type == DAXDRV_KMEM_TYPE) {
1383 up_write(&dax_dev_rwsem);
1387 dev_dax->memmap_on_memory = val;
1388 up_write(&dax_dev_rwsem);
1392 static DEVICE_ATTR_RW(memmap_on_memory);
1394 static umode_t dev_dax_visible(struct kobject *kobj, struct attribute *a, int n)
1396 struct device *dev = container_of(kobj, struct device, kobj);
1397 struct dev_dax *dev_dax = to_dev_dax(dev);
1398 struct dax_region *dax_region = dev_dax->region;
1400 if (a == &dev_attr_target_node.attr && dev_dax_target_node(dev_dax) < 0)
1402 if (a == &dev_attr_numa_node.attr && !IS_ENABLED(CONFIG_NUMA))
1404 if (a == &dev_attr_mapping.attr && is_static(dax_region))
1406 if ((a == &dev_attr_align.attr ||
1407 a == &dev_attr_size.attr) && is_static(dax_region))
1412 static struct attribute *dev_dax_attributes[] = {
1413 &dev_attr_modalias.attr,
1414 &dev_attr_size.attr,
1415 &dev_attr_mapping.attr,
1416 &dev_attr_target_node.attr,
1417 &dev_attr_align.attr,
1418 &dev_attr_resource.attr,
1419 &dev_attr_numa_node.attr,
1420 &dev_attr_memmap_on_memory.attr,
1424 static const struct attribute_group dev_dax_attribute_group = {
1425 .attrs = dev_dax_attributes,
1426 .is_visible = dev_dax_visible,
1429 static const struct attribute_group *dax_attribute_groups[] = {
1430 &dev_dax_attribute_group,
1434 static void dev_dax_release(struct device *dev)
1436 struct dev_dax *dev_dax = to_dev_dax(dev);
1437 struct dax_device *dax_dev = dev_dax->dax_dev;
1440 free_dev_dax_id(dev_dax);
1441 kfree(dev_dax->pgmap);
1445 static const struct device_type dev_dax_type = {
1446 .release = dev_dax_release,
1447 .groups = dax_attribute_groups,
1450 static struct dev_dax *__devm_create_dev_dax(struct dev_dax_data *data)
1452 struct dax_region *dax_region = data->dax_region;
1453 struct device *parent = dax_region->dev;
1454 struct dax_device *dax_dev;
1455 struct dev_dax *dev_dax;
1456 struct inode *inode;
1460 dev_dax = kzalloc(sizeof(*dev_dax), GFP_KERNEL);
1462 return ERR_PTR(-ENOMEM);
1464 dev_dax->region = dax_region;
1465 if (is_static(dax_region)) {
1466 if (dev_WARN_ONCE(parent, data->id < 0,
1467 "dynamic id specified to static region\n")) {
1472 dev_dax->id = data->id;
1474 if (dev_WARN_ONCE(parent, data->id >= 0,
1475 "static id specified to dynamic region\n")) {
1480 rc = alloc_dev_dax_id(dev_dax);
1485 dev = &dev_dax->dev;
1486 device_initialize(dev);
1487 dev_set_name(dev, "dax%d.%d", dax_region->id, dev_dax->id);
1489 rc = alloc_dev_dax_range(dev_dax, dax_region->res.start, data->size);
1494 dev_WARN_ONCE(parent, !is_static(dax_region),
1495 "custom dev_pagemap requires a static dax_region\n");
1497 dev_dax->pgmap = kmemdup(data->pgmap,
1498 sizeof(struct dev_pagemap), GFP_KERNEL);
1499 if (!dev_dax->pgmap) {
1506 * No dax_operations since there is no access to this device outside of
1507 * mmap of the resulting character device.
1509 dax_dev = alloc_dax(dev_dax, NULL);
1510 if (IS_ERR(dax_dev)) {
1511 rc = PTR_ERR(dax_dev);
1514 set_dax_synchronous(dax_dev);
1515 set_dax_nocache(dax_dev);
1516 set_dax_nomc(dax_dev);
1518 /* a device_dax instance is dead while the driver is not attached */
1521 dev_dax->dax_dev = dax_dev;
1522 dev_dax->target_node = dax_region->target_node;
1523 dev_dax->align = dax_region->align;
1524 ida_init(&dev_dax->ida);
1526 dev_dax->memmap_on_memory = data->memmap_on_memory;
1528 inode = dax_inode(dax_dev);
1529 dev->devt = inode->i_rdev;
1530 dev->bus = &dax_bus_type;
1531 dev->parent = parent;
1532 dev->type = &dev_dax_type;
1534 rc = device_add(dev);
1536 kill_dev_dax(dev_dax);
1541 rc = devm_add_action_or_reset(dax_region->dev, unregister_dev_dax, dev);
1545 /* register mapping device for the initial allocation range */
1546 if (dev_dax->nr_range && range_len(&dev_dax->ranges[0].range)) {
1547 rc = devm_register_dax_mapping(dev_dax, 0);
1555 kfree(dev_dax->pgmap);
1557 free_dev_dax_ranges(dev_dax);
1559 free_dev_dax_id(dev_dax);
1566 struct dev_dax *devm_create_dev_dax(struct dev_dax_data *data)
1568 struct dev_dax *dev_dax;
1571 rc = down_write_killable(&dax_region_rwsem);
1575 dev_dax = __devm_create_dev_dax(data);
1576 up_write(&dax_region_rwsem);
1580 EXPORT_SYMBOL_GPL(devm_create_dev_dax);
1582 int __dax_driver_register(struct dax_device_driver *dax_drv,
1583 struct module *module, const char *mod_name)
1585 struct device_driver *drv = &dax_drv->drv;
1588 * dax_bus_probe() calls dax_drv->probe() unconditionally.
1589 * So better be safe than sorry and ensure it is provided.
1591 if (!dax_drv->probe)
1594 INIT_LIST_HEAD(&dax_drv->ids);
1595 drv->owner = module;
1596 drv->name = mod_name;
1597 drv->mod_name = mod_name;
1598 drv->bus = &dax_bus_type;
1600 return driver_register(drv);
1602 EXPORT_SYMBOL_GPL(__dax_driver_register);
1604 void dax_driver_unregister(struct dax_device_driver *dax_drv)
1606 struct device_driver *drv = &dax_drv->drv;
1607 struct dax_id *dax_id, *_id;
1609 mutex_lock(&dax_bus_lock);
1610 list_for_each_entry_safe(dax_id, _id, &dax_drv->ids, list) {
1611 list_del(&dax_id->list);
1614 mutex_unlock(&dax_bus_lock);
1615 driver_unregister(drv);
1617 EXPORT_SYMBOL_GPL(dax_driver_unregister);
1619 int __init dax_bus_init(void)
1621 return bus_register(&dax_bus_type);
1624 void __exit dax_bus_exit(void)
1626 bus_unregister(&dax_bus_type);