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 struct class *dax_class;
15 static DEFINE_MUTEX(dax_bus_lock);
17 #define DAX_NAME_LEN 30
19 struct list_head list;
20 char dev_name[DAX_NAME_LEN];
23 static int dax_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
26 * We only ever expect to handle device-dax instances, i.e. the
27 * @type argument to MODULE_ALIAS_DAX_DEVICE() is always zero
29 return add_uevent_var(env, "MODALIAS=" DAX_DEVICE_MODALIAS_FMT, 0);
32 static struct dax_device_driver *to_dax_drv(struct device_driver *drv)
34 return container_of(drv, struct dax_device_driver, drv);
37 static struct dax_id *__dax_match_id(struct dax_device_driver *dax_drv,
40 struct dax_id *dax_id;
42 lockdep_assert_held(&dax_bus_lock);
44 list_for_each_entry(dax_id, &dax_drv->ids, list)
45 if (sysfs_streq(dax_id->dev_name, dev_name))
50 static int dax_match_id(struct dax_device_driver *dax_drv, struct device *dev)
54 mutex_lock(&dax_bus_lock);
55 match = !!__dax_match_id(dax_drv, dev_name(dev));
56 mutex_unlock(&dax_bus_lock);
66 static ssize_t do_id_store(struct device_driver *drv, const char *buf,
67 size_t count, enum id_action action)
69 struct dax_device_driver *dax_drv = to_dax_drv(drv);
70 unsigned int region_id, id;
71 char devname[DAX_NAME_LEN];
72 struct dax_id *dax_id;
76 fields = sscanf(buf, "dax%d.%d", ®ion_id, &id);
79 sprintf(devname, "dax%d.%d", region_id, id);
80 if (!sysfs_streq(buf, devname))
83 mutex_lock(&dax_bus_lock);
84 dax_id = __dax_match_id(dax_drv, buf);
86 if (action == ID_ADD) {
87 dax_id = kzalloc(sizeof(*dax_id), GFP_KERNEL);
89 strncpy(dax_id->dev_name, buf, DAX_NAME_LEN);
90 list_add(&dax_id->list, &dax_drv->ids);
94 /* nothing to remove */;
95 } else if (action == ID_REMOVE) {
96 list_del(&dax_id->list);
99 /* dax_id already added */;
100 mutex_unlock(&dax_bus_lock);
104 if (action == ID_ADD)
105 rc = driver_attach(drv);
111 static ssize_t new_id_store(struct device_driver *drv, const char *buf,
114 return do_id_store(drv, buf, count, ID_ADD);
116 static DRIVER_ATTR_WO(new_id);
118 static ssize_t remove_id_store(struct device_driver *drv, const char *buf,
121 return do_id_store(drv, buf, count, ID_REMOVE);
123 static DRIVER_ATTR_WO(remove_id);
125 static struct attribute *dax_drv_attrs[] = {
126 &driver_attr_new_id.attr,
127 &driver_attr_remove_id.attr,
130 ATTRIBUTE_GROUPS(dax_drv);
132 static int dax_bus_match(struct device *dev, struct device_driver *drv);
134 static bool is_static(struct dax_region *dax_region)
136 return (dax_region->res.flags & IORESOURCE_DAX_STATIC) != 0;
139 static u64 dev_dax_size(struct dev_dax *dev_dax)
144 device_lock_assert(&dev_dax->dev);
146 for (i = 0; i < dev_dax->nr_range; i++)
147 size += range_len(&dev_dax->ranges[i].range);
152 static int dax_bus_probe(struct device *dev)
154 struct dax_device_driver *dax_drv = to_dax_drv(dev->driver);
155 struct dev_dax *dev_dax = to_dev_dax(dev);
156 struct dax_region *dax_region = dev_dax->region;
159 if (dev_dax_size(dev_dax) == 0 || dev_dax->id < 0)
162 rc = dax_drv->probe(dev_dax);
164 if (rc || is_static(dax_region))
168 * Track new seed creation only after successful probe of the
171 if (dax_region->seed == dev)
172 dax_region->seed = NULL;
177 static int dax_bus_remove(struct device *dev)
179 struct dax_device_driver *dax_drv = to_dax_drv(dev->driver);
180 struct dev_dax *dev_dax = to_dev_dax(dev);
183 dax_drv->remove(dev_dax);
188 static struct bus_type dax_bus_type = {
190 .uevent = dax_bus_uevent,
191 .match = dax_bus_match,
192 .probe = dax_bus_probe,
193 .remove = dax_bus_remove,
194 .drv_groups = dax_drv_groups,
197 static int dax_bus_match(struct device *dev, struct device_driver *drv)
199 struct dax_device_driver *dax_drv = to_dax_drv(drv);
202 * All but the 'device-dax' driver, which has 'match_always'
203 * set, requires an exact id match.
205 if (dax_drv->match_always)
208 return dax_match_id(dax_drv, dev);
212 * Rely on the fact that drvdata is set before the attributes are
213 * registered, and that the attributes are unregistered before drvdata
214 * is cleared to assume that drvdata is always valid.
216 static ssize_t id_show(struct device *dev,
217 struct device_attribute *attr, char *buf)
219 struct dax_region *dax_region = dev_get_drvdata(dev);
221 return sprintf(buf, "%d\n", dax_region->id);
223 static DEVICE_ATTR_RO(id);
225 static ssize_t region_size_show(struct device *dev,
226 struct device_attribute *attr, char *buf)
228 struct dax_region *dax_region = dev_get_drvdata(dev);
230 return sprintf(buf, "%llu\n", (unsigned long long)
231 resource_size(&dax_region->res));
233 static struct device_attribute dev_attr_region_size = __ATTR(size, 0444,
234 region_size_show, NULL);
236 static ssize_t region_align_show(struct device *dev,
237 struct device_attribute *attr, char *buf)
239 struct dax_region *dax_region = dev_get_drvdata(dev);
241 return sprintf(buf, "%u\n", dax_region->align);
243 static struct device_attribute dev_attr_region_align =
244 __ATTR(align, 0400, region_align_show, NULL);
246 #define for_each_dax_region_resource(dax_region, res) \
247 for (res = (dax_region)->res.child; res; res = res->sibling)
249 static unsigned long long dax_region_avail_size(struct dax_region *dax_region)
251 resource_size_t size = resource_size(&dax_region->res);
252 struct resource *res;
254 device_lock_assert(dax_region->dev);
256 for_each_dax_region_resource(dax_region, res)
257 size -= resource_size(res);
261 static ssize_t available_size_show(struct device *dev,
262 struct device_attribute *attr, char *buf)
264 struct dax_region *dax_region = dev_get_drvdata(dev);
265 unsigned long long size;
268 size = dax_region_avail_size(dax_region);
271 return sprintf(buf, "%llu\n", size);
273 static DEVICE_ATTR_RO(available_size);
275 static ssize_t seed_show(struct device *dev,
276 struct device_attribute *attr, char *buf)
278 struct dax_region *dax_region = dev_get_drvdata(dev);
282 if (is_static(dax_region))
286 seed = dax_region->seed;
287 rc = sprintf(buf, "%s\n", seed ? dev_name(seed) : "");
292 static DEVICE_ATTR_RO(seed);
294 static ssize_t create_show(struct device *dev,
295 struct device_attribute *attr, char *buf)
297 struct dax_region *dax_region = dev_get_drvdata(dev);
298 struct device *youngest;
301 if (is_static(dax_region))
305 youngest = dax_region->youngest;
306 rc = sprintf(buf, "%s\n", youngest ? dev_name(youngest) : "");
312 static ssize_t create_store(struct device *dev, struct device_attribute *attr,
313 const char *buf, size_t len)
315 struct dax_region *dax_region = dev_get_drvdata(dev);
316 unsigned long long avail;
320 if (is_static(dax_region))
323 rc = kstrtoint(buf, 0, &val);
330 avail = dax_region_avail_size(dax_region);
334 struct dev_dax_data data = {
335 .dax_region = dax_region,
339 struct dev_dax *dev_dax = devm_create_dev_dax(&data);
342 rc = PTR_ERR(dev_dax);
345 * In support of crafting multiple new devices
346 * simultaneously multiple seeds can be created,
347 * but only the first one that has not been
348 * successfully bound is tracked as the region
351 if (!dax_region->seed)
352 dax_region->seed = &dev_dax->dev;
353 dax_region->youngest = &dev_dax->dev;
361 static DEVICE_ATTR_RW(create);
363 void kill_dev_dax(struct dev_dax *dev_dax)
365 struct dax_device *dax_dev = dev_dax->dax_dev;
366 struct inode *inode = dax_inode(dax_dev);
369 unmap_mapping_range(inode->i_mapping, 0, 0, 1);
371 EXPORT_SYMBOL_GPL(kill_dev_dax);
373 static void trim_dev_dax_range(struct dev_dax *dev_dax)
375 int i = dev_dax->nr_range - 1;
376 struct range *range = &dev_dax->ranges[i].range;
377 struct dax_region *dax_region = dev_dax->region;
379 device_lock_assert(dax_region->dev);
380 dev_dbg(&dev_dax->dev, "delete range[%d]: %#llx:%#llx\n", i,
381 (unsigned long long)range->start,
382 (unsigned long long)range->end);
384 __release_region(&dax_region->res, range->start, range_len(range));
385 if (--dev_dax->nr_range == 0) {
386 kfree(dev_dax->ranges);
387 dev_dax->ranges = NULL;
391 static void free_dev_dax_ranges(struct dev_dax *dev_dax)
393 while (dev_dax->nr_range)
394 trim_dev_dax_range(dev_dax);
397 static void unregister_dev_dax(void *dev)
399 struct dev_dax *dev_dax = to_dev_dax(dev);
401 dev_dbg(dev, "%s\n", __func__);
403 kill_dev_dax(dev_dax);
404 free_dev_dax_ranges(dev_dax);
409 /* a return value >= 0 indicates this invocation invalidated the id */
410 static int __free_dev_dax_id(struct dev_dax *dev_dax)
412 struct dax_region *dax_region = dev_dax->region;
413 struct device *dev = &dev_dax->dev;
414 int rc = dev_dax->id;
416 device_lock_assert(dev);
418 if (is_static(dax_region) || dev_dax->id < 0)
420 ida_free(&dax_region->ida, dev_dax->id);
425 static int free_dev_dax_id(struct dev_dax *dev_dax)
427 struct device *dev = &dev_dax->dev;
431 rc = __free_dev_dax_id(dev_dax);
436 static ssize_t delete_store(struct device *dev, struct device_attribute *attr,
437 const char *buf, size_t len)
439 struct dax_region *dax_region = dev_get_drvdata(dev);
440 struct dev_dax *dev_dax;
441 struct device *victim;
445 if (is_static(dax_region))
448 victim = device_find_child_by_name(dax_region->dev, buf);
454 dev_dax = to_dev_dax(victim);
455 if (victim->driver || dev_dax_size(dev_dax))
459 * Invalidate the device so it does not become active
460 * again, but always preserve device-id-0 so that
461 * /sys/bus/dax/ is guaranteed to be populated while any
462 * dax_region is registered.
464 if (dev_dax->id > 0) {
465 do_del = __free_dev_dax_id(dev_dax) >= 0;
467 if (dax_region->seed == victim)
468 dax_region->seed = NULL;
469 if (dax_region->youngest == victim)
470 dax_region->youngest = NULL;
474 device_unlock(victim);
476 /* won the race to invalidate the device, clean it up */
478 devm_release_action(dev, unregister_dev_dax, victim);
484 static DEVICE_ATTR_WO(delete);
486 static umode_t dax_region_visible(struct kobject *kobj, struct attribute *a,
489 struct device *dev = container_of(kobj, struct device, kobj);
490 struct dax_region *dax_region = dev_get_drvdata(dev);
492 if (is_static(dax_region))
493 if (a == &dev_attr_available_size.attr
494 || a == &dev_attr_create.attr
495 || a == &dev_attr_seed.attr
496 || a == &dev_attr_delete.attr)
501 static struct attribute *dax_region_attributes[] = {
502 &dev_attr_available_size.attr,
503 &dev_attr_region_size.attr,
504 &dev_attr_region_align.attr,
505 &dev_attr_create.attr,
507 &dev_attr_delete.attr,
512 static const struct attribute_group dax_region_attribute_group = {
513 .name = "dax_region",
514 .attrs = dax_region_attributes,
515 .is_visible = dax_region_visible,
518 static const struct attribute_group *dax_region_attribute_groups[] = {
519 &dax_region_attribute_group,
523 static void dax_region_free(struct kref *kref)
525 struct dax_region *dax_region;
527 dax_region = container_of(kref, struct dax_region, kref);
531 void dax_region_put(struct dax_region *dax_region)
533 kref_put(&dax_region->kref, dax_region_free);
535 EXPORT_SYMBOL_GPL(dax_region_put);
537 static void dax_region_unregister(void *region)
539 struct dax_region *dax_region = region;
541 sysfs_remove_groups(&dax_region->dev->kobj,
542 dax_region_attribute_groups);
543 dax_region_put(dax_region);
546 struct dax_region *alloc_dax_region(struct device *parent, int region_id,
547 struct range *range, int target_node, unsigned int align,
550 struct dax_region *dax_region;
553 * The DAX core assumes that it can store its private data in
554 * parent->driver_data. This WARN is a reminder / safeguard for
555 * developers of device-dax drivers.
557 if (dev_get_drvdata(parent)) {
558 dev_WARN(parent, "dax core failed to setup private data\n");
562 if (!IS_ALIGNED(range->start, align)
563 || !IS_ALIGNED(range_len(range), align))
566 dax_region = kzalloc(sizeof(*dax_region), GFP_KERNEL);
570 dev_set_drvdata(parent, dax_region);
571 kref_init(&dax_region->kref);
572 dax_region->id = region_id;
573 dax_region->align = align;
574 dax_region->dev = parent;
575 dax_region->target_node = target_node;
576 ida_init(&dax_region->ida);
577 dax_region->res = (struct resource) {
578 .start = range->start,
580 .flags = IORESOURCE_MEM | flags,
583 if (sysfs_create_groups(&parent->kobj, dax_region_attribute_groups)) {
588 kref_get(&dax_region->kref);
589 if (devm_add_action_or_reset(parent, dax_region_unregister, dax_region))
593 EXPORT_SYMBOL_GPL(alloc_dax_region);
595 static void dax_mapping_release(struct device *dev)
597 struct dax_mapping *mapping = to_dax_mapping(dev);
598 struct dev_dax *dev_dax = to_dev_dax(dev->parent);
600 ida_free(&dev_dax->ida, mapping->id);
604 static void unregister_dax_mapping(void *data)
606 struct device *dev = data;
607 struct dax_mapping *mapping = to_dax_mapping(dev);
608 struct dev_dax *dev_dax = to_dev_dax(dev->parent);
609 struct dax_region *dax_region = dev_dax->region;
611 dev_dbg(dev, "%s\n", __func__);
613 device_lock_assert(dax_region->dev);
615 dev_dax->ranges[mapping->range_id].mapping = NULL;
616 mapping->range_id = -1;
622 static struct dev_dax_range *get_dax_range(struct device *dev)
624 struct dax_mapping *mapping = to_dax_mapping(dev);
625 struct dev_dax *dev_dax = to_dev_dax(dev->parent);
626 struct dax_region *dax_region = dev_dax->region;
628 device_lock(dax_region->dev);
629 if (mapping->range_id < 0) {
630 device_unlock(dax_region->dev);
634 return &dev_dax->ranges[mapping->range_id];
637 static void put_dax_range(struct dev_dax_range *dax_range)
639 struct dax_mapping *mapping = dax_range->mapping;
640 struct dev_dax *dev_dax = to_dev_dax(mapping->dev.parent);
641 struct dax_region *dax_region = dev_dax->region;
643 device_unlock(dax_region->dev);
646 static ssize_t start_show(struct device *dev,
647 struct device_attribute *attr, char *buf)
649 struct dev_dax_range *dax_range;
652 dax_range = get_dax_range(dev);
655 rc = sprintf(buf, "%#llx\n", dax_range->range.start);
656 put_dax_range(dax_range);
660 static DEVICE_ATTR(start, 0400, start_show, NULL);
662 static ssize_t end_show(struct device *dev,
663 struct device_attribute *attr, char *buf)
665 struct dev_dax_range *dax_range;
668 dax_range = get_dax_range(dev);
671 rc = sprintf(buf, "%#llx\n", dax_range->range.end);
672 put_dax_range(dax_range);
676 static DEVICE_ATTR(end, 0400, end_show, NULL);
678 static ssize_t pgoff_show(struct device *dev,
679 struct device_attribute *attr, char *buf)
681 struct dev_dax_range *dax_range;
684 dax_range = get_dax_range(dev);
687 rc = sprintf(buf, "%#lx\n", dax_range->pgoff);
688 put_dax_range(dax_range);
692 static DEVICE_ATTR(page_offset, 0400, pgoff_show, NULL);
694 static struct attribute *dax_mapping_attributes[] = {
695 &dev_attr_start.attr,
697 &dev_attr_page_offset.attr,
701 static const struct attribute_group dax_mapping_attribute_group = {
702 .attrs = dax_mapping_attributes,
705 static const struct attribute_group *dax_mapping_attribute_groups[] = {
706 &dax_mapping_attribute_group,
710 static struct device_type dax_mapping_type = {
711 .release = dax_mapping_release,
712 .groups = dax_mapping_attribute_groups,
715 static int devm_register_dax_mapping(struct dev_dax *dev_dax, int range_id)
717 struct dax_region *dax_region = dev_dax->region;
718 struct dax_mapping *mapping;
722 device_lock_assert(dax_region->dev);
724 if (dev_WARN_ONCE(&dev_dax->dev, !dax_region->dev->driver,
725 "region disabled\n"))
728 mapping = kzalloc(sizeof(*mapping), GFP_KERNEL);
731 mapping->range_id = range_id;
732 mapping->id = ida_alloc(&dev_dax->ida, GFP_KERNEL);
733 if (mapping->id < 0) {
737 dev_dax->ranges[range_id].mapping = mapping;
739 device_initialize(dev);
740 dev->parent = &dev_dax->dev;
741 dev->type = &dax_mapping_type;
742 dev_set_name(dev, "mapping%d", mapping->id);
743 rc = device_add(dev);
749 rc = devm_add_action_or_reset(dax_region->dev, unregister_dax_mapping,
756 static int alloc_dev_dax_range(struct dev_dax *dev_dax, u64 start,
757 resource_size_t size)
759 struct dax_region *dax_region = dev_dax->region;
760 struct resource *res = &dax_region->res;
761 struct device *dev = &dev_dax->dev;
762 struct dev_dax_range *ranges;
763 unsigned long pgoff = 0;
764 struct resource *alloc;
767 device_lock_assert(dax_region->dev);
769 /* handle the seed alloc special case */
771 if (dev_WARN_ONCE(dev, dev_dax->nr_range,
772 "0-size allocation must be first\n"))
774 /* nr_range == 0 is elsewhere special cased as 0-size device */
778 alloc = __request_region(res, start, size, dev_name(dev), 0);
782 ranges = krealloc(dev_dax->ranges, sizeof(*ranges)
783 * (dev_dax->nr_range + 1), GFP_KERNEL);
785 __release_region(res, alloc->start, resource_size(alloc));
789 for (i = 0; i < dev_dax->nr_range; i++)
790 pgoff += PHYS_PFN(range_len(&ranges[i].range));
791 dev_dax->ranges = ranges;
792 ranges[dev_dax->nr_range++] = (struct dev_dax_range) {
795 .start = alloc->start,
800 dev_dbg(dev, "alloc range[%d]: %pa:%pa\n", dev_dax->nr_range - 1,
801 &alloc->start, &alloc->end);
803 * A dev_dax instance must be registered before mapping device
804 * children can be added. Defer to devm_create_dev_dax() to add
805 * the initial mapping device.
807 if (!device_is_registered(&dev_dax->dev))
810 rc = devm_register_dax_mapping(dev_dax, dev_dax->nr_range - 1);
812 trim_dev_dax_range(dev_dax);
817 static int adjust_dev_dax_range(struct dev_dax *dev_dax, struct resource *res, resource_size_t size)
819 int last_range = dev_dax->nr_range - 1;
820 struct dev_dax_range *dax_range = &dev_dax->ranges[last_range];
821 struct dax_region *dax_region = dev_dax->region;
822 bool is_shrink = resource_size(res) > size;
823 struct range *range = &dax_range->range;
824 struct device *dev = &dev_dax->dev;
827 device_lock_assert(dax_region->dev);
829 if (dev_WARN_ONCE(dev, !size, "deletion is handled by dev_dax_shrink\n"))
832 rc = adjust_resource(res, range->start, size);
836 *range = (struct range) {
837 .start = range->start,
838 .end = range->start + size - 1,
841 dev_dbg(dev, "%s range[%d]: %#llx:%#llx\n", is_shrink ? "shrink" : "extend",
842 last_range, (unsigned long long) range->start,
843 (unsigned long long) range->end);
848 static ssize_t size_show(struct device *dev,
849 struct device_attribute *attr, char *buf)
851 struct dev_dax *dev_dax = to_dev_dax(dev);
852 unsigned long long size;
855 size = dev_dax_size(dev_dax);
858 return sprintf(buf, "%llu\n", size);
861 static bool alloc_is_aligned(struct dev_dax *dev_dax, resource_size_t size)
864 * The minimum mapping granularity for a device instance is a
865 * single subsection, unless the arch says otherwise.
867 return IS_ALIGNED(size, max_t(unsigned long, dev_dax->align, memremap_compat_align()));
870 static int dev_dax_shrink(struct dev_dax *dev_dax, resource_size_t size)
872 resource_size_t to_shrink = dev_dax_size(dev_dax) - size;
873 struct dax_region *dax_region = dev_dax->region;
874 struct device *dev = &dev_dax->dev;
877 for (i = dev_dax->nr_range - 1; i >= 0; i--) {
878 struct range *range = &dev_dax->ranges[i].range;
879 struct dax_mapping *mapping = dev_dax->ranges[i].mapping;
880 struct resource *adjust = NULL, *res;
881 resource_size_t shrink;
883 shrink = min_t(u64, to_shrink, range_len(range));
884 if (shrink >= range_len(range)) {
885 devm_release_action(dax_region->dev,
886 unregister_dax_mapping, &mapping->dev);
887 trim_dev_dax_range(dev_dax);
894 for_each_dax_region_resource(dax_region, res)
895 if (strcmp(res->name, dev_name(dev)) == 0
896 && res->start == range->start) {
901 if (dev_WARN_ONCE(dev, !adjust || i != dev_dax->nr_range - 1,
902 "failed to find matching resource\n"))
904 return adjust_dev_dax_range(dev_dax, adjust, range_len(range)
911 * Only allow adjustments that preserve the relative pgoff of existing
912 * allocations. I.e. the dev_dax->ranges array is ordered by increasing pgoff.
914 static bool adjust_ok(struct dev_dax *dev_dax, struct resource *res)
916 struct dev_dax_range *last;
919 if (dev_dax->nr_range == 0)
921 if (strcmp(res->name, dev_name(&dev_dax->dev)) != 0)
923 last = &dev_dax->ranges[dev_dax->nr_range - 1];
924 if (last->range.start != res->start || last->range.end != res->end)
926 for (i = 0; i < dev_dax->nr_range - 1; i++) {
927 struct dev_dax_range *dax_range = &dev_dax->ranges[i];
929 if (dax_range->pgoff > last->pgoff)
936 static ssize_t dev_dax_resize(struct dax_region *dax_region,
937 struct dev_dax *dev_dax, resource_size_t size)
939 resource_size_t avail = dax_region_avail_size(dax_region), to_alloc;
940 resource_size_t dev_size = dev_dax_size(dev_dax);
941 struct resource *region_res = &dax_region->res;
942 struct device *dev = &dev_dax->dev;
943 struct resource *res, *first;
944 resource_size_t alloc = 0;
949 if (size == dev_size)
951 if (size > dev_size && size - dev_size > avail)
954 return dev_dax_shrink(dev_dax, size);
956 to_alloc = size - dev_size;
957 if (dev_WARN_ONCE(dev, !alloc_is_aligned(dev_dax, to_alloc),
958 "resize of %pa misaligned\n", &to_alloc))
962 * Expand the device into the unused portion of the region. This
963 * may involve adjusting the end of an existing resource, or
964 * allocating a new resource.
967 first = region_res->child;
969 return alloc_dev_dax_range(dev_dax, dax_region->res.start, to_alloc);
972 for (res = first; res; res = res->sibling) {
973 struct resource *next = res->sibling;
975 /* space at the beginning of the region */
976 if (res == first && res->start > dax_region->res.start) {
977 alloc = min(res->start - dax_region->res.start, to_alloc);
978 rc = alloc_dev_dax_range(dev_dax, dax_region->res.start, alloc);
983 /* space between allocations */
984 if (next && next->start > res->end + 1)
985 alloc = min(next->start - (res->end + 1), to_alloc);
987 /* space at the end of the region */
988 if (!alloc && !next && res->end < region_res->end)
989 alloc = min(region_res->end - res->end, to_alloc);
994 if (adjust_ok(dev_dax, res)) {
995 rc = adjust_dev_dax_range(dev_dax, res, resource_size(res) + alloc);
998 rc = alloc_dev_dax_range(dev_dax, res->end + 1, alloc);
1009 static ssize_t size_store(struct device *dev, struct device_attribute *attr,
1010 const char *buf, size_t len)
1013 unsigned long long val;
1014 struct dev_dax *dev_dax = to_dev_dax(dev);
1015 struct dax_region *dax_region = dev_dax->region;
1017 rc = kstrtoull(buf, 0, &val);
1021 if (!alloc_is_aligned(dev_dax, val)) {
1022 dev_dbg(dev, "%s: size: %lld misaligned\n", __func__, val);
1026 device_lock(dax_region->dev);
1027 if (!dax_region->dev->driver) {
1028 device_unlock(dax_region->dev);
1032 rc = dev_dax_resize(dax_region, dev_dax, val);
1034 device_unlock(dax_region->dev);
1036 return rc == 0 ? len : rc;
1038 static DEVICE_ATTR_RW(size);
1040 static ssize_t range_parse(const char *opt, size_t len, struct range *range)
1042 unsigned long long addr = 0;
1043 char *start, *end, *str;
1044 ssize_t rc = -EINVAL;
1046 str = kstrdup(opt, GFP_KERNEL);
1051 start = strsep(&end, "-");
1055 rc = kstrtoull(start, 16, &addr);
1058 range->start = addr;
1060 rc = kstrtoull(end, 16, &addr);
1070 static ssize_t mapping_store(struct device *dev, struct device_attribute *attr,
1071 const char *buf, size_t len)
1073 struct dev_dax *dev_dax = to_dev_dax(dev);
1074 struct dax_region *dax_region = dev_dax->region;
1079 rc = range_parse(buf, len, &r);
1084 device_lock(dax_region->dev);
1085 if (!dax_region->dev->driver) {
1086 device_unlock(dax_region->dev);
1091 to_alloc = range_len(&r);
1092 if (alloc_is_aligned(dev_dax, to_alloc))
1093 rc = alloc_dev_dax_range(dev_dax, r.start, to_alloc);
1095 device_unlock(dax_region->dev);
1097 return rc == 0 ? len : rc;
1099 static DEVICE_ATTR_WO(mapping);
1101 static ssize_t align_show(struct device *dev,
1102 struct device_attribute *attr, char *buf)
1104 struct dev_dax *dev_dax = to_dev_dax(dev);
1106 return sprintf(buf, "%d\n", dev_dax->align);
1109 static ssize_t dev_dax_validate_align(struct dev_dax *dev_dax)
1111 struct device *dev = &dev_dax->dev;
1114 for (i = 0; i < dev_dax->nr_range; i++) {
1115 size_t len = range_len(&dev_dax->ranges[i].range);
1117 if (!alloc_is_aligned(dev_dax, len)) {
1118 dev_dbg(dev, "%s: align %u invalid for range %d\n",
1119 __func__, dev_dax->align, i);
1127 static ssize_t align_store(struct device *dev, struct device_attribute *attr,
1128 const char *buf, size_t len)
1130 struct dev_dax *dev_dax = to_dev_dax(dev);
1131 struct dax_region *dax_region = dev_dax->region;
1132 unsigned long val, align_save;
1135 rc = kstrtoul(buf, 0, &val);
1139 if (!dax_align_valid(val))
1142 device_lock(dax_region->dev);
1143 if (!dax_region->dev->driver) {
1144 device_unlock(dax_region->dev);
1154 align_save = dev_dax->align;
1155 dev_dax->align = val;
1156 rc = dev_dax_validate_align(dev_dax);
1158 dev_dax->align = align_save;
1161 device_unlock(dax_region->dev);
1162 return rc == 0 ? len : rc;
1164 static DEVICE_ATTR_RW(align);
1166 static int dev_dax_target_node(struct dev_dax *dev_dax)
1168 struct dax_region *dax_region = dev_dax->region;
1170 return dax_region->target_node;
1173 static ssize_t target_node_show(struct device *dev,
1174 struct device_attribute *attr, char *buf)
1176 struct dev_dax *dev_dax = to_dev_dax(dev);
1178 return sprintf(buf, "%d\n", dev_dax_target_node(dev_dax));
1180 static DEVICE_ATTR_RO(target_node);
1182 static ssize_t resource_show(struct device *dev,
1183 struct device_attribute *attr, char *buf)
1185 struct dev_dax *dev_dax = to_dev_dax(dev);
1186 struct dax_region *dax_region = dev_dax->region;
1187 unsigned long long start;
1189 if (dev_dax->nr_range < 1)
1190 start = dax_region->res.start;
1192 start = dev_dax->ranges[0].range.start;
1194 return sprintf(buf, "%#llx\n", start);
1196 static DEVICE_ATTR(resource, 0400, resource_show, NULL);
1198 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
1202 * We only ever expect to handle device-dax instances, i.e. the
1203 * @type argument to MODULE_ALIAS_DAX_DEVICE() is always zero
1205 return sprintf(buf, DAX_DEVICE_MODALIAS_FMT "\n", 0);
1207 static DEVICE_ATTR_RO(modalias);
1209 static ssize_t numa_node_show(struct device *dev,
1210 struct device_attribute *attr, char *buf)
1212 return sprintf(buf, "%d\n", dev_to_node(dev));
1214 static DEVICE_ATTR_RO(numa_node);
1216 static umode_t dev_dax_visible(struct kobject *kobj, struct attribute *a, int n)
1218 struct device *dev = container_of(kobj, struct device, kobj);
1219 struct dev_dax *dev_dax = to_dev_dax(dev);
1220 struct dax_region *dax_region = dev_dax->region;
1222 if (a == &dev_attr_target_node.attr && dev_dax_target_node(dev_dax) < 0)
1224 if (a == &dev_attr_numa_node.attr && !IS_ENABLED(CONFIG_NUMA))
1226 if (a == &dev_attr_mapping.attr && is_static(dax_region))
1228 if ((a == &dev_attr_align.attr ||
1229 a == &dev_attr_size.attr) && is_static(dax_region))
1234 static struct attribute *dev_dax_attributes[] = {
1235 &dev_attr_modalias.attr,
1236 &dev_attr_size.attr,
1237 &dev_attr_mapping.attr,
1238 &dev_attr_target_node.attr,
1239 &dev_attr_align.attr,
1240 &dev_attr_resource.attr,
1241 &dev_attr_numa_node.attr,
1245 static const struct attribute_group dev_dax_attribute_group = {
1246 .attrs = dev_dax_attributes,
1247 .is_visible = dev_dax_visible,
1250 static const struct attribute_group *dax_attribute_groups[] = {
1251 &dev_dax_attribute_group,
1255 static void dev_dax_release(struct device *dev)
1257 struct dev_dax *dev_dax = to_dev_dax(dev);
1258 struct dax_region *dax_region = dev_dax->region;
1259 struct dax_device *dax_dev = dev_dax->dax_dev;
1262 free_dev_dax_id(dev_dax);
1263 dax_region_put(dax_region);
1264 kfree(dev_dax->pgmap);
1268 static const struct device_type dev_dax_type = {
1269 .release = dev_dax_release,
1270 .groups = dax_attribute_groups,
1273 struct dev_dax *devm_create_dev_dax(struct dev_dax_data *data)
1275 struct dax_region *dax_region = data->dax_region;
1276 struct device *parent = dax_region->dev;
1277 struct dax_device *dax_dev;
1278 struct dev_dax *dev_dax;
1279 struct inode *inode;
1283 dev_dax = kzalloc(sizeof(*dev_dax), GFP_KERNEL);
1285 return ERR_PTR(-ENOMEM);
1287 if (is_static(dax_region)) {
1288 if (dev_WARN_ONCE(parent, data->id < 0,
1289 "dynamic id specified to static region\n")) {
1294 dev_dax->id = data->id;
1296 if (dev_WARN_ONCE(parent, data->id >= 0,
1297 "static id specified to dynamic region\n")) {
1302 rc = ida_alloc(&dax_region->ida, GFP_KERNEL);
1308 dev_dax->region = dax_region;
1309 dev = &dev_dax->dev;
1310 device_initialize(dev);
1311 dev_set_name(dev, "dax%d.%d", dax_region->id, dev_dax->id);
1313 rc = alloc_dev_dax_range(dev_dax, dax_region->res.start, data->size);
1318 dev_WARN_ONCE(parent, !is_static(dax_region),
1319 "custom dev_pagemap requires a static dax_region\n");
1321 dev_dax->pgmap = kmemdup(data->pgmap,
1322 sizeof(struct dev_pagemap), GFP_KERNEL);
1323 if (!dev_dax->pgmap) {
1330 * No 'host' or dax_operations since there is no access to this
1331 * device outside of mmap of the resulting character device.
1333 dax_dev = alloc_dax(dev_dax, NULL, NULL, DAXDEV_F_SYNC);
1334 if (IS_ERR(dax_dev)) {
1335 rc = PTR_ERR(dax_dev);
1339 /* a device_dax instance is dead while the driver is not attached */
1342 dev_dax->dax_dev = dax_dev;
1343 dev_dax->target_node = dax_region->target_node;
1344 dev_dax->align = dax_region->align;
1345 ida_init(&dev_dax->ida);
1346 kref_get(&dax_region->kref);
1348 inode = dax_inode(dax_dev);
1349 dev->devt = inode->i_rdev;
1350 if (data->subsys == DEV_DAX_BUS)
1351 dev->bus = &dax_bus_type;
1353 dev->class = dax_class;
1354 dev->parent = parent;
1355 dev->type = &dev_dax_type;
1357 rc = device_add(dev);
1359 kill_dev_dax(dev_dax);
1364 rc = devm_add_action_or_reset(dax_region->dev, unregister_dev_dax, dev);
1368 /* register mapping device for the initial allocation range */
1369 if (dev_dax->nr_range && range_len(&dev_dax->ranges[0].range)) {
1370 rc = devm_register_dax_mapping(dev_dax, 0);
1378 kfree(dev_dax->pgmap);
1380 free_dev_dax_ranges(dev_dax);
1382 free_dev_dax_id(dev_dax);
1388 EXPORT_SYMBOL_GPL(devm_create_dev_dax);
1390 static int match_always_count;
1392 int __dax_driver_register(struct dax_device_driver *dax_drv,
1393 struct module *module, const char *mod_name)
1395 struct device_driver *drv = &dax_drv->drv;
1399 * dax_bus_probe() calls dax_drv->probe() unconditionally.
1400 * So better be safe than sorry and ensure it is provided.
1402 if (!dax_drv->probe)
1405 INIT_LIST_HEAD(&dax_drv->ids);
1406 drv->owner = module;
1407 drv->name = mod_name;
1408 drv->mod_name = mod_name;
1409 drv->bus = &dax_bus_type;
1411 /* there can only be one default driver */
1412 mutex_lock(&dax_bus_lock);
1413 match_always_count += dax_drv->match_always;
1414 if (match_always_count > 1) {
1415 match_always_count--;
1419 mutex_unlock(&dax_bus_lock);
1423 rc = driver_register(drv);
1424 if (rc && dax_drv->match_always) {
1425 mutex_lock(&dax_bus_lock);
1426 match_always_count -= dax_drv->match_always;
1427 mutex_unlock(&dax_bus_lock);
1432 EXPORT_SYMBOL_GPL(__dax_driver_register);
1434 void dax_driver_unregister(struct dax_device_driver *dax_drv)
1436 struct device_driver *drv = &dax_drv->drv;
1437 struct dax_id *dax_id, *_id;
1439 mutex_lock(&dax_bus_lock);
1440 match_always_count -= dax_drv->match_always;
1441 list_for_each_entry_safe(dax_id, _id, &dax_drv->ids, list) {
1442 list_del(&dax_id->list);
1445 mutex_unlock(&dax_bus_lock);
1446 driver_unregister(drv);
1448 EXPORT_SYMBOL_GPL(dax_driver_unregister);
1450 int __init dax_bus_init(void)
1454 if (IS_ENABLED(CONFIG_DEV_DAX_PMEM_COMPAT)) {
1455 dax_class = class_create(THIS_MODULE, "dax");
1456 if (IS_ERR(dax_class))
1457 return PTR_ERR(dax_class);
1460 rc = bus_register(&dax_bus_type);
1462 class_destroy(dax_class);
1466 void __exit dax_bus_exit(void)
1468 bus_unregister(&dax_bus_type);
1469 class_destroy(dax_class);