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 } else if (action == ID_REMOVE) {
95 list_del(&dax_id->list);
98 mutex_unlock(&dax_bus_lock);
102 if (action == ID_ADD)
103 rc = driver_attach(drv);
109 static ssize_t new_id_store(struct device_driver *drv, const char *buf,
112 return do_id_store(drv, buf, count, ID_ADD);
114 static DRIVER_ATTR_WO(new_id);
116 static ssize_t remove_id_store(struct device_driver *drv, const char *buf,
119 return do_id_store(drv, buf, count, ID_REMOVE);
121 static DRIVER_ATTR_WO(remove_id);
123 static struct attribute *dax_drv_attrs[] = {
124 &driver_attr_new_id.attr,
125 &driver_attr_remove_id.attr,
128 ATTRIBUTE_GROUPS(dax_drv);
130 static int dax_bus_match(struct device *dev, struct device_driver *drv);
132 static bool is_static(struct dax_region *dax_region)
134 return (dax_region->res.flags & IORESOURCE_DAX_STATIC) != 0;
137 static u64 dev_dax_size(struct dev_dax *dev_dax)
142 device_lock_assert(&dev_dax->dev);
144 for (i = 0; i < dev_dax->nr_range; i++)
145 size += range_len(&dev_dax->ranges[i].range);
150 static int dax_bus_probe(struct device *dev)
152 struct dax_device_driver *dax_drv = to_dax_drv(dev->driver);
153 struct dev_dax *dev_dax = to_dev_dax(dev);
154 struct dax_region *dax_region = dev_dax->region;
157 if (dev_dax_size(dev_dax) == 0 || dev_dax->id < 0)
160 rc = dax_drv->probe(dev_dax);
162 if (rc || is_static(dax_region))
166 * Track new seed creation only after successful probe of the
169 if (dax_region->seed == dev)
170 dax_region->seed = NULL;
175 static int dax_bus_remove(struct device *dev)
177 struct dax_device_driver *dax_drv = to_dax_drv(dev->driver);
178 struct dev_dax *dev_dax = to_dev_dax(dev);
181 dax_drv->remove(dev_dax);
186 static struct bus_type dax_bus_type = {
188 .uevent = dax_bus_uevent,
189 .match = dax_bus_match,
190 .probe = dax_bus_probe,
191 .remove = dax_bus_remove,
192 .drv_groups = dax_drv_groups,
195 static int dax_bus_match(struct device *dev, struct device_driver *drv)
197 struct dax_device_driver *dax_drv = to_dax_drv(drv);
200 * All but the 'device-dax' driver, which has 'match_always'
201 * set, requires an exact id match.
203 if (dax_drv->match_always)
206 return dax_match_id(dax_drv, dev);
210 * Rely on the fact that drvdata is set before the attributes are
211 * registered, and that the attributes are unregistered before drvdata
212 * is cleared to assume that drvdata is always valid.
214 static ssize_t id_show(struct device *dev,
215 struct device_attribute *attr, char *buf)
217 struct dax_region *dax_region = dev_get_drvdata(dev);
219 return sprintf(buf, "%d\n", dax_region->id);
221 static DEVICE_ATTR_RO(id);
223 static ssize_t region_size_show(struct device *dev,
224 struct device_attribute *attr, char *buf)
226 struct dax_region *dax_region = dev_get_drvdata(dev);
228 return sprintf(buf, "%llu\n", (unsigned long long)
229 resource_size(&dax_region->res));
231 static struct device_attribute dev_attr_region_size = __ATTR(size, 0444,
232 region_size_show, NULL);
234 static ssize_t region_align_show(struct device *dev,
235 struct device_attribute *attr, char *buf)
237 struct dax_region *dax_region = dev_get_drvdata(dev);
239 return sprintf(buf, "%u\n", dax_region->align);
241 static struct device_attribute dev_attr_region_align =
242 __ATTR(align, 0400, region_align_show, NULL);
244 #define for_each_dax_region_resource(dax_region, res) \
245 for (res = (dax_region)->res.child; res; res = res->sibling)
247 static unsigned long long dax_region_avail_size(struct dax_region *dax_region)
249 resource_size_t size = resource_size(&dax_region->res);
250 struct resource *res;
252 device_lock_assert(dax_region->dev);
254 for_each_dax_region_resource(dax_region, res)
255 size -= resource_size(res);
259 static ssize_t available_size_show(struct device *dev,
260 struct device_attribute *attr, char *buf)
262 struct dax_region *dax_region = dev_get_drvdata(dev);
263 unsigned long long size;
266 size = dax_region_avail_size(dax_region);
269 return sprintf(buf, "%llu\n", size);
271 static DEVICE_ATTR_RO(available_size);
273 static ssize_t seed_show(struct device *dev,
274 struct device_attribute *attr, char *buf)
276 struct dax_region *dax_region = dev_get_drvdata(dev);
280 if (is_static(dax_region))
284 seed = dax_region->seed;
285 rc = sprintf(buf, "%s\n", seed ? dev_name(seed) : "");
290 static DEVICE_ATTR_RO(seed);
292 static ssize_t create_show(struct device *dev,
293 struct device_attribute *attr, char *buf)
295 struct dax_region *dax_region = dev_get_drvdata(dev);
296 struct device *youngest;
299 if (is_static(dax_region))
303 youngest = dax_region->youngest;
304 rc = sprintf(buf, "%s\n", youngest ? dev_name(youngest) : "");
310 static ssize_t create_store(struct device *dev, struct device_attribute *attr,
311 const char *buf, size_t len)
313 struct dax_region *dax_region = dev_get_drvdata(dev);
314 unsigned long long avail;
318 if (is_static(dax_region))
321 rc = kstrtoint(buf, 0, &val);
328 avail = dax_region_avail_size(dax_region);
332 struct dev_dax_data data = {
333 .dax_region = dax_region,
337 struct dev_dax *dev_dax = devm_create_dev_dax(&data);
340 rc = PTR_ERR(dev_dax);
343 * In support of crafting multiple new devices
344 * simultaneously multiple seeds can be created,
345 * but only the first one that has not been
346 * successfully bound is tracked as the region
349 if (!dax_region->seed)
350 dax_region->seed = &dev_dax->dev;
351 dax_region->youngest = &dev_dax->dev;
359 static DEVICE_ATTR_RW(create);
361 void kill_dev_dax(struct dev_dax *dev_dax)
363 struct dax_device *dax_dev = dev_dax->dax_dev;
364 struct inode *inode = dax_inode(dax_dev);
367 unmap_mapping_range(inode->i_mapping, 0, 0, 1);
369 EXPORT_SYMBOL_GPL(kill_dev_dax);
371 static void trim_dev_dax_range(struct dev_dax *dev_dax)
373 int i = dev_dax->nr_range - 1;
374 struct range *range = &dev_dax->ranges[i].range;
375 struct dax_region *dax_region = dev_dax->region;
377 device_lock_assert(dax_region->dev);
378 dev_dbg(&dev_dax->dev, "delete range[%d]: %#llx:%#llx\n", i,
379 (unsigned long long)range->start,
380 (unsigned long long)range->end);
382 __release_region(&dax_region->res, range->start, range_len(range));
383 if (--dev_dax->nr_range == 0) {
384 kfree(dev_dax->ranges);
385 dev_dax->ranges = NULL;
389 static void free_dev_dax_ranges(struct dev_dax *dev_dax)
391 while (dev_dax->nr_range)
392 trim_dev_dax_range(dev_dax);
395 static void unregister_dev_dax(void *dev)
397 struct dev_dax *dev_dax = to_dev_dax(dev);
399 dev_dbg(dev, "%s\n", __func__);
401 kill_dev_dax(dev_dax);
402 free_dev_dax_ranges(dev_dax);
407 /* a return value >= 0 indicates this invocation invalidated the id */
408 static int __free_dev_dax_id(struct dev_dax *dev_dax)
410 struct dax_region *dax_region = dev_dax->region;
411 struct device *dev = &dev_dax->dev;
412 int rc = dev_dax->id;
414 device_lock_assert(dev);
416 if (is_static(dax_region) || dev_dax->id < 0)
418 ida_free(&dax_region->ida, dev_dax->id);
423 static int free_dev_dax_id(struct dev_dax *dev_dax)
425 struct device *dev = &dev_dax->dev;
429 rc = __free_dev_dax_id(dev_dax);
434 static ssize_t delete_store(struct device *dev, struct device_attribute *attr,
435 const char *buf, size_t len)
437 struct dax_region *dax_region = dev_get_drvdata(dev);
438 struct dev_dax *dev_dax;
439 struct device *victim;
443 if (is_static(dax_region))
446 victim = device_find_child_by_name(dax_region->dev, buf);
452 dev_dax = to_dev_dax(victim);
453 if (victim->driver || dev_dax_size(dev_dax))
457 * Invalidate the device so it does not become active
458 * again, but always preserve device-id-0 so that
459 * /sys/bus/dax/ is guaranteed to be populated while any
460 * dax_region is registered.
462 if (dev_dax->id > 0) {
463 do_del = __free_dev_dax_id(dev_dax) >= 0;
465 if (dax_region->seed == victim)
466 dax_region->seed = NULL;
467 if (dax_region->youngest == victim)
468 dax_region->youngest = NULL;
472 device_unlock(victim);
474 /* won the race to invalidate the device, clean it up */
476 devm_release_action(dev, unregister_dev_dax, victim);
482 static DEVICE_ATTR_WO(delete);
484 static umode_t dax_region_visible(struct kobject *kobj, struct attribute *a,
487 struct device *dev = container_of(kobj, struct device, kobj);
488 struct dax_region *dax_region = dev_get_drvdata(dev);
490 if (is_static(dax_region))
491 if (a == &dev_attr_available_size.attr
492 || a == &dev_attr_create.attr
493 || a == &dev_attr_seed.attr
494 || a == &dev_attr_delete.attr)
499 static struct attribute *dax_region_attributes[] = {
500 &dev_attr_available_size.attr,
501 &dev_attr_region_size.attr,
502 &dev_attr_region_align.attr,
503 &dev_attr_create.attr,
505 &dev_attr_delete.attr,
510 static const struct attribute_group dax_region_attribute_group = {
511 .name = "dax_region",
512 .attrs = dax_region_attributes,
513 .is_visible = dax_region_visible,
516 static const struct attribute_group *dax_region_attribute_groups[] = {
517 &dax_region_attribute_group,
521 static void dax_region_free(struct kref *kref)
523 struct dax_region *dax_region;
525 dax_region = container_of(kref, struct dax_region, kref);
529 void dax_region_put(struct dax_region *dax_region)
531 kref_put(&dax_region->kref, dax_region_free);
533 EXPORT_SYMBOL_GPL(dax_region_put);
535 static void dax_region_unregister(void *region)
537 struct dax_region *dax_region = region;
539 sysfs_remove_groups(&dax_region->dev->kobj,
540 dax_region_attribute_groups);
541 dax_region_put(dax_region);
544 struct dax_region *alloc_dax_region(struct device *parent, int region_id,
545 struct range *range, int target_node, unsigned int align,
548 struct dax_region *dax_region;
551 * The DAX core assumes that it can store its private data in
552 * parent->driver_data. This WARN is a reminder / safeguard for
553 * developers of device-dax drivers.
555 if (dev_get_drvdata(parent)) {
556 dev_WARN(parent, "dax core failed to setup private data\n");
560 if (!IS_ALIGNED(range->start, align)
561 || !IS_ALIGNED(range_len(range), align))
564 dax_region = kzalloc(sizeof(*dax_region), GFP_KERNEL);
568 dev_set_drvdata(parent, dax_region);
569 kref_init(&dax_region->kref);
570 dax_region->id = region_id;
571 dax_region->align = align;
572 dax_region->dev = parent;
573 dax_region->target_node = target_node;
574 ida_init(&dax_region->ida);
575 dax_region->res = (struct resource) {
576 .start = range->start,
578 .flags = IORESOURCE_MEM | flags,
581 if (sysfs_create_groups(&parent->kobj, dax_region_attribute_groups)) {
586 kref_get(&dax_region->kref);
587 if (devm_add_action_or_reset(parent, dax_region_unregister, dax_region))
591 EXPORT_SYMBOL_GPL(alloc_dax_region);
593 static void dax_mapping_release(struct device *dev)
595 struct dax_mapping *mapping = to_dax_mapping(dev);
596 struct dev_dax *dev_dax = to_dev_dax(dev->parent);
598 ida_free(&dev_dax->ida, mapping->id);
602 static void unregister_dax_mapping(void *data)
604 struct device *dev = data;
605 struct dax_mapping *mapping = to_dax_mapping(dev);
606 struct dev_dax *dev_dax = to_dev_dax(dev->parent);
607 struct dax_region *dax_region = dev_dax->region;
609 dev_dbg(dev, "%s\n", __func__);
611 device_lock_assert(dax_region->dev);
613 dev_dax->ranges[mapping->range_id].mapping = NULL;
614 mapping->range_id = -1;
620 static struct dev_dax_range *get_dax_range(struct device *dev)
622 struct dax_mapping *mapping = to_dax_mapping(dev);
623 struct dev_dax *dev_dax = to_dev_dax(dev->parent);
624 struct dax_region *dax_region = dev_dax->region;
626 device_lock(dax_region->dev);
627 if (mapping->range_id < 0) {
628 device_unlock(dax_region->dev);
632 return &dev_dax->ranges[mapping->range_id];
635 static void put_dax_range(struct dev_dax_range *dax_range)
637 struct dax_mapping *mapping = dax_range->mapping;
638 struct dev_dax *dev_dax = to_dev_dax(mapping->dev.parent);
639 struct dax_region *dax_region = dev_dax->region;
641 device_unlock(dax_region->dev);
644 static ssize_t start_show(struct device *dev,
645 struct device_attribute *attr, char *buf)
647 struct dev_dax_range *dax_range;
650 dax_range = get_dax_range(dev);
653 rc = sprintf(buf, "%#llx\n", dax_range->range.start);
654 put_dax_range(dax_range);
658 static DEVICE_ATTR(start, 0400, start_show, NULL);
660 static ssize_t end_show(struct device *dev,
661 struct device_attribute *attr, char *buf)
663 struct dev_dax_range *dax_range;
666 dax_range = get_dax_range(dev);
669 rc = sprintf(buf, "%#llx\n", dax_range->range.end);
670 put_dax_range(dax_range);
674 static DEVICE_ATTR(end, 0400, end_show, NULL);
676 static ssize_t pgoff_show(struct device *dev,
677 struct device_attribute *attr, char *buf)
679 struct dev_dax_range *dax_range;
682 dax_range = get_dax_range(dev);
685 rc = sprintf(buf, "%#lx\n", dax_range->pgoff);
686 put_dax_range(dax_range);
690 static DEVICE_ATTR(page_offset, 0400, pgoff_show, NULL);
692 static struct attribute *dax_mapping_attributes[] = {
693 &dev_attr_start.attr,
695 &dev_attr_page_offset.attr,
699 static const struct attribute_group dax_mapping_attribute_group = {
700 .attrs = dax_mapping_attributes,
703 static const struct attribute_group *dax_mapping_attribute_groups[] = {
704 &dax_mapping_attribute_group,
708 static struct device_type dax_mapping_type = {
709 .release = dax_mapping_release,
710 .groups = dax_mapping_attribute_groups,
713 static int devm_register_dax_mapping(struct dev_dax *dev_dax, int range_id)
715 struct dax_region *dax_region = dev_dax->region;
716 struct dax_mapping *mapping;
720 device_lock_assert(dax_region->dev);
722 if (dev_WARN_ONCE(&dev_dax->dev, !dax_region->dev->driver,
723 "region disabled\n"))
726 mapping = kzalloc(sizeof(*mapping), GFP_KERNEL);
729 mapping->range_id = range_id;
730 mapping->id = ida_alloc(&dev_dax->ida, GFP_KERNEL);
731 if (mapping->id < 0) {
735 dev_dax->ranges[range_id].mapping = mapping;
737 device_initialize(dev);
738 dev->parent = &dev_dax->dev;
739 dev->type = &dax_mapping_type;
740 dev_set_name(dev, "mapping%d", mapping->id);
741 rc = device_add(dev);
747 rc = devm_add_action_or_reset(dax_region->dev, unregister_dax_mapping,
754 static int alloc_dev_dax_range(struct dev_dax *dev_dax, u64 start,
755 resource_size_t size)
757 struct dax_region *dax_region = dev_dax->region;
758 struct resource *res = &dax_region->res;
759 struct device *dev = &dev_dax->dev;
760 struct dev_dax_range *ranges;
761 unsigned long pgoff = 0;
762 struct resource *alloc;
765 device_lock_assert(dax_region->dev);
767 /* handle the seed alloc special case */
769 if (dev_WARN_ONCE(dev, dev_dax->nr_range,
770 "0-size allocation must be first\n"))
772 /* nr_range == 0 is elsewhere special cased as 0-size device */
776 alloc = __request_region(res, start, size, dev_name(dev), 0);
780 ranges = krealloc(dev_dax->ranges, sizeof(*ranges)
781 * (dev_dax->nr_range + 1), GFP_KERNEL);
783 __release_region(res, alloc->start, resource_size(alloc));
787 for (i = 0; i < dev_dax->nr_range; i++)
788 pgoff += PHYS_PFN(range_len(&ranges[i].range));
789 dev_dax->ranges = ranges;
790 ranges[dev_dax->nr_range++] = (struct dev_dax_range) {
793 .start = alloc->start,
798 dev_dbg(dev, "alloc range[%d]: %pa:%pa\n", dev_dax->nr_range - 1,
799 &alloc->start, &alloc->end);
801 * A dev_dax instance must be registered before mapping device
802 * children can be added. Defer to devm_create_dev_dax() to add
803 * the initial mapping device.
805 if (!device_is_registered(&dev_dax->dev))
808 rc = devm_register_dax_mapping(dev_dax, dev_dax->nr_range - 1);
810 trim_dev_dax_range(dev_dax);
815 static int adjust_dev_dax_range(struct dev_dax *dev_dax, struct resource *res, resource_size_t size)
817 int last_range = dev_dax->nr_range - 1;
818 struct dev_dax_range *dax_range = &dev_dax->ranges[last_range];
819 struct dax_region *dax_region = dev_dax->region;
820 bool is_shrink = resource_size(res) > size;
821 struct range *range = &dax_range->range;
822 struct device *dev = &dev_dax->dev;
825 device_lock_assert(dax_region->dev);
827 if (dev_WARN_ONCE(dev, !size, "deletion is handled by dev_dax_shrink\n"))
830 rc = adjust_resource(res, range->start, size);
834 *range = (struct range) {
835 .start = range->start,
836 .end = range->start + size - 1,
839 dev_dbg(dev, "%s range[%d]: %#llx:%#llx\n", is_shrink ? "shrink" : "extend",
840 last_range, (unsigned long long) range->start,
841 (unsigned long long) range->end);
846 static ssize_t size_show(struct device *dev,
847 struct device_attribute *attr, char *buf)
849 struct dev_dax *dev_dax = to_dev_dax(dev);
850 unsigned long long size;
853 size = dev_dax_size(dev_dax);
856 return sprintf(buf, "%llu\n", size);
859 static bool alloc_is_aligned(struct dev_dax *dev_dax, resource_size_t size)
862 * The minimum mapping granularity for a device instance is a
863 * single subsection, unless the arch says otherwise.
865 return IS_ALIGNED(size, max_t(unsigned long, dev_dax->align, memremap_compat_align()));
868 static int dev_dax_shrink(struct dev_dax *dev_dax, resource_size_t size)
870 resource_size_t to_shrink = dev_dax_size(dev_dax) - size;
871 struct dax_region *dax_region = dev_dax->region;
872 struct device *dev = &dev_dax->dev;
875 for (i = dev_dax->nr_range - 1; i >= 0; i--) {
876 struct range *range = &dev_dax->ranges[i].range;
877 struct dax_mapping *mapping = dev_dax->ranges[i].mapping;
878 struct resource *adjust = NULL, *res;
879 resource_size_t shrink;
881 shrink = min_t(u64, to_shrink, range_len(range));
882 if (shrink >= range_len(range)) {
883 devm_release_action(dax_region->dev,
884 unregister_dax_mapping, &mapping->dev);
885 trim_dev_dax_range(dev_dax);
892 for_each_dax_region_resource(dax_region, res)
893 if (strcmp(res->name, dev_name(dev)) == 0
894 && res->start == range->start) {
899 if (dev_WARN_ONCE(dev, !adjust || i != dev_dax->nr_range - 1,
900 "failed to find matching resource\n"))
902 return adjust_dev_dax_range(dev_dax, adjust, range_len(range)
909 * Only allow adjustments that preserve the relative pgoff of existing
910 * allocations. I.e. the dev_dax->ranges array is ordered by increasing pgoff.
912 static bool adjust_ok(struct dev_dax *dev_dax, struct resource *res)
914 struct dev_dax_range *last;
917 if (dev_dax->nr_range == 0)
919 if (strcmp(res->name, dev_name(&dev_dax->dev)) != 0)
921 last = &dev_dax->ranges[dev_dax->nr_range - 1];
922 if (last->range.start != res->start || last->range.end != res->end)
924 for (i = 0; i < dev_dax->nr_range - 1; i++) {
925 struct dev_dax_range *dax_range = &dev_dax->ranges[i];
927 if (dax_range->pgoff > last->pgoff)
934 static ssize_t dev_dax_resize(struct dax_region *dax_region,
935 struct dev_dax *dev_dax, resource_size_t size)
937 resource_size_t avail = dax_region_avail_size(dax_region), to_alloc;
938 resource_size_t dev_size = dev_dax_size(dev_dax);
939 struct resource *region_res = &dax_region->res;
940 struct device *dev = &dev_dax->dev;
941 struct resource *res, *first;
942 resource_size_t alloc = 0;
947 if (size == dev_size)
949 if (size > dev_size && size - dev_size > avail)
952 return dev_dax_shrink(dev_dax, size);
954 to_alloc = size - dev_size;
955 if (dev_WARN_ONCE(dev, !alloc_is_aligned(dev_dax, to_alloc),
956 "resize of %pa misaligned\n", &to_alloc))
960 * Expand the device into the unused portion of the region. This
961 * may involve adjusting the end of an existing resource, or
962 * allocating a new resource.
965 first = region_res->child;
967 return alloc_dev_dax_range(dev_dax, dax_region->res.start, to_alloc);
970 for (res = first; res; res = res->sibling) {
971 struct resource *next = res->sibling;
973 /* space at the beginning of the region */
974 if (res == first && res->start > dax_region->res.start) {
975 alloc = min(res->start - dax_region->res.start, to_alloc);
976 rc = alloc_dev_dax_range(dev_dax, dax_region->res.start, alloc);
981 /* space between allocations */
982 if (next && next->start > res->end + 1)
983 alloc = min(next->start - (res->end + 1), to_alloc);
985 /* space at the end of the region */
986 if (!alloc && !next && res->end < region_res->end)
987 alloc = min(region_res->end - res->end, to_alloc);
992 if (adjust_ok(dev_dax, res)) {
993 rc = adjust_dev_dax_range(dev_dax, res, resource_size(res) + alloc);
996 rc = alloc_dev_dax_range(dev_dax, res->end + 1, alloc);
1007 static ssize_t size_store(struct device *dev, struct device_attribute *attr,
1008 const char *buf, size_t len)
1011 unsigned long long val;
1012 struct dev_dax *dev_dax = to_dev_dax(dev);
1013 struct dax_region *dax_region = dev_dax->region;
1015 rc = kstrtoull(buf, 0, &val);
1019 if (!alloc_is_aligned(dev_dax, val)) {
1020 dev_dbg(dev, "%s: size: %lld misaligned\n", __func__, val);
1024 device_lock(dax_region->dev);
1025 if (!dax_region->dev->driver) {
1026 device_unlock(dax_region->dev);
1030 rc = dev_dax_resize(dax_region, dev_dax, val);
1032 device_unlock(dax_region->dev);
1034 return rc == 0 ? len : rc;
1036 static DEVICE_ATTR_RW(size);
1038 static ssize_t range_parse(const char *opt, size_t len, struct range *range)
1040 unsigned long long addr = 0;
1041 char *start, *end, *str;
1042 ssize_t rc = -EINVAL;
1044 str = kstrdup(opt, GFP_KERNEL);
1049 start = strsep(&end, "-");
1053 rc = kstrtoull(start, 16, &addr);
1056 range->start = addr;
1058 rc = kstrtoull(end, 16, &addr);
1068 static ssize_t mapping_store(struct device *dev, struct device_attribute *attr,
1069 const char *buf, size_t len)
1071 struct dev_dax *dev_dax = to_dev_dax(dev);
1072 struct dax_region *dax_region = dev_dax->region;
1077 rc = range_parse(buf, len, &r);
1082 device_lock(dax_region->dev);
1083 if (!dax_region->dev->driver) {
1084 device_unlock(dax_region->dev);
1089 to_alloc = range_len(&r);
1090 if (alloc_is_aligned(dev_dax, to_alloc))
1091 rc = alloc_dev_dax_range(dev_dax, r.start, to_alloc);
1093 device_unlock(dax_region->dev);
1095 return rc == 0 ? len : rc;
1097 static DEVICE_ATTR_WO(mapping);
1099 static ssize_t align_show(struct device *dev,
1100 struct device_attribute *attr, char *buf)
1102 struct dev_dax *dev_dax = to_dev_dax(dev);
1104 return sprintf(buf, "%d\n", dev_dax->align);
1107 static ssize_t dev_dax_validate_align(struct dev_dax *dev_dax)
1109 struct device *dev = &dev_dax->dev;
1112 for (i = 0; i < dev_dax->nr_range; i++) {
1113 size_t len = range_len(&dev_dax->ranges[i].range);
1115 if (!alloc_is_aligned(dev_dax, len)) {
1116 dev_dbg(dev, "%s: align %u invalid for range %d\n",
1117 __func__, dev_dax->align, i);
1125 static ssize_t align_store(struct device *dev, struct device_attribute *attr,
1126 const char *buf, size_t len)
1128 struct dev_dax *dev_dax = to_dev_dax(dev);
1129 struct dax_region *dax_region = dev_dax->region;
1130 unsigned long val, align_save;
1133 rc = kstrtoul(buf, 0, &val);
1137 if (!dax_align_valid(val))
1140 device_lock(dax_region->dev);
1141 if (!dax_region->dev->driver) {
1142 device_unlock(dax_region->dev);
1152 align_save = dev_dax->align;
1153 dev_dax->align = val;
1154 rc = dev_dax_validate_align(dev_dax);
1156 dev_dax->align = align_save;
1159 device_unlock(dax_region->dev);
1160 return rc == 0 ? len : rc;
1162 static DEVICE_ATTR_RW(align);
1164 static int dev_dax_target_node(struct dev_dax *dev_dax)
1166 struct dax_region *dax_region = dev_dax->region;
1168 return dax_region->target_node;
1171 static ssize_t target_node_show(struct device *dev,
1172 struct device_attribute *attr, char *buf)
1174 struct dev_dax *dev_dax = to_dev_dax(dev);
1176 return sprintf(buf, "%d\n", dev_dax_target_node(dev_dax));
1178 static DEVICE_ATTR_RO(target_node);
1180 static ssize_t resource_show(struct device *dev,
1181 struct device_attribute *attr, char *buf)
1183 struct dev_dax *dev_dax = to_dev_dax(dev);
1184 struct dax_region *dax_region = dev_dax->region;
1185 unsigned long long start;
1187 if (dev_dax->nr_range < 1)
1188 start = dax_region->res.start;
1190 start = dev_dax->ranges[0].range.start;
1192 return sprintf(buf, "%#llx\n", start);
1194 static DEVICE_ATTR(resource, 0400, resource_show, NULL);
1196 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
1200 * We only ever expect to handle device-dax instances, i.e. the
1201 * @type argument to MODULE_ALIAS_DAX_DEVICE() is always zero
1203 return sprintf(buf, DAX_DEVICE_MODALIAS_FMT "\n", 0);
1205 static DEVICE_ATTR_RO(modalias);
1207 static ssize_t numa_node_show(struct device *dev,
1208 struct device_attribute *attr, char *buf)
1210 return sprintf(buf, "%d\n", dev_to_node(dev));
1212 static DEVICE_ATTR_RO(numa_node);
1214 static umode_t dev_dax_visible(struct kobject *kobj, struct attribute *a, int n)
1216 struct device *dev = container_of(kobj, struct device, kobj);
1217 struct dev_dax *dev_dax = to_dev_dax(dev);
1218 struct dax_region *dax_region = dev_dax->region;
1220 if (a == &dev_attr_target_node.attr && dev_dax_target_node(dev_dax) < 0)
1222 if (a == &dev_attr_numa_node.attr && !IS_ENABLED(CONFIG_NUMA))
1224 if (a == &dev_attr_mapping.attr && is_static(dax_region))
1226 if ((a == &dev_attr_align.attr ||
1227 a == &dev_attr_size.attr) && is_static(dax_region))
1232 static struct attribute *dev_dax_attributes[] = {
1233 &dev_attr_modalias.attr,
1234 &dev_attr_size.attr,
1235 &dev_attr_mapping.attr,
1236 &dev_attr_target_node.attr,
1237 &dev_attr_align.attr,
1238 &dev_attr_resource.attr,
1239 &dev_attr_numa_node.attr,
1243 static const struct attribute_group dev_dax_attribute_group = {
1244 .attrs = dev_dax_attributes,
1245 .is_visible = dev_dax_visible,
1248 static const struct attribute_group *dax_attribute_groups[] = {
1249 &dev_dax_attribute_group,
1253 static void dev_dax_release(struct device *dev)
1255 struct dev_dax *dev_dax = to_dev_dax(dev);
1256 struct dax_region *dax_region = dev_dax->region;
1257 struct dax_device *dax_dev = dev_dax->dax_dev;
1260 free_dev_dax_id(dev_dax);
1261 dax_region_put(dax_region);
1262 kfree(dev_dax->pgmap);
1266 static const struct device_type dev_dax_type = {
1267 .release = dev_dax_release,
1268 .groups = dax_attribute_groups,
1271 struct dev_dax *devm_create_dev_dax(struct dev_dax_data *data)
1273 struct dax_region *dax_region = data->dax_region;
1274 struct device *parent = dax_region->dev;
1275 struct dax_device *dax_dev;
1276 struct dev_dax *dev_dax;
1277 struct inode *inode;
1281 dev_dax = kzalloc(sizeof(*dev_dax), GFP_KERNEL);
1283 return ERR_PTR(-ENOMEM);
1285 if (is_static(dax_region)) {
1286 if (dev_WARN_ONCE(parent, data->id < 0,
1287 "dynamic id specified to static region\n")) {
1292 dev_dax->id = data->id;
1294 if (dev_WARN_ONCE(parent, data->id >= 0,
1295 "static id specified to dynamic region\n")) {
1300 rc = ida_alloc(&dax_region->ida, GFP_KERNEL);
1306 dev_dax->region = dax_region;
1307 dev = &dev_dax->dev;
1308 device_initialize(dev);
1309 dev_set_name(dev, "dax%d.%d", dax_region->id, dev_dax->id);
1311 rc = alloc_dev_dax_range(dev_dax, dax_region->res.start, data->size);
1316 dev_WARN_ONCE(parent, !is_static(dax_region),
1317 "custom dev_pagemap requires a static dax_region\n");
1319 dev_dax->pgmap = kmemdup(data->pgmap,
1320 sizeof(struct dev_pagemap), GFP_KERNEL);
1321 if (!dev_dax->pgmap) {
1328 * No 'host' or dax_operations since there is no access to this
1329 * device outside of mmap of the resulting character device.
1331 dax_dev = alloc_dax(dev_dax, NULL, NULL, DAXDEV_F_SYNC);
1332 if (IS_ERR(dax_dev)) {
1333 rc = PTR_ERR(dax_dev);
1337 /* a device_dax instance is dead while the driver is not attached */
1340 dev_dax->dax_dev = dax_dev;
1341 dev_dax->target_node = dax_region->target_node;
1342 dev_dax->align = dax_region->align;
1343 ida_init(&dev_dax->ida);
1344 kref_get(&dax_region->kref);
1346 inode = dax_inode(dax_dev);
1347 dev->devt = inode->i_rdev;
1348 if (data->subsys == DEV_DAX_BUS)
1349 dev->bus = &dax_bus_type;
1351 dev->class = dax_class;
1352 dev->parent = parent;
1353 dev->type = &dev_dax_type;
1355 rc = device_add(dev);
1357 kill_dev_dax(dev_dax);
1362 rc = devm_add_action_or_reset(dax_region->dev, unregister_dev_dax, dev);
1366 /* register mapping device for the initial allocation range */
1367 if (dev_dax->nr_range && range_len(&dev_dax->ranges[0].range)) {
1368 rc = devm_register_dax_mapping(dev_dax, 0);
1376 kfree(dev_dax->pgmap);
1378 free_dev_dax_ranges(dev_dax);
1380 free_dev_dax_id(dev_dax);
1386 EXPORT_SYMBOL_GPL(devm_create_dev_dax);
1388 static int match_always_count;
1390 int __dax_driver_register(struct dax_device_driver *dax_drv,
1391 struct module *module, const char *mod_name)
1393 struct device_driver *drv = &dax_drv->drv;
1397 * dax_bus_probe() calls dax_drv->probe() unconditionally.
1398 * So better be safe than sorry and ensure it is provided.
1400 if (!dax_drv->probe)
1403 INIT_LIST_HEAD(&dax_drv->ids);
1404 drv->owner = module;
1405 drv->name = mod_name;
1406 drv->mod_name = mod_name;
1407 drv->bus = &dax_bus_type;
1409 /* there can only be one default driver */
1410 mutex_lock(&dax_bus_lock);
1411 match_always_count += dax_drv->match_always;
1412 if (match_always_count > 1) {
1413 match_always_count--;
1417 mutex_unlock(&dax_bus_lock);
1421 rc = driver_register(drv);
1422 if (rc && dax_drv->match_always) {
1423 mutex_lock(&dax_bus_lock);
1424 match_always_count -= dax_drv->match_always;
1425 mutex_unlock(&dax_bus_lock);
1430 EXPORT_SYMBOL_GPL(__dax_driver_register);
1432 void dax_driver_unregister(struct dax_device_driver *dax_drv)
1434 struct device_driver *drv = &dax_drv->drv;
1435 struct dax_id *dax_id, *_id;
1437 mutex_lock(&dax_bus_lock);
1438 match_always_count -= dax_drv->match_always;
1439 list_for_each_entry_safe(dax_id, _id, &dax_drv->ids, list) {
1440 list_del(&dax_id->list);
1443 mutex_unlock(&dax_bus_lock);
1444 driver_unregister(drv);
1446 EXPORT_SYMBOL_GPL(dax_driver_unregister);
1448 int __init dax_bus_init(void)
1452 if (IS_ENABLED(CONFIG_DEV_DAX_PMEM_COMPAT)) {
1453 dax_class = class_create(THIS_MODULE, "dax");
1454 if (IS_ERR(dax_class))
1455 return PTR_ERR(dax_class);
1458 rc = bus_register(&dax_bus_type);
1460 class_destroy(dax_class);
1464 void __exit dax_bus_exit(void)
1466 bus_unregister(&dax_bus_type);
1467 class_destroy(dax_class);