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>
8 #include <linux/dax.h>
9 #include <linux/io.h>
10 #include "dax-private.h"
11 #include "bus.h"
12 
13 static DEFINE_MUTEX(dax_bus_lock);
14 
15 #define DAX_NAME_LEN 30
16 struct dax_id {
17 	struct list_head list;
18 	char dev_name[DAX_NAME_LEN];
19 };
20 
dax_bus_uevent(struct device * dev,struct kobj_uevent_env * env)21 static int dax_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
22 {
23 	/*
24 	 * We only ever expect to handle device-dax instances, i.e. the
25 	 * @type argument to MODULE_ALIAS_DAX_DEVICE() is always zero
26 	 */
27 	return add_uevent_var(env, "MODALIAS=" DAX_DEVICE_MODALIAS_FMT, 0);
28 }
29 
to_dax_drv(struct device_driver * drv)30 static struct dax_device_driver *to_dax_drv(struct device_driver *drv)
31 {
32 	return container_of(drv, struct dax_device_driver, drv);
33 }
34 
__dax_match_id(struct dax_device_driver * dax_drv,const char * dev_name)35 static struct dax_id *__dax_match_id(struct dax_device_driver *dax_drv,
36 		const char *dev_name)
37 {
38 	struct dax_id *dax_id;
39 
40 	lockdep_assert_held(&dax_bus_lock);
41 
42 	list_for_each_entry(dax_id, &dax_drv->ids, list)
43 		if (sysfs_streq(dax_id->dev_name, dev_name))
44 			return dax_id;
45 	return NULL;
46 }
47 
dax_match_id(struct dax_device_driver * dax_drv,struct device * dev)48 static int dax_match_id(struct dax_device_driver *dax_drv, struct device *dev)
49 {
50 	int match;
51 
52 	mutex_lock(&dax_bus_lock);
53 	match = !!__dax_match_id(dax_drv, dev_name(dev));
54 	mutex_unlock(&dax_bus_lock);
55 
56 	return match;
57 }
58 
59 enum id_action {
60 	ID_REMOVE,
61 	ID_ADD,
62 };
63 
do_id_store(struct device_driver * drv,const char * buf,size_t count,enum id_action action)64 static ssize_t do_id_store(struct device_driver *drv, const char *buf,
65 		size_t count, enum id_action action)
66 {
67 	struct dax_device_driver *dax_drv = to_dax_drv(drv);
68 	unsigned int region_id, id;
69 	char devname[DAX_NAME_LEN];
70 	struct dax_id *dax_id;
71 	ssize_t rc = count;
72 	int fields;
73 
74 	fields = sscanf(buf, "dax%d.%d", &region_id, &id);
75 	if (fields != 2)
76 		return -EINVAL;
77 	sprintf(devname, "dax%d.%d", region_id, id);
78 	if (!sysfs_streq(buf, devname))
79 		return -EINVAL;
80 
81 	mutex_lock(&dax_bus_lock);
82 	dax_id = __dax_match_id(dax_drv, buf);
83 	if (!dax_id) {
84 		if (action == ID_ADD) {
85 			dax_id = kzalloc(sizeof(*dax_id), GFP_KERNEL);
86 			if (dax_id) {
87 				strncpy(dax_id->dev_name, buf, DAX_NAME_LEN);
88 				list_add(&dax_id->list, &dax_drv->ids);
89 			} else
90 				rc = -ENOMEM;
91 		}
92 	} else if (action == ID_REMOVE) {
93 		list_del(&dax_id->list);
94 		kfree(dax_id);
95 	}
96 	mutex_unlock(&dax_bus_lock);
97 
98 	if (rc < 0)
99 		return rc;
100 	if (action == ID_ADD)
101 		rc = driver_attach(drv);
102 	if (rc)
103 		return rc;
104 	return count;
105 }
106 
new_id_store(struct device_driver * drv,const char * buf,size_t count)107 static ssize_t new_id_store(struct device_driver *drv, const char *buf,
108 		size_t count)
109 {
110 	return do_id_store(drv, buf, count, ID_ADD);
111 }
112 static DRIVER_ATTR_WO(new_id);
113 
remove_id_store(struct device_driver * drv,const char * buf,size_t count)114 static ssize_t remove_id_store(struct device_driver *drv, const char *buf,
115 		size_t count)
116 {
117 	return do_id_store(drv, buf, count, ID_REMOVE);
118 }
119 static DRIVER_ATTR_WO(remove_id);
120 
121 static struct attribute *dax_drv_attrs[] = {
122 	&driver_attr_new_id.attr,
123 	&driver_attr_remove_id.attr,
124 	NULL,
125 };
126 ATTRIBUTE_GROUPS(dax_drv);
127 
128 static int dax_bus_match(struct device *dev, struct device_driver *drv);
129 
130 /*
131  * Static dax regions are regions created by an external subsystem
132  * nvdimm where a single range is assigned. Its boundaries are by the external
133  * subsystem and are usually limited to one physical memory range. For example,
134  * for PMEM it is usually defined by NVDIMM Namespace boundaries (i.e. a
135  * single contiguous range)
136  *
137  * On dynamic dax regions, the assigned region can be partitioned by dax core
138  * into multiple subdivisions. A subdivision is represented into one
139  * /dev/daxN.M device composed by one or more potentially discontiguous ranges.
140  *
141  * When allocating a dax region, drivers must set whether it's static
142  * (IORESOURCE_DAX_STATIC).  On static dax devices, the @pgmap is pre-assigned
143  * to dax core when calling devm_create_dev_dax(), whereas in dynamic dax
144  * devices it is NULL but afterwards allocated by dax core on device ->probe().
145  * Care is needed to make sure that dynamic dax devices are torn down with a
146  * cleared @pgmap field (see kill_dev_dax()).
147  */
is_static(struct dax_region * dax_region)148 static bool is_static(struct dax_region *dax_region)
149 {
150 	return (dax_region->res.flags & IORESOURCE_DAX_STATIC) != 0;
151 }
152 
static_dev_dax(struct dev_dax * dev_dax)153 bool static_dev_dax(struct dev_dax *dev_dax)
154 {
155 	return is_static(dev_dax->region);
156 }
157 EXPORT_SYMBOL_GPL(static_dev_dax);
158 
dev_dax_size(struct dev_dax * dev_dax)159 static u64 dev_dax_size(struct dev_dax *dev_dax)
160 {
161 	u64 size = 0;
162 	int i;
163 
164 	device_lock_assert(&dev_dax->dev);
165 
166 	for (i = 0; i < dev_dax->nr_range; i++)
167 		size += range_len(&dev_dax->ranges[i].range);
168 
169 	return size;
170 }
171 
dax_bus_probe(struct device * dev)172 static int dax_bus_probe(struct device *dev)
173 {
174 	struct dax_device_driver *dax_drv = to_dax_drv(dev->driver);
175 	struct dev_dax *dev_dax = to_dev_dax(dev);
176 	struct dax_region *dax_region = dev_dax->region;
177 	int rc;
178 
179 	if (dev_dax_size(dev_dax) == 0 || dev_dax->id < 0)
180 		return -ENXIO;
181 
182 	rc = dax_drv->probe(dev_dax);
183 
184 	if (rc || is_static(dax_region))
185 		return rc;
186 
187 	/*
188 	 * Track new seed creation only after successful probe of the
189 	 * previous seed.
190 	 */
191 	if (dax_region->seed == dev)
192 		dax_region->seed = NULL;
193 
194 	return 0;
195 }
196 
dax_bus_remove(struct device * dev)197 static void dax_bus_remove(struct device *dev)
198 {
199 	struct dax_device_driver *dax_drv = to_dax_drv(dev->driver);
200 	struct dev_dax *dev_dax = to_dev_dax(dev);
201 
202 	if (dax_drv->remove)
203 		dax_drv->remove(dev_dax);
204 }
205 
206 static struct bus_type dax_bus_type = {
207 	.name = "dax",
208 	.uevent = dax_bus_uevent,
209 	.match = dax_bus_match,
210 	.probe = dax_bus_probe,
211 	.remove = dax_bus_remove,
212 	.drv_groups = dax_drv_groups,
213 };
214 
dax_bus_match(struct device * dev,struct device_driver * drv)215 static int dax_bus_match(struct device *dev, struct device_driver *drv)
216 {
217 	struct dax_device_driver *dax_drv = to_dax_drv(drv);
218 
219 	/*
220 	 * All but the 'device-dax' driver, which has 'match_always'
221 	 * set, requires an exact id match.
222 	 */
223 	if (dax_drv->match_always)
224 		return 1;
225 
226 	return dax_match_id(dax_drv, dev);
227 }
228 
229 /*
230  * Rely on the fact that drvdata is set before the attributes are
231  * registered, and that the attributes are unregistered before drvdata
232  * is cleared to assume that drvdata is always valid.
233  */
id_show(struct device * dev,struct device_attribute * attr,char * buf)234 static ssize_t id_show(struct device *dev,
235 		struct device_attribute *attr, char *buf)
236 {
237 	struct dax_region *dax_region = dev_get_drvdata(dev);
238 
239 	return sprintf(buf, "%d\n", dax_region->id);
240 }
241 static DEVICE_ATTR_RO(id);
242 
region_size_show(struct device * dev,struct device_attribute * attr,char * buf)243 static ssize_t region_size_show(struct device *dev,
244 		struct device_attribute *attr, char *buf)
245 {
246 	struct dax_region *dax_region = dev_get_drvdata(dev);
247 
248 	return sprintf(buf, "%llu\n", (unsigned long long)
249 			resource_size(&dax_region->res));
250 }
251 static struct device_attribute dev_attr_region_size = __ATTR(size, 0444,
252 		region_size_show, NULL);
253 
region_align_show(struct device * dev,struct device_attribute * attr,char * buf)254 static ssize_t region_align_show(struct device *dev,
255 		struct device_attribute *attr, char *buf)
256 {
257 	struct dax_region *dax_region = dev_get_drvdata(dev);
258 
259 	return sprintf(buf, "%u\n", dax_region->align);
260 }
261 static struct device_attribute dev_attr_region_align =
262 		__ATTR(align, 0400, region_align_show, NULL);
263 
264 #define for_each_dax_region_resource(dax_region, res) \
265 	for (res = (dax_region)->res.child; res; res = res->sibling)
266 
dax_region_avail_size(struct dax_region * dax_region)267 static unsigned long long dax_region_avail_size(struct dax_region *dax_region)
268 {
269 	resource_size_t size = resource_size(&dax_region->res);
270 	struct resource *res;
271 
272 	device_lock_assert(dax_region->dev);
273 
274 	for_each_dax_region_resource(dax_region, res)
275 		size -= resource_size(res);
276 	return size;
277 }
278 
available_size_show(struct device * dev,struct device_attribute * attr,char * buf)279 static ssize_t available_size_show(struct device *dev,
280 		struct device_attribute *attr, char *buf)
281 {
282 	struct dax_region *dax_region = dev_get_drvdata(dev);
283 	unsigned long long size;
284 
285 	device_lock(dev);
286 	size = dax_region_avail_size(dax_region);
287 	device_unlock(dev);
288 
289 	return sprintf(buf, "%llu\n", size);
290 }
291 static DEVICE_ATTR_RO(available_size);
292 
seed_show(struct device * dev,struct device_attribute * attr,char * buf)293 static ssize_t seed_show(struct device *dev,
294 		struct device_attribute *attr, char *buf)
295 {
296 	struct dax_region *dax_region = dev_get_drvdata(dev);
297 	struct device *seed;
298 	ssize_t rc;
299 
300 	if (is_static(dax_region))
301 		return -EINVAL;
302 
303 	device_lock(dev);
304 	seed = dax_region->seed;
305 	rc = sprintf(buf, "%s\n", seed ? dev_name(seed) : "");
306 	device_unlock(dev);
307 
308 	return rc;
309 }
310 static DEVICE_ATTR_RO(seed);
311 
create_show(struct device * dev,struct device_attribute * attr,char * buf)312 static ssize_t create_show(struct device *dev,
313 		struct device_attribute *attr, char *buf)
314 {
315 	struct dax_region *dax_region = dev_get_drvdata(dev);
316 	struct device *youngest;
317 	ssize_t rc;
318 
319 	if (is_static(dax_region))
320 		return -EINVAL;
321 
322 	device_lock(dev);
323 	youngest = dax_region->youngest;
324 	rc = sprintf(buf, "%s\n", youngest ? dev_name(youngest) : "");
325 	device_unlock(dev);
326 
327 	return rc;
328 }
329 
create_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t len)330 static ssize_t create_store(struct device *dev, struct device_attribute *attr,
331 		const char *buf, size_t len)
332 {
333 	struct dax_region *dax_region = dev_get_drvdata(dev);
334 	unsigned long long avail;
335 	ssize_t rc;
336 	int val;
337 
338 	if (is_static(dax_region))
339 		return -EINVAL;
340 
341 	rc = kstrtoint(buf, 0, &val);
342 	if (rc)
343 		return rc;
344 	if (val != 1)
345 		return -EINVAL;
346 
347 	device_lock(dev);
348 	avail = dax_region_avail_size(dax_region);
349 	if (avail == 0)
350 		rc = -ENOSPC;
351 	else {
352 		struct dev_dax_data data = {
353 			.dax_region = dax_region,
354 			.size = 0,
355 			.id = -1,
356 		};
357 		struct dev_dax *dev_dax = devm_create_dev_dax(&data);
358 
359 		if (IS_ERR(dev_dax))
360 			rc = PTR_ERR(dev_dax);
361 		else {
362 			/*
363 			 * In support of crafting multiple new devices
364 			 * simultaneously multiple seeds can be created,
365 			 * but only the first one that has not been
366 			 * successfully bound is tracked as the region
367 			 * seed.
368 			 */
369 			if (!dax_region->seed)
370 				dax_region->seed = &dev_dax->dev;
371 			dax_region->youngest = &dev_dax->dev;
372 			rc = len;
373 		}
374 	}
375 	device_unlock(dev);
376 
377 	return rc;
378 }
379 static DEVICE_ATTR_RW(create);
380 
kill_dev_dax(struct dev_dax * dev_dax)381 void kill_dev_dax(struct dev_dax *dev_dax)
382 {
383 	struct dax_device *dax_dev = dev_dax->dax_dev;
384 	struct inode *inode = dax_inode(dax_dev);
385 
386 	kill_dax(dax_dev);
387 	unmap_mapping_range(inode->i_mapping, 0, 0, 1);
388 
389 	/*
390 	 * Dynamic dax region have the pgmap allocated via dev_kzalloc()
391 	 * and thus freed by devm. Clear the pgmap to not have stale pgmap
392 	 * ranges on probe() from previous reconfigurations of region devices.
393 	 */
394 	if (!static_dev_dax(dev_dax))
395 		dev_dax->pgmap = NULL;
396 }
397 EXPORT_SYMBOL_GPL(kill_dev_dax);
398 
trim_dev_dax_range(struct dev_dax * dev_dax)399 static void trim_dev_dax_range(struct dev_dax *dev_dax)
400 {
401 	int i = dev_dax->nr_range - 1;
402 	struct range *range = &dev_dax->ranges[i].range;
403 	struct dax_region *dax_region = dev_dax->region;
404 
405 	device_lock_assert(dax_region->dev);
406 	dev_dbg(&dev_dax->dev, "delete range[%d]: %#llx:%#llx\n", i,
407 		(unsigned long long)range->start,
408 		(unsigned long long)range->end);
409 
410 	__release_region(&dax_region->res, range->start, range_len(range));
411 	if (--dev_dax->nr_range == 0) {
412 		kfree(dev_dax->ranges);
413 		dev_dax->ranges = NULL;
414 	}
415 }
416 
free_dev_dax_ranges(struct dev_dax * dev_dax)417 static void free_dev_dax_ranges(struct dev_dax *dev_dax)
418 {
419 	while (dev_dax->nr_range)
420 		trim_dev_dax_range(dev_dax);
421 }
422 
unregister_dev_dax(void * dev)423 static void unregister_dev_dax(void *dev)
424 {
425 	struct dev_dax *dev_dax = to_dev_dax(dev);
426 
427 	dev_dbg(dev, "%s\n", __func__);
428 
429 	kill_dev_dax(dev_dax);
430 	free_dev_dax_ranges(dev_dax);
431 	device_del(dev);
432 	put_device(dev);
433 }
434 
435 /* a return value >= 0 indicates this invocation invalidated the id */
__free_dev_dax_id(struct dev_dax * dev_dax)436 static int __free_dev_dax_id(struct dev_dax *dev_dax)
437 {
438 	struct dax_region *dax_region = dev_dax->region;
439 	struct device *dev = &dev_dax->dev;
440 	int rc = dev_dax->id;
441 
442 	device_lock_assert(dev);
443 
444 	if (is_static(dax_region) || dev_dax->id < 0)
445 		return -1;
446 	ida_free(&dax_region->ida, dev_dax->id);
447 	dev_dax->id = -1;
448 	return rc;
449 }
450 
free_dev_dax_id(struct dev_dax * dev_dax)451 static int free_dev_dax_id(struct dev_dax *dev_dax)
452 {
453 	struct device *dev = &dev_dax->dev;
454 	int rc;
455 
456 	device_lock(dev);
457 	rc = __free_dev_dax_id(dev_dax);
458 	device_unlock(dev);
459 	return rc;
460 }
461 
delete_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t len)462 static ssize_t delete_store(struct device *dev, struct device_attribute *attr,
463 		const char *buf, size_t len)
464 {
465 	struct dax_region *dax_region = dev_get_drvdata(dev);
466 	struct dev_dax *dev_dax;
467 	struct device *victim;
468 	bool do_del = false;
469 	int rc;
470 
471 	if (is_static(dax_region))
472 		return -EINVAL;
473 
474 	victim = device_find_child_by_name(dax_region->dev, buf);
475 	if (!victim)
476 		return -ENXIO;
477 
478 	device_lock(dev);
479 	device_lock(victim);
480 	dev_dax = to_dev_dax(victim);
481 	if (victim->driver || dev_dax_size(dev_dax))
482 		rc = -EBUSY;
483 	else {
484 		/*
485 		 * Invalidate the device so it does not become active
486 		 * again, but always preserve device-id-0 so that
487 		 * /sys/bus/dax/ is guaranteed to be populated while any
488 		 * dax_region is registered.
489 		 */
490 		if (dev_dax->id > 0) {
491 			do_del = __free_dev_dax_id(dev_dax) >= 0;
492 			rc = len;
493 			if (dax_region->seed == victim)
494 				dax_region->seed = NULL;
495 			if (dax_region->youngest == victim)
496 				dax_region->youngest = NULL;
497 		} else
498 			rc = -EBUSY;
499 	}
500 	device_unlock(victim);
501 
502 	/* won the race to invalidate the device, clean it up */
503 	if (do_del)
504 		devm_release_action(dev, unregister_dev_dax, victim);
505 	device_unlock(dev);
506 	put_device(victim);
507 
508 	return rc;
509 }
510 static DEVICE_ATTR_WO(delete);
511 
dax_region_visible(struct kobject * kobj,struct attribute * a,int n)512 static umode_t dax_region_visible(struct kobject *kobj, struct attribute *a,
513 		int n)
514 {
515 	struct device *dev = container_of(kobj, struct device, kobj);
516 	struct dax_region *dax_region = dev_get_drvdata(dev);
517 
518 	if (is_static(dax_region))
519 		if (a == &dev_attr_available_size.attr
520 				|| a == &dev_attr_create.attr
521 				|| a == &dev_attr_seed.attr
522 				|| a == &dev_attr_delete.attr)
523 			return 0;
524 	return a->mode;
525 }
526 
527 static struct attribute *dax_region_attributes[] = {
528 	&dev_attr_available_size.attr,
529 	&dev_attr_region_size.attr,
530 	&dev_attr_region_align.attr,
531 	&dev_attr_create.attr,
532 	&dev_attr_seed.attr,
533 	&dev_attr_delete.attr,
534 	&dev_attr_id.attr,
535 	NULL,
536 };
537 
538 static const struct attribute_group dax_region_attribute_group = {
539 	.name = "dax_region",
540 	.attrs = dax_region_attributes,
541 	.is_visible = dax_region_visible,
542 };
543 
544 static const struct attribute_group *dax_region_attribute_groups[] = {
545 	&dax_region_attribute_group,
546 	NULL,
547 };
548 
dax_region_free(struct kref * kref)549 static void dax_region_free(struct kref *kref)
550 {
551 	struct dax_region *dax_region;
552 
553 	dax_region = container_of(kref, struct dax_region, kref);
554 	kfree(dax_region);
555 }
556 
dax_region_put(struct dax_region * dax_region)557 void dax_region_put(struct dax_region *dax_region)
558 {
559 	kref_put(&dax_region->kref, dax_region_free);
560 }
561 EXPORT_SYMBOL_GPL(dax_region_put);
562 
dax_region_unregister(void * region)563 static void dax_region_unregister(void *region)
564 {
565 	struct dax_region *dax_region = region;
566 
567 	sysfs_remove_groups(&dax_region->dev->kobj,
568 			dax_region_attribute_groups);
569 	dax_region_put(dax_region);
570 }
571 
alloc_dax_region(struct device * parent,int region_id,struct range * range,int target_node,unsigned int align,unsigned long flags)572 struct dax_region *alloc_dax_region(struct device *parent, int region_id,
573 		struct range *range, int target_node, unsigned int align,
574 		unsigned long flags)
575 {
576 	struct dax_region *dax_region;
577 
578 	/*
579 	 * The DAX core assumes that it can store its private data in
580 	 * parent->driver_data. This WARN is a reminder / safeguard for
581 	 * developers of device-dax drivers.
582 	 */
583 	if (dev_get_drvdata(parent)) {
584 		dev_WARN(parent, "dax core failed to setup private data\n");
585 		return NULL;
586 	}
587 
588 	if (!IS_ALIGNED(range->start, align)
589 			|| !IS_ALIGNED(range_len(range), align))
590 		return NULL;
591 
592 	dax_region = kzalloc(sizeof(*dax_region), GFP_KERNEL);
593 	if (!dax_region)
594 		return NULL;
595 
596 	dev_set_drvdata(parent, dax_region);
597 	kref_init(&dax_region->kref);
598 	dax_region->id = region_id;
599 	dax_region->align = align;
600 	dax_region->dev = parent;
601 	dax_region->target_node = target_node;
602 	ida_init(&dax_region->ida);
603 	dax_region->res = (struct resource) {
604 		.start = range->start,
605 		.end = range->end,
606 		.flags = IORESOURCE_MEM | flags,
607 	};
608 
609 	if (sysfs_create_groups(&parent->kobj, dax_region_attribute_groups)) {
610 		kfree(dax_region);
611 		return NULL;
612 	}
613 
614 	kref_get(&dax_region->kref);
615 	if (devm_add_action_or_reset(parent, dax_region_unregister, dax_region))
616 		return NULL;
617 	return dax_region;
618 }
619 EXPORT_SYMBOL_GPL(alloc_dax_region);
620 
dax_mapping_release(struct device * dev)621 static void dax_mapping_release(struct device *dev)
622 {
623 	struct dax_mapping *mapping = to_dax_mapping(dev);
624 	struct dev_dax *dev_dax = to_dev_dax(dev->parent);
625 
626 	ida_free(&dev_dax->ida, mapping->id);
627 	kfree(mapping);
628 }
629 
unregister_dax_mapping(void * data)630 static void unregister_dax_mapping(void *data)
631 {
632 	struct device *dev = data;
633 	struct dax_mapping *mapping = to_dax_mapping(dev);
634 	struct dev_dax *dev_dax = to_dev_dax(dev->parent);
635 	struct dax_region *dax_region = dev_dax->region;
636 
637 	dev_dbg(dev, "%s\n", __func__);
638 
639 	device_lock_assert(dax_region->dev);
640 
641 	dev_dax->ranges[mapping->range_id].mapping = NULL;
642 	mapping->range_id = -1;
643 
644 	device_del(dev);
645 	put_device(dev);
646 }
647 
get_dax_range(struct device * dev)648 static struct dev_dax_range *get_dax_range(struct device *dev)
649 {
650 	struct dax_mapping *mapping = to_dax_mapping(dev);
651 	struct dev_dax *dev_dax = to_dev_dax(dev->parent);
652 	struct dax_region *dax_region = dev_dax->region;
653 
654 	device_lock(dax_region->dev);
655 	if (mapping->range_id < 0) {
656 		device_unlock(dax_region->dev);
657 		return NULL;
658 	}
659 
660 	return &dev_dax->ranges[mapping->range_id];
661 }
662 
put_dax_range(struct dev_dax_range * dax_range)663 static void put_dax_range(struct dev_dax_range *dax_range)
664 {
665 	struct dax_mapping *mapping = dax_range->mapping;
666 	struct dev_dax *dev_dax = to_dev_dax(mapping->dev.parent);
667 	struct dax_region *dax_region = dev_dax->region;
668 
669 	device_unlock(dax_region->dev);
670 }
671 
start_show(struct device * dev,struct device_attribute * attr,char * buf)672 static ssize_t start_show(struct device *dev,
673 		struct device_attribute *attr, char *buf)
674 {
675 	struct dev_dax_range *dax_range;
676 	ssize_t rc;
677 
678 	dax_range = get_dax_range(dev);
679 	if (!dax_range)
680 		return -ENXIO;
681 	rc = sprintf(buf, "%#llx\n", dax_range->range.start);
682 	put_dax_range(dax_range);
683 
684 	return rc;
685 }
686 static DEVICE_ATTR(start, 0400, start_show, NULL);
687 
end_show(struct device * dev,struct device_attribute * attr,char * buf)688 static ssize_t end_show(struct device *dev,
689 		struct device_attribute *attr, char *buf)
690 {
691 	struct dev_dax_range *dax_range;
692 	ssize_t rc;
693 
694 	dax_range = get_dax_range(dev);
695 	if (!dax_range)
696 		return -ENXIO;
697 	rc = sprintf(buf, "%#llx\n", dax_range->range.end);
698 	put_dax_range(dax_range);
699 
700 	return rc;
701 }
702 static DEVICE_ATTR(end, 0400, end_show, NULL);
703 
pgoff_show(struct device * dev,struct device_attribute * attr,char * buf)704 static ssize_t pgoff_show(struct device *dev,
705 		struct device_attribute *attr, char *buf)
706 {
707 	struct dev_dax_range *dax_range;
708 	ssize_t rc;
709 
710 	dax_range = get_dax_range(dev);
711 	if (!dax_range)
712 		return -ENXIO;
713 	rc = sprintf(buf, "%#lx\n", dax_range->pgoff);
714 	put_dax_range(dax_range);
715 
716 	return rc;
717 }
718 static DEVICE_ATTR(page_offset, 0400, pgoff_show, NULL);
719 
720 static struct attribute *dax_mapping_attributes[] = {
721 	&dev_attr_start.attr,
722 	&dev_attr_end.attr,
723 	&dev_attr_page_offset.attr,
724 	NULL,
725 };
726 
727 static const struct attribute_group dax_mapping_attribute_group = {
728 	.attrs = dax_mapping_attributes,
729 };
730 
731 static const struct attribute_group *dax_mapping_attribute_groups[] = {
732 	&dax_mapping_attribute_group,
733 	NULL,
734 };
735 
736 static struct device_type dax_mapping_type = {
737 	.release = dax_mapping_release,
738 	.groups = dax_mapping_attribute_groups,
739 };
740 
devm_register_dax_mapping(struct dev_dax * dev_dax,int range_id)741 static int devm_register_dax_mapping(struct dev_dax *dev_dax, int range_id)
742 {
743 	struct dax_region *dax_region = dev_dax->region;
744 	struct dax_mapping *mapping;
745 	struct device *dev;
746 	int rc;
747 
748 	device_lock_assert(dax_region->dev);
749 
750 	if (dev_WARN_ONCE(&dev_dax->dev, !dax_region->dev->driver,
751 				"region disabled\n"))
752 		return -ENXIO;
753 
754 	mapping = kzalloc(sizeof(*mapping), GFP_KERNEL);
755 	if (!mapping)
756 		return -ENOMEM;
757 	mapping->range_id = range_id;
758 	mapping->id = ida_alloc(&dev_dax->ida, GFP_KERNEL);
759 	if (mapping->id < 0) {
760 		kfree(mapping);
761 		return -ENOMEM;
762 	}
763 	dev_dax->ranges[range_id].mapping = mapping;
764 	dev = &mapping->dev;
765 	device_initialize(dev);
766 	dev->parent = &dev_dax->dev;
767 	dev->type = &dax_mapping_type;
768 	dev_set_name(dev, "mapping%d", mapping->id);
769 	rc = device_add(dev);
770 	if (rc) {
771 		put_device(dev);
772 		return rc;
773 	}
774 
775 	rc = devm_add_action_or_reset(dax_region->dev, unregister_dax_mapping,
776 			dev);
777 	if (rc)
778 		return rc;
779 	return 0;
780 }
781 
alloc_dev_dax_range(struct dev_dax * dev_dax,u64 start,resource_size_t size)782 static int alloc_dev_dax_range(struct dev_dax *dev_dax, u64 start,
783 		resource_size_t size)
784 {
785 	struct dax_region *dax_region = dev_dax->region;
786 	struct resource *res = &dax_region->res;
787 	struct device *dev = &dev_dax->dev;
788 	struct dev_dax_range *ranges;
789 	unsigned long pgoff = 0;
790 	struct resource *alloc;
791 	int i, rc;
792 
793 	device_lock_assert(dax_region->dev);
794 
795 	/* handle the seed alloc special case */
796 	if (!size) {
797 		if (dev_WARN_ONCE(dev, dev_dax->nr_range,
798 					"0-size allocation must be first\n"))
799 			return -EBUSY;
800 		/* nr_range == 0 is elsewhere special cased as 0-size device */
801 		return 0;
802 	}
803 
804 	alloc = __request_region(res, start, size, dev_name(dev), 0);
805 	if (!alloc)
806 		return -ENOMEM;
807 
808 	ranges = krealloc(dev_dax->ranges, sizeof(*ranges)
809 			* (dev_dax->nr_range + 1), GFP_KERNEL);
810 	if (!ranges) {
811 		__release_region(res, alloc->start, resource_size(alloc));
812 		return -ENOMEM;
813 	}
814 
815 	for (i = 0; i < dev_dax->nr_range; i++)
816 		pgoff += PHYS_PFN(range_len(&ranges[i].range));
817 	dev_dax->ranges = ranges;
818 	ranges[dev_dax->nr_range++] = (struct dev_dax_range) {
819 		.pgoff = pgoff,
820 		.range = {
821 			.start = alloc->start,
822 			.end = alloc->end,
823 		},
824 	};
825 
826 	dev_dbg(dev, "alloc range[%d]: %pa:%pa\n", dev_dax->nr_range - 1,
827 			&alloc->start, &alloc->end);
828 	/*
829 	 * A dev_dax instance must be registered before mapping device
830 	 * children can be added. Defer to devm_create_dev_dax() to add
831 	 * the initial mapping device.
832 	 */
833 	if (!device_is_registered(&dev_dax->dev))
834 		return 0;
835 
836 	rc = devm_register_dax_mapping(dev_dax, dev_dax->nr_range - 1);
837 	if (rc)
838 		trim_dev_dax_range(dev_dax);
839 
840 	return rc;
841 }
842 
adjust_dev_dax_range(struct dev_dax * dev_dax,struct resource * res,resource_size_t size)843 static int adjust_dev_dax_range(struct dev_dax *dev_dax, struct resource *res, resource_size_t size)
844 {
845 	int last_range = dev_dax->nr_range - 1;
846 	struct dev_dax_range *dax_range = &dev_dax->ranges[last_range];
847 	struct dax_region *dax_region = dev_dax->region;
848 	bool is_shrink = resource_size(res) > size;
849 	struct range *range = &dax_range->range;
850 	struct device *dev = &dev_dax->dev;
851 	int rc;
852 
853 	device_lock_assert(dax_region->dev);
854 
855 	if (dev_WARN_ONCE(dev, !size, "deletion is handled by dev_dax_shrink\n"))
856 		return -EINVAL;
857 
858 	rc = adjust_resource(res, range->start, size);
859 	if (rc)
860 		return rc;
861 
862 	*range = (struct range) {
863 		.start = range->start,
864 		.end = range->start + size - 1,
865 	};
866 
867 	dev_dbg(dev, "%s range[%d]: %#llx:%#llx\n", is_shrink ? "shrink" : "extend",
868 			last_range, (unsigned long long) range->start,
869 			(unsigned long long) range->end);
870 
871 	return 0;
872 }
873 
size_show(struct device * dev,struct device_attribute * attr,char * buf)874 static ssize_t size_show(struct device *dev,
875 		struct device_attribute *attr, char *buf)
876 {
877 	struct dev_dax *dev_dax = to_dev_dax(dev);
878 	unsigned long long size;
879 
880 	device_lock(dev);
881 	size = dev_dax_size(dev_dax);
882 	device_unlock(dev);
883 
884 	return sprintf(buf, "%llu\n", size);
885 }
886 
alloc_is_aligned(struct dev_dax * dev_dax,resource_size_t size)887 static bool alloc_is_aligned(struct dev_dax *dev_dax, resource_size_t size)
888 {
889 	/*
890 	 * The minimum mapping granularity for a device instance is a
891 	 * single subsection, unless the arch says otherwise.
892 	 */
893 	return IS_ALIGNED(size, max_t(unsigned long, dev_dax->align, memremap_compat_align()));
894 }
895 
dev_dax_shrink(struct dev_dax * dev_dax,resource_size_t size)896 static int dev_dax_shrink(struct dev_dax *dev_dax, resource_size_t size)
897 {
898 	resource_size_t to_shrink = dev_dax_size(dev_dax) - size;
899 	struct dax_region *dax_region = dev_dax->region;
900 	struct device *dev = &dev_dax->dev;
901 	int i;
902 
903 	for (i = dev_dax->nr_range - 1; i >= 0; i--) {
904 		struct range *range = &dev_dax->ranges[i].range;
905 		struct dax_mapping *mapping = dev_dax->ranges[i].mapping;
906 		struct resource *adjust = NULL, *res;
907 		resource_size_t shrink;
908 
909 		shrink = min_t(u64, to_shrink, range_len(range));
910 		if (shrink >= range_len(range)) {
911 			devm_release_action(dax_region->dev,
912 					unregister_dax_mapping, &mapping->dev);
913 			trim_dev_dax_range(dev_dax);
914 			to_shrink -= shrink;
915 			if (!to_shrink)
916 				break;
917 			continue;
918 		}
919 
920 		for_each_dax_region_resource(dax_region, res)
921 			if (strcmp(res->name, dev_name(dev)) == 0
922 					&& res->start == range->start) {
923 				adjust = res;
924 				break;
925 			}
926 
927 		if (dev_WARN_ONCE(dev, !adjust || i != dev_dax->nr_range - 1,
928 					"failed to find matching resource\n"))
929 			return -ENXIO;
930 		return adjust_dev_dax_range(dev_dax, adjust, range_len(range)
931 				- shrink);
932 	}
933 	return 0;
934 }
935 
936 /*
937  * Only allow adjustments that preserve the relative pgoff of existing
938  * allocations. I.e. the dev_dax->ranges array is ordered by increasing pgoff.
939  */
adjust_ok(struct dev_dax * dev_dax,struct resource * res)940 static bool adjust_ok(struct dev_dax *dev_dax, struct resource *res)
941 {
942 	struct dev_dax_range *last;
943 	int i;
944 
945 	if (dev_dax->nr_range == 0)
946 		return false;
947 	if (strcmp(res->name, dev_name(&dev_dax->dev)) != 0)
948 		return false;
949 	last = &dev_dax->ranges[dev_dax->nr_range - 1];
950 	if (last->range.start != res->start || last->range.end != res->end)
951 		return false;
952 	for (i = 0; i < dev_dax->nr_range - 1; i++) {
953 		struct dev_dax_range *dax_range = &dev_dax->ranges[i];
954 
955 		if (dax_range->pgoff > last->pgoff)
956 			return false;
957 	}
958 
959 	return true;
960 }
961 
dev_dax_resize(struct dax_region * dax_region,struct dev_dax * dev_dax,resource_size_t size)962 static ssize_t dev_dax_resize(struct dax_region *dax_region,
963 		struct dev_dax *dev_dax, resource_size_t size)
964 {
965 	resource_size_t avail = dax_region_avail_size(dax_region), to_alloc;
966 	resource_size_t dev_size = dev_dax_size(dev_dax);
967 	struct resource *region_res = &dax_region->res;
968 	struct device *dev = &dev_dax->dev;
969 	struct resource *res, *first;
970 	resource_size_t alloc = 0;
971 	int rc;
972 
973 	if (dev->driver)
974 		return -EBUSY;
975 	if (size == dev_size)
976 		return 0;
977 	if (size > dev_size && size - dev_size > avail)
978 		return -ENOSPC;
979 	if (size < dev_size)
980 		return dev_dax_shrink(dev_dax, size);
981 
982 	to_alloc = size - dev_size;
983 	if (dev_WARN_ONCE(dev, !alloc_is_aligned(dev_dax, to_alloc),
984 			"resize of %pa misaligned\n", &to_alloc))
985 		return -ENXIO;
986 
987 	/*
988 	 * Expand the device into the unused portion of the region. This
989 	 * may involve adjusting the end of an existing resource, or
990 	 * allocating a new resource.
991 	 */
992 retry:
993 	first = region_res->child;
994 	if (!first)
995 		return alloc_dev_dax_range(dev_dax, dax_region->res.start, to_alloc);
996 
997 	rc = -ENOSPC;
998 	for (res = first; res; res = res->sibling) {
999 		struct resource *next = res->sibling;
1000 
1001 		/* space at the beginning of the region */
1002 		if (res == first && res->start > dax_region->res.start) {
1003 			alloc = min(res->start - dax_region->res.start, to_alloc);
1004 			rc = alloc_dev_dax_range(dev_dax, dax_region->res.start, alloc);
1005 			break;
1006 		}
1007 
1008 		alloc = 0;
1009 		/* space between allocations */
1010 		if (next && next->start > res->end + 1)
1011 			alloc = min(next->start - (res->end + 1), to_alloc);
1012 
1013 		/* space at the end of the region */
1014 		if (!alloc && !next && res->end < region_res->end)
1015 			alloc = min(region_res->end - res->end, to_alloc);
1016 
1017 		if (!alloc)
1018 			continue;
1019 
1020 		if (adjust_ok(dev_dax, res)) {
1021 			rc = adjust_dev_dax_range(dev_dax, res, resource_size(res) + alloc);
1022 			break;
1023 		}
1024 		rc = alloc_dev_dax_range(dev_dax, res->end + 1, alloc);
1025 		break;
1026 	}
1027 	if (rc)
1028 		return rc;
1029 	to_alloc -= alloc;
1030 	if (to_alloc)
1031 		goto retry;
1032 	return 0;
1033 }
1034 
size_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t len)1035 static ssize_t size_store(struct device *dev, struct device_attribute *attr,
1036 		const char *buf, size_t len)
1037 {
1038 	ssize_t rc;
1039 	unsigned long long val;
1040 	struct dev_dax *dev_dax = to_dev_dax(dev);
1041 	struct dax_region *dax_region = dev_dax->region;
1042 
1043 	rc = kstrtoull(buf, 0, &val);
1044 	if (rc)
1045 		return rc;
1046 
1047 	if (!alloc_is_aligned(dev_dax, val)) {
1048 		dev_dbg(dev, "%s: size: %lld misaligned\n", __func__, val);
1049 		return -EINVAL;
1050 	}
1051 
1052 	device_lock(dax_region->dev);
1053 	if (!dax_region->dev->driver) {
1054 		device_unlock(dax_region->dev);
1055 		return -ENXIO;
1056 	}
1057 	device_lock(dev);
1058 	rc = dev_dax_resize(dax_region, dev_dax, val);
1059 	device_unlock(dev);
1060 	device_unlock(dax_region->dev);
1061 
1062 	return rc == 0 ? len : rc;
1063 }
1064 static DEVICE_ATTR_RW(size);
1065 
range_parse(const char * opt,size_t len,struct range * range)1066 static ssize_t range_parse(const char *opt, size_t len, struct range *range)
1067 {
1068 	unsigned long long addr = 0;
1069 	char *start, *end, *str;
1070 	ssize_t rc = -EINVAL;
1071 
1072 	str = kstrdup(opt, GFP_KERNEL);
1073 	if (!str)
1074 		return rc;
1075 
1076 	end = str;
1077 	start = strsep(&end, "-");
1078 	if (!start || !end)
1079 		goto err;
1080 
1081 	rc = kstrtoull(start, 16, &addr);
1082 	if (rc)
1083 		goto err;
1084 	range->start = addr;
1085 
1086 	rc = kstrtoull(end, 16, &addr);
1087 	if (rc)
1088 		goto err;
1089 	range->end = addr;
1090 
1091 err:
1092 	kfree(str);
1093 	return rc;
1094 }
1095 
mapping_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t len)1096 static ssize_t mapping_store(struct device *dev, struct device_attribute *attr,
1097 		const char *buf, size_t len)
1098 {
1099 	struct dev_dax *dev_dax = to_dev_dax(dev);
1100 	struct dax_region *dax_region = dev_dax->region;
1101 	size_t to_alloc;
1102 	struct range r;
1103 	ssize_t rc;
1104 
1105 	rc = range_parse(buf, len, &r);
1106 	if (rc)
1107 		return rc;
1108 
1109 	rc = -ENXIO;
1110 	device_lock(dax_region->dev);
1111 	if (!dax_region->dev->driver) {
1112 		device_unlock(dax_region->dev);
1113 		return rc;
1114 	}
1115 	device_lock(dev);
1116 
1117 	to_alloc = range_len(&r);
1118 	if (alloc_is_aligned(dev_dax, to_alloc))
1119 		rc = alloc_dev_dax_range(dev_dax, r.start, to_alloc);
1120 	device_unlock(dev);
1121 	device_unlock(dax_region->dev);
1122 
1123 	return rc == 0 ? len : rc;
1124 }
1125 static DEVICE_ATTR_WO(mapping);
1126 
align_show(struct device * dev,struct device_attribute * attr,char * buf)1127 static ssize_t align_show(struct device *dev,
1128 		struct device_attribute *attr, char *buf)
1129 {
1130 	struct dev_dax *dev_dax = to_dev_dax(dev);
1131 
1132 	return sprintf(buf, "%d\n", dev_dax->align);
1133 }
1134 
dev_dax_validate_align(struct dev_dax * dev_dax)1135 static ssize_t dev_dax_validate_align(struct dev_dax *dev_dax)
1136 {
1137 	struct device *dev = &dev_dax->dev;
1138 	int i;
1139 
1140 	for (i = 0; i < dev_dax->nr_range; i++) {
1141 		size_t len = range_len(&dev_dax->ranges[i].range);
1142 
1143 		if (!alloc_is_aligned(dev_dax, len)) {
1144 			dev_dbg(dev, "%s: align %u invalid for range %d\n",
1145 				__func__, dev_dax->align, i);
1146 			return -EINVAL;
1147 		}
1148 	}
1149 
1150 	return 0;
1151 }
1152 
align_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t len)1153 static ssize_t align_store(struct device *dev, struct device_attribute *attr,
1154 		const char *buf, size_t len)
1155 {
1156 	struct dev_dax *dev_dax = to_dev_dax(dev);
1157 	struct dax_region *dax_region = dev_dax->region;
1158 	unsigned long val, align_save;
1159 	ssize_t rc;
1160 
1161 	rc = kstrtoul(buf, 0, &val);
1162 	if (rc)
1163 		return -ENXIO;
1164 
1165 	if (!dax_align_valid(val))
1166 		return -EINVAL;
1167 
1168 	device_lock(dax_region->dev);
1169 	if (!dax_region->dev->driver) {
1170 		device_unlock(dax_region->dev);
1171 		return -ENXIO;
1172 	}
1173 
1174 	device_lock(dev);
1175 	if (dev->driver) {
1176 		rc = -EBUSY;
1177 		goto out_unlock;
1178 	}
1179 
1180 	align_save = dev_dax->align;
1181 	dev_dax->align = val;
1182 	rc = dev_dax_validate_align(dev_dax);
1183 	if (rc)
1184 		dev_dax->align = align_save;
1185 out_unlock:
1186 	device_unlock(dev);
1187 	device_unlock(dax_region->dev);
1188 	return rc == 0 ? len : rc;
1189 }
1190 static DEVICE_ATTR_RW(align);
1191 
dev_dax_target_node(struct dev_dax * dev_dax)1192 static int dev_dax_target_node(struct dev_dax *dev_dax)
1193 {
1194 	struct dax_region *dax_region = dev_dax->region;
1195 
1196 	return dax_region->target_node;
1197 }
1198 
target_node_show(struct device * dev,struct device_attribute * attr,char * buf)1199 static ssize_t target_node_show(struct device *dev,
1200 		struct device_attribute *attr, char *buf)
1201 {
1202 	struct dev_dax *dev_dax = to_dev_dax(dev);
1203 
1204 	return sprintf(buf, "%d\n", dev_dax_target_node(dev_dax));
1205 }
1206 static DEVICE_ATTR_RO(target_node);
1207 
resource_show(struct device * dev,struct device_attribute * attr,char * buf)1208 static ssize_t resource_show(struct device *dev,
1209 		struct device_attribute *attr, char *buf)
1210 {
1211 	struct dev_dax *dev_dax = to_dev_dax(dev);
1212 	struct dax_region *dax_region = dev_dax->region;
1213 	unsigned long long start;
1214 
1215 	if (dev_dax->nr_range < 1)
1216 		start = dax_region->res.start;
1217 	else
1218 		start = dev_dax->ranges[0].range.start;
1219 
1220 	return sprintf(buf, "%#llx\n", start);
1221 }
1222 static DEVICE_ATTR(resource, 0400, resource_show, NULL);
1223 
modalias_show(struct device * dev,struct device_attribute * attr,char * buf)1224 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
1225 		char *buf)
1226 {
1227 	/*
1228 	 * We only ever expect to handle device-dax instances, i.e. the
1229 	 * @type argument to MODULE_ALIAS_DAX_DEVICE() is always zero
1230 	 */
1231 	return sprintf(buf, DAX_DEVICE_MODALIAS_FMT "\n", 0);
1232 }
1233 static DEVICE_ATTR_RO(modalias);
1234 
numa_node_show(struct device * dev,struct device_attribute * attr,char * buf)1235 static ssize_t numa_node_show(struct device *dev,
1236 		struct device_attribute *attr, char *buf)
1237 {
1238 	return sprintf(buf, "%d\n", dev_to_node(dev));
1239 }
1240 static DEVICE_ATTR_RO(numa_node);
1241 
dev_dax_visible(struct kobject * kobj,struct attribute * a,int n)1242 static umode_t dev_dax_visible(struct kobject *kobj, struct attribute *a, int n)
1243 {
1244 	struct device *dev = container_of(kobj, struct device, kobj);
1245 	struct dev_dax *dev_dax = to_dev_dax(dev);
1246 	struct dax_region *dax_region = dev_dax->region;
1247 
1248 	if (a == &dev_attr_target_node.attr && dev_dax_target_node(dev_dax) < 0)
1249 		return 0;
1250 	if (a == &dev_attr_numa_node.attr && !IS_ENABLED(CONFIG_NUMA))
1251 		return 0;
1252 	if (a == &dev_attr_mapping.attr && is_static(dax_region))
1253 		return 0;
1254 	if ((a == &dev_attr_align.attr ||
1255 	     a == &dev_attr_size.attr) && is_static(dax_region))
1256 		return 0444;
1257 	return a->mode;
1258 }
1259 
1260 static struct attribute *dev_dax_attributes[] = {
1261 	&dev_attr_modalias.attr,
1262 	&dev_attr_size.attr,
1263 	&dev_attr_mapping.attr,
1264 	&dev_attr_target_node.attr,
1265 	&dev_attr_align.attr,
1266 	&dev_attr_resource.attr,
1267 	&dev_attr_numa_node.attr,
1268 	NULL,
1269 };
1270 
1271 static const struct attribute_group dev_dax_attribute_group = {
1272 	.attrs = dev_dax_attributes,
1273 	.is_visible = dev_dax_visible,
1274 };
1275 
1276 static const struct attribute_group *dax_attribute_groups[] = {
1277 	&dev_dax_attribute_group,
1278 	NULL,
1279 };
1280 
dev_dax_release(struct device * dev)1281 static void dev_dax_release(struct device *dev)
1282 {
1283 	struct dev_dax *dev_dax = to_dev_dax(dev);
1284 	struct dax_region *dax_region = dev_dax->region;
1285 	struct dax_device *dax_dev = dev_dax->dax_dev;
1286 
1287 	put_dax(dax_dev);
1288 	free_dev_dax_id(dev_dax);
1289 	dax_region_put(dax_region);
1290 	kfree(dev_dax->pgmap);
1291 	kfree(dev_dax);
1292 }
1293 
1294 static const struct device_type dev_dax_type = {
1295 	.release = dev_dax_release,
1296 	.groups = dax_attribute_groups,
1297 };
1298 
devm_create_dev_dax(struct dev_dax_data * data)1299 struct dev_dax *devm_create_dev_dax(struct dev_dax_data *data)
1300 {
1301 	struct dax_region *dax_region = data->dax_region;
1302 	struct device *parent = dax_region->dev;
1303 	struct dax_device *dax_dev;
1304 	struct dev_dax *dev_dax;
1305 	struct inode *inode;
1306 	struct device *dev;
1307 	int rc;
1308 
1309 	dev_dax = kzalloc(sizeof(*dev_dax), GFP_KERNEL);
1310 	if (!dev_dax)
1311 		return ERR_PTR(-ENOMEM);
1312 
1313 	if (is_static(dax_region)) {
1314 		if (dev_WARN_ONCE(parent, data->id < 0,
1315 				"dynamic id specified to static region\n")) {
1316 			rc = -EINVAL;
1317 			goto err_id;
1318 		}
1319 
1320 		dev_dax->id = data->id;
1321 	} else {
1322 		if (dev_WARN_ONCE(parent, data->id >= 0,
1323 				"static id specified to dynamic region\n")) {
1324 			rc = -EINVAL;
1325 			goto err_id;
1326 		}
1327 
1328 		rc = ida_alloc(&dax_region->ida, GFP_KERNEL);
1329 		if (rc < 0)
1330 			goto err_id;
1331 		dev_dax->id = rc;
1332 	}
1333 
1334 	dev_dax->region = dax_region;
1335 	dev = &dev_dax->dev;
1336 	device_initialize(dev);
1337 	dev_set_name(dev, "dax%d.%d", dax_region->id, dev_dax->id);
1338 
1339 	rc = alloc_dev_dax_range(dev_dax, dax_region->res.start, data->size);
1340 	if (rc)
1341 		goto err_range;
1342 
1343 	if (data->pgmap) {
1344 		dev_WARN_ONCE(parent, !is_static(dax_region),
1345 			"custom dev_pagemap requires a static dax_region\n");
1346 
1347 		dev_dax->pgmap = kmemdup(data->pgmap,
1348 				sizeof(struct dev_pagemap), GFP_KERNEL);
1349 		if (!dev_dax->pgmap) {
1350 			rc = -ENOMEM;
1351 			goto err_pgmap;
1352 		}
1353 	}
1354 
1355 	/*
1356 	 * No dax_operations since there is no access to this device outside of
1357 	 * mmap of the resulting character device.
1358 	 */
1359 	dax_dev = alloc_dax(dev_dax, NULL);
1360 	if (IS_ERR(dax_dev)) {
1361 		rc = PTR_ERR(dax_dev);
1362 		goto err_alloc_dax;
1363 	}
1364 	set_dax_synchronous(dax_dev);
1365 	set_dax_nocache(dax_dev);
1366 	set_dax_nomc(dax_dev);
1367 
1368 	/* a device_dax instance is dead while the driver is not attached */
1369 	kill_dax(dax_dev);
1370 
1371 	dev_dax->dax_dev = dax_dev;
1372 	dev_dax->target_node = dax_region->target_node;
1373 	dev_dax->align = dax_region->align;
1374 	ida_init(&dev_dax->ida);
1375 	kref_get(&dax_region->kref);
1376 
1377 	inode = dax_inode(dax_dev);
1378 	dev->devt = inode->i_rdev;
1379 	dev->bus = &dax_bus_type;
1380 	dev->parent = parent;
1381 	dev->type = &dev_dax_type;
1382 
1383 	rc = device_add(dev);
1384 	if (rc) {
1385 		kill_dev_dax(dev_dax);
1386 		put_device(dev);
1387 		return ERR_PTR(rc);
1388 	}
1389 
1390 	rc = devm_add_action_or_reset(dax_region->dev, unregister_dev_dax, dev);
1391 	if (rc)
1392 		return ERR_PTR(rc);
1393 
1394 	/* register mapping device for the initial allocation range */
1395 	if (dev_dax->nr_range && range_len(&dev_dax->ranges[0].range)) {
1396 		rc = devm_register_dax_mapping(dev_dax, 0);
1397 		if (rc)
1398 			return ERR_PTR(rc);
1399 	}
1400 
1401 	return dev_dax;
1402 
1403 err_alloc_dax:
1404 	kfree(dev_dax->pgmap);
1405 err_pgmap:
1406 	free_dev_dax_ranges(dev_dax);
1407 err_range:
1408 	free_dev_dax_id(dev_dax);
1409 err_id:
1410 	kfree(dev_dax);
1411 
1412 	return ERR_PTR(rc);
1413 }
1414 EXPORT_SYMBOL_GPL(devm_create_dev_dax);
1415 
1416 static int match_always_count;
1417 
__dax_driver_register(struct dax_device_driver * dax_drv,struct module * module,const char * mod_name)1418 int __dax_driver_register(struct dax_device_driver *dax_drv,
1419 		struct module *module, const char *mod_name)
1420 {
1421 	struct device_driver *drv = &dax_drv->drv;
1422 	int rc = 0;
1423 
1424 	/*
1425 	 * dax_bus_probe() calls dax_drv->probe() unconditionally.
1426 	 * So better be safe than sorry and ensure it is provided.
1427 	 */
1428 	if (!dax_drv->probe)
1429 		return -EINVAL;
1430 
1431 	INIT_LIST_HEAD(&dax_drv->ids);
1432 	drv->owner = module;
1433 	drv->name = mod_name;
1434 	drv->mod_name = mod_name;
1435 	drv->bus = &dax_bus_type;
1436 
1437 	/* there can only be one default driver */
1438 	mutex_lock(&dax_bus_lock);
1439 	match_always_count += dax_drv->match_always;
1440 	if (match_always_count > 1) {
1441 		match_always_count--;
1442 		WARN_ON(1);
1443 		rc = -EINVAL;
1444 	}
1445 	mutex_unlock(&dax_bus_lock);
1446 	if (rc)
1447 		return rc;
1448 
1449 	rc = driver_register(drv);
1450 	if (rc && dax_drv->match_always) {
1451 		mutex_lock(&dax_bus_lock);
1452 		match_always_count -= dax_drv->match_always;
1453 		mutex_unlock(&dax_bus_lock);
1454 	}
1455 
1456 	return rc;
1457 }
1458 EXPORT_SYMBOL_GPL(__dax_driver_register);
1459 
dax_driver_unregister(struct dax_device_driver * dax_drv)1460 void dax_driver_unregister(struct dax_device_driver *dax_drv)
1461 {
1462 	struct device_driver *drv = &dax_drv->drv;
1463 	struct dax_id *dax_id, *_id;
1464 
1465 	mutex_lock(&dax_bus_lock);
1466 	match_always_count -= dax_drv->match_always;
1467 	list_for_each_entry_safe(dax_id, _id, &dax_drv->ids, list) {
1468 		list_del(&dax_id->list);
1469 		kfree(dax_id);
1470 	}
1471 	mutex_unlock(&dax_bus_lock);
1472 	driver_unregister(drv);
1473 }
1474 EXPORT_SYMBOL_GPL(dax_driver_unregister);
1475 
dax_bus_init(void)1476 int __init dax_bus_init(void)
1477 {
1478 	return bus_register(&dax_bus_type);
1479 }
1480 
dax_bus_exit(void)1481 void __exit dax_bus_exit(void)
1482 {
1483 	bus_unregister(&dax_bus_type);
1484 }
1485