summaryrefslogtreecommitdiffstats
path: root/drivers/dax/bus.c
blob: 5681685002175d9d91e2dd3288d0e8240a71f41d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
// SPDX-License-Identifier: GPL-2.0
/* Copyright(c) 2017-2018 Intel Corporation. All rights reserved. */
#include <linux/memremap.h>
#include <linux/device.h>
#include <linux/mutex.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/dax.h>
#include "dax-private.h"
#include "bus.h"

static struct class *dax_class;

static DEFINE_MUTEX(dax_bus_lock);

#define DAX_NAME_LEN 30
struct dax_id {
	struct list_head list;
	char dev_name[DAX_NAME_LEN];
};

static int dax_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
{
	/*
	 * We only ever expect to handle device-dax instances, i.e. the
	 * @type argument to MODULE_ALIAS_DAX_DEVICE() is always zero
	 */
	return add_uevent_var(env, "MODALIAS=" DAX_DEVICE_MODALIAS_FMT, 0);
}

static struct dax_device_driver *to_dax_drv(struct device_driver *drv)
{
	return container_of(drv, struct dax_device_driver, drv);
}

static struct dax_id *__dax_match_id(struct dax_device_driver *dax_drv,
		const char *dev_name)
{
	struct dax_id *dax_id;

	lockdep_assert_held(&dax_bus_lock);

	list_for_each_entry(dax_id, &dax_drv->ids, list)
		if (sysfs_streq(dax_id->dev_name, dev_name))
			return dax_id;
	return NULL;
}

static int dax_match_id(struct dax_device_driver *dax_drv, struct device *dev)
{
	int match;

	mutex_lock(&dax_bus_lock);
	match = !!__dax_match_id(dax_drv, dev_name(dev));
	mutex_unlock(&dax_bus_lock);

	return match;
}

static ssize_t do_id_store(struct device_driver *drv, const char *buf,
		size_t count, bool add)
{
	struct dax_device_driver *dax_drv = to_dax_drv(drv);
	unsigned int region_id, id;
	char devname[DAX_NAME_LEN];
	struct dax_id *dax_id;
	ssize_t rc = count;
	int fields;

	fields = sscanf(buf, "dax%d.%d", &region_id, &id);
	if (fields != 2)
		return -EINVAL;
	sprintf(devname, "dax%d.%d", region_id, id);
	if (!sysfs_streq(buf, devname))
		return -EINVAL;

	mutex_lock(&dax_bus_lock);
	dax_id = __dax_match_id(dax_drv, buf);
	if (!dax_id) {
		if (add) {
			dax_id = kzalloc(sizeof(*dax_id), GFP_KERNEL);
			if (dax_id) {
				strncpy(dax_id->dev_name, buf, DAX_NAME_LEN);
				list_add(&dax_id->list, &dax_drv->ids);
			} else
				rc = -ENOMEM;
		} else
			/* nothing to remove */;
	} else if (!add) {
		list_del(&dax_id->list);
		kfree(dax_id);
	} else
		/* dax_id already added */;
	mutex_unlock(&dax_bus_lock);
	return rc;
}

static ssize_t new_id_store(struct device_driver *drv, const char *buf,
		size_t count)
{
	return do_id_store(drv, buf, count, true);
}
static DRIVER_ATTR_WO(new_id);

static ssize_t remove_id_store(struct device_driver *drv, const char *buf,
		size_t count)
{
	return do_id_store(drv, buf, count, false);
}
static DRIVER_ATTR_WO(remove_id);

static struct attribute *dax_drv_attrs[] = {
	&driver_attr_new_id.attr,
	&driver_attr_remove_id.attr,
	NULL,
};
ATTRIBUTE_GROUPS(dax_drv);

static int dax_bus_match(struct device *dev, struct device_driver *drv);

static struct bus_type dax_bus_type = {
	.name = "dax",
	.uevent = dax_bus_uevent,
	.match = dax_bus_match,
	.drv_groups = dax_drv_groups,
};

static int dax_bus_match(struct device *dev, struct device_driver *drv)
{
	struct dax_device_driver *dax_drv = to_dax_drv(drv);

	/*
	 * All but the 'device-dax' driver, which has 'match_always'
	 * set, requires an exact id match.
	 */
	if (dax_drv->match_always)
		return 1;

	return dax_match_id(dax_drv, dev);
}

/*
 * Rely on the fact that drvdata is set before the attributes are
 * registered, and that the attributes are unregistered before drvdata
 * is cleared to assume that drvdata is always valid.
 */
static ssize_t id_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct dax_region *dax_region = dev_get_drvdata(dev);

	return sprintf(buf, "%d\n", dax_region->id);
}
static DEVICE_ATTR_RO(id);

static ssize_t region_size_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct dax_region *dax_region = dev_get_drvdata(dev);

	return sprintf(buf, "%llu\n", (unsigned long long)
			resource_size(&dax_region->res));
}
static struct device_attribute dev_attr_region_size = __ATTR(size, 0444,
		region_size_show, NULL);

static ssize_t align_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct dax_region *dax_region = dev_get_drvdata(dev);

	return sprintf(buf, "%u\n", dax_region->align);
}
static DEVICE_ATTR_RO(align);

static struct attribute *dax_region_attributes[] = {
	&dev_attr_region_size.attr,
	&dev_attr_align.attr,
	&dev_attr_id.attr,
	NULL,
};

static const struct attribute_group dax_region_attribute_group = {
	.name = "dax_region",
	.attrs = dax_region_attributes,
};

static const struct attribute_group *dax_region_attribute_groups[] = {
	&dax_region_attribute_group,
	NULL,
};

static void dax_region_free(struct kref *kref)
{
	struct dax_region *dax_region;

	dax_region = container_of(kref, struct dax_region, kref);
	kfree(dax_region);
}

void dax_region_put(struct dax_region *dax_region)
{
	kref_put(&dax_region->kref, dax_region_free);
}
EXPORT_SYMBOL_GPL(dax_region_put);

static void dax_region_unregister(void *region)
{
	struct dax_region *dax_region = region;

	sysfs_remove_groups(&dax_region->dev->kobj,
			dax_region_attribute_groups);
	dax_region_put(dax_region);
}

struct dax_region *alloc_dax_region(struct device *parent, int region_id,
		struct resource *res, unsigned int align,
		unsigned long pfn_flags)
{
	struct dax_region *dax_region;

	/*
	 * The DAX core assumes that it can store its private data in
	 * parent->driver_data. This WARN is a reminder / safeguard for
	 * developers of device-dax drivers.
	 */
	if (dev_get_drvdata(parent)) {
		dev_WARN(parent, "dax core failed to setup private data\n");
		return NULL;
	}

	if (!IS_ALIGNED(res->start, align)
			|| !IS_ALIGNED(resource_size(res), align))
		return NULL;

	dax_region = kzalloc(sizeof(*dax_region), GFP_KERNEL);
	if (!dax_region)
		return NULL;

	dev_set_drvdata(parent, dax_region);
	memcpy(&dax_region->res, res, sizeof(*res));
	dax_region->pfn_flags = pfn_flags;
	kref_init(&dax_region->kref);
	dax_region->id = region_id;
	dax_region->align = align;
	dax_region->dev = parent;
	if (sysfs_create_groups(&parent->kobj, dax_region_attribute_groups)) {
		kfree(dax_region);
		return NULL;
	}

	kref_get(&dax_region->kref);
	if (devm_add_action_or_reset(parent, dax_region_unregister, dax_region))
		return NULL;
	return dax_region;
}
EXPORT_SYMBOL_GPL(alloc_dax_region);

static ssize_t size_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct dev_dax *dev_dax = to_dev_dax(dev);
	unsigned long long size = resource_size(&dev_dax->region->res);

	return sprintf(buf, "%llu\n", size);
}
static DEVICE_ATTR_RO(size);

static struct attribute *dev_dax_attributes[] = {
	&dev_attr_size.attr,
	NULL,
};

static const struct attribute_group dev_dax_attribute_group = {
	.attrs = dev_dax_attributes,
};

static const struct attribute_group *dax_attribute_groups[] = {
	&dev_dax_attribute_group,
	NULL,
};

void kill_dev_dax(struct dev_dax *dev_dax)
{
	struct dax_device *dax_dev = dev_dax->dax_dev;
	struct inode *inode = dax_inode(dax_dev);

	kill_dax(dax_dev);
	unmap_mapping_range(inode->i_mapping, 0, 0, 1);
}
EXPORT_SYMBOL_GPL(kill_dev_dax);

static void dev_dax_release(struct device *dev)
{
	struct dev_dax *dev_dax = to_dev_dax(dev);
	struct dax_region *dax_region = dev_dax->region;
	struct dax_device *dax_dev = dev_dax->dax_dev;

	dax_region_put(dax_region);
	put_dax(dax_dev);
	kfree(dev_dax);
}

static void unregister_dev_dax(void *dev)
{
	struct dev_dax *dev_dax = to_dev_dax(dev);

	dev_dbg(dev, "%s\n", __func__);

	kill_dev_dax(dev_dax);
	device_del(dev);
	put_device(dev);
}

struct dev_dax *__devm_create_dev_dax(struct dax_region *dax_region, int id,
		struct dev_pagemap *pgmap, enum dev_dax_subsys subsys)
{
	struct device *parent = dax_region->dev;
	struct dax_device *dax_dev;
	struct dev_dax *dev_dax;
	struct inode *inode;
	struct device *dev;
	int rc = -ENOMEM;

	if (id < 0)
		return ERR_PTR(-EINVAL);

	dev_dax = kzalloc(sizeof(*dev_dax), GFP_KERNEL);
	if (!dev_dax)
		return ERR_PTR(-ENOMEM);

	memcpy(&dev_dax->pgmap, pgmap, sizeof(*pgmap));

	/*
	 * No 'host' or dax_operations since there is no access to this
	 * device outside of mmap of the resulting character device.
	 */
	dax_dev = alloc_dax(dev_dax, NULL, NULL);
	if (!dax_dev)
		goto err;

	/* a device_dax instance is dead while the driver is not attached */
	kill_dax(dax_dev);

	/* from here on we're committed to teardown via dax_dev_release() */
	dev = &dev_dax->dev;
	device_initialize(dev);

	dev_dax->dax_dev = dax_dev;
	dev_dax->region = dax_region;
	kref_get(&dax_region->kref);

	inode = dax_inode(dax_dev);
	dev->devt = inode->i_rdev;
	if (subsys == DEV_DAX_BUS)
		dev->bus = &dax_bus_type;
	else
		dev->class = dax_class;
	dev->parent = parent;
	dev->groups = dax_attribute_groups;
	dev->release = dev_dax_release;
	dev_set_name(dev, "dax%d.%d", dax_region->id, id);

	rc = device_add(dev);
	if (rc) {
		kill_dev_dax(dev_dax);
		put_device(dev);
		return ERR_PTR(rc);
	}

	rc = devm_add_action_or_reset(dax_region->dev, unregister_dev_dax, dev);
	if (rc)
		return ERR_PTR(rc);

	return dev_dax;

 err:
	kfree(dev_dax);

	return ERR_PTR(rc);
}
EXPORT_SYMBOL_GPL(__devm_create_dev_dax);

static int match_always_count;

int __dax_driver_register(struct dax_device_driver *dax_drv,
		struct module *module, const char *mod_name)
{
	struct device_driver *drv = &dax_drv->drv;
	int rc = 0;

	INIT_LIST_HEAD(&dax_drv->ids);
	drv->owner = module;
	drv->name = mod_name;
	drv->mod_name = mod_name;
	drv->bus = &dax_bus_type;

	/* there can only be one default driver */
	mutex_lock(&dax_bus_lock);
	match_always_count += dax_drv->match_always;
	if (match_always_count > 1) {
		match_always_count--;
		WARN_ON(1);
		rc = -EINVAL;
	}
	mutex_unlock(&dax_bus_lock);
	if (rc)
		return rc;
	return driver_register(drv);
}
EXPORT_SYMBOL_GPL(__dax_driver_register);

void dax_driver_unregister(struct dax_device_driver *dax_drv)
{
	struct device_driver *drv = &dax_drv->drv;
	struct dax_id *dax_id, *_id;

	mutex_lock(&dax_bus_lock);
	match_always_count -= dax_drv->match_always;
	list_for_each_entry_safe(dax_id, _id, &dax_drv->ids, list) {
		list_del(&dax_id->list);
		kfree(dax_id);
	}
	mutex_unlock(&dax_bus_lock);
	driver_unregister(drv);
}
EXPORT_SYMBOL_GPL(dax_driver_unregister);

int __init dax_bus_init(void)
{
	int rc;

	if (IS_ENABLED(CONFIG_DEV_DAX_PMEM_COMPAT)) {
		dax_class = class_create(THIS_MODULE, "dax");
		if (IS_ERR(dax_class))
			return PTR_ERR(dax_class);
	}

	rc = bus_register(&dax_bus_type);
	if (rc)
		class_destroy(dax_class);
	return rc;
}

void __exit dax_bus_exit(void)
{
	bus_unregister(&dax_bus_type);
	class_destroy(dax_class);
}