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 "dax-private.h" 10 #include "bus.h" 11 12 static DEFINE_MUTEX(dax_bus_lock); 13 14 #define DAX_NAME_LEN 30 15 struct dax_id { 16 struct list_head list; 17 char dev_name[DAX_NAME_LEN]; 18 }; 19 20 static int dax_bus_uevent(struct device *dev, struct kobj_uevent_env *env) 21 { 22 /* 23 * We only ever expect to handle device-dax instances, i.e. the 24 * @type argument to MODULE_ALIAS_DAX_DEVICE() is always zero 25 */ 26 return add_uevent_var(env, "MODALIAS=" DAX_DEVICE_MODALIAS_FMT, 0); 27 } 28 29 static struct dax_device_driver *to_dax_drv(struct device_driver *drv) 30 { 31 return container_of(drv, struct dax_device_driver, drv); 32 } 33 34 static struct dax_id *__dax_match_id(struct dax_device_driver *dax_drv, 35 const char *dev_name) 36 { 37 struct dax_id *dax_id; 38 39 lockdep_assert_held(&dax_bus_lock); 40 41 list_for_each_entry(dax_id, &dax_drv->ids, list) 42 if (sysfs_streq(dax_id->dev_name, dev_name)) 43 return dax_id; 44 return NULL; 45 } 46 47 static int dax_match_id(struct dax_device_driver *dax_drv, struct device *dev) 48 { 49 int match; 50 51 mutex_lock(&dax_bus_lock); 52 match = !!__dax_match_id(dax_drv, dev_name(dev)); 53 mutex_unlock(&dax_bus_lock); 54 55 return match; 56 } 57 58 static ssize_t do_id_store(struct device_driver *drv, const char *buf, 59 size_t count, bool add) 60 { 61 struct dax_device_driver *dax_drv = to_dax_drv(drv); 62 unsigned int region_id, id; 63 char devname[DAX_NAME_LEN]; 64 struct dax_id *dax_id; 65 ssize_t rc = count; 66 int fields; 67 68 fields = sscanf(buf, "dax%d.%d", ®ion_id, &id); 69 if (fields != 2) 70 return -EINVAL; 71 sprintf(devname, "dax%d.%d", region_id, id); 72 if (!sysfs_streq(buf, devname)) 73 return -EINVAL; 74 75 mutex_lock(&dax_bus_lock); 76 dax_id = __dax_match_id(dax_drv, buf); 77 if (!dax_id) { 78 if (add) { 79 dax_id = kzalloc(sizeof(*dax_id), GFP_KERNEL); 80 if (dax_id) { 81 strncpy(dax_id->dev_name, buf, DAX_NAME_LEN); 82 list_add(&dax_id->list, &dax_drv->ids); 83 } else 84 rc = -ENOMEM; 85 } else 86 /* nothing to remove */; 87 } else if (!add) { 88 list_del(&dax_id->list); 89 kfree(dax_id); 90 } else 91 /* dax_id already added */; 92 mutex_unlock(&dax_bus_lock); 93 return rc; 94 } 95 96 static ssize_t new_id_store(struct device_driver *drv, const char *buf, 97 size_t count) 98 { 99 return do_id_store(drv, buf, count, true); 100 } 101 static DRIVER_ATTR_WO(new_id); 102 103 static ssize_t remove_id_store(struct device_driver *drv, const char *buf, 104 size_t count) 105 { 106 return do_id_store(drv, buf, count, false); 107 } 108 static DRIVER_ATTR_WO(remove_id); 109 110 static struct attribute *dax_drv_attrs[] = { 111 &driver_attr_new_id.attr, 112 &driver_attr_remove_id.attr, 113 NULL, 114 }; 115 ATTRIBUTE_GROUPS(dax_drv); 116 117 static int dax_bus_match(struct device *dev, struct device_driver *drv); 118 119 static struct bus_type dax_bus_type = { 120 .name = "dax", 121 .uevent = dax_bus_uevent, 122 .match = dax_bus_match, 123 .drv_groups = dax_drv_groups, 124 }; 125 126 static int dax_bus_match(struct device *dev, struct device_driver *drv) 127 { 128 struct dax_device_driver *dax_drv = to_dax_drv(drv); 129 130 /* 131 * All but the 'device-dax' driver, which has 'match_always' 132 * set, requires an exact id match. 133 */ 134 if (dax_drv->match_always) 135 return 1; 136 137 return dax_match_id(dax_drv, dev); 138 } 139 140 /* 141 * Rely on the fact that drvdata is set before the attributes are 142 * registered, and that the attributes are unregistered before drvdata 143 * is cleared to assume that drvdata is always valid. 144 */ 145 static ssize_t id_show(struct device *dev, 146 struct device_attribute *attr, char *buf) 147 { 148 struct dax_region *dax_region = dev_get_drvdata(dev); 149 150 return sprintf(buf, "%d\n", dax_region->id); 151 } 152 static DEVICE_ATTR_RO(id); 153 154 static ssize_t region_size_show(struct device *dev, 155 struct device_attribute *attr, char *buf) 156 { 157 struct dax_region *dax_region = dev_get_drvdata(dev); 158 159 return sprintf(buf, "%llu\n", (unsigned long long) 160 resource_size(&dax_region->res)); 161 } 162 static struct device_attribute dev_attr_region_size = __ATTR(size, 0444, 163 region_size_show, NULL); 164 165 static ssize_t align_show(struct device *dev, 166 struct device_attribute *attr, char *buf) 167 { 168 struct dax_region *dax_region = dev_get_drvdata(dev); 169 170 return sprintf(buf, "%u\n", dax_region->align); 171 } 172 static DEVICE_ATTR_RO(align); 173 174 static struct attribute *dax_region_attributes[] = { 175 &dev_attr_region_size.attr, 176 &dev_attr_align.attr, 177 &dev_attr_id.attr, 178 NULL, 179 }; 180 181 static const struct attribute_group dax_region_attribute_group = { 182 .name = "dax_region", 183 .attrs = dax_region_attributes, 184 }; 185 186 static const struct attribute_group *dax_region_attribute_groups[] = { 187 &dax_region_attribute_group, 188 NULL, 189 }; 190 191 static void dax_region_free(struct kref *kref) 192 { 193 struct dax_region *dax_region; 194 195 dax_region = container_of(kref, struct dax_region, kref); 196 kfree(dax_region); 197 } 198 199 void dax_region_put(struct dax_region *dax_region) 200 { 201 kref_put(&dax_region->kref, dax_region_free); 202 } 203 EXPORT_SYMBOL_GPL(dax_region_put); 204 205 static void dax_region_unregister(void *region) 206 { 207 struct dax_region *dax_region = region; 208 209 sysfs_remove_groups(&dax_region->dev->kobj, 210 dax_region_attribute_groups); 211 dax_region_put(dax_region); 212 } 213 214 struct dax_region *alloc_dax_region(struct device *parent, int region_id, 215 struct resource *res, unsigned int align, 216 unsigned long pfn_flags) 217 { 218 struct dax_region *dax_region; 219 220 /* 221 * The DAX core assumes that it can store its private data in 222 * parent->driver_data. This WARN is a reminder / safeguard for 223 * developers of device-dax drivers. 224 */ 225 if (dev_get_drvdata(parent)) { 226 dev_WARN(parent, "dax core failed to setup private data\n"); 227 return NULL; 228 } 229 230 if (!IS_ALIGNED(res->start, align) 231 || !IS_ALIGNED(resource_size(res), align)) 232 return NULL; 233 234 dax_region = kzalloc(sizeof(*dax_region), GFP_KERNEL); 235 if (!dax_region) 236 return NULL; 237 238 dev_set_drvdata(parent, dax_region); 239 memcpy(&dax_region->res, res, sizeof(*res)); 240 dax_region->pfn_flags = pfn_flags; 241 kref_init(&dax_region->kref); 242 dax_region->id = region_id; 243 dax_region->align = align; 244 dax_region->dev = parent; 245 if (sysfs_create_groups(&parent->kobj, dax_region_attribute_groups)) { 246 kfree(dax_region); 247 return NULL; 248 } 249 250 kref_get(&dax_region->kref); 251 if (devm_add_action_or_reset(parent, dax_region_unregister, dax_region)) 252 return NULL; 253 return dax_region; 254 } 255 EXPORT_SYMBOL_GPL(alloc_dax_region); 256 257 static ssize_t size_show(struct device *dev, 258 struct device_attribute *attr, char *buf) 259 { 260 struct dev_dax *dev_dax = to_dev_dax(dev); 261 unsigned long long size = resource_size(&dev_dax->region->res); 262 263 return sprintf(buf, "%llu\n", size); 264 } 265 static DEVICE_ATTR_RO(size); 266 267 static struct attribute *dev_dax_attributes[] = { 268 &dev_attr_size.attr, 269 NULL, 270 }; 271 272 static const struct attribute_group dev_dax_attribute_group = { 273 .attrs = dev_dax_attributes, 274 }; 275 276 static const struct attribute_group *dax_attribute_groups[] = { 277 &dev_dax_attribute_group, 278 NULL, 279 }; 280 281 void kill_dev_dax(struct dev_dax *dev_dax) 282 { 283 struct dax_device *dax_dev = dev_dax->dax_dev; 284 struct inode *inode = dax_inode(dax_dev); 285 286 kill_dax(dax_dev); 287 unmap_mapping_range(inode->i_mapping, 0, 0, 1); 288 } 289 EXPORT_SYMBOL_GPL(kill_dev_dax); 290 291 static void dev_dax_release(struct device *dev) 292 { 293 struct dev_dax *dev_dax = to_dev_dax(dev); 294 struct dax_region *dax_region = dev_dax->region; 295 struct dax_device *dax_dev = dev_dax->dax_dev; 296 297 dax_region_put(dax_region); 298 put_dax(dax_dev); 299 kfree(dev_dax); 300 } 301 302 static void unregister_dev_dax(void *dev) 303 { 304 struct dev_dax *dev_dax = to_dev_dax(dev); 305 306 dev_dbg(dev, "%s\n", __func__); 307 308 kill_dev_dax(dev_dax); 309 device_del(dev); 310 put_device(dev); 311 } 312 313 struct dev_dax *devm_create_dev_dax(struct dax_region *dax_region, int id, 314 struct dev_pagemap *pgmap) 315 { 316 struct device *parent = dax_region->dev; 317 struct dax_device *dax_dev; 318 struct dev_dax *dev_dax; 319 struct inode *inode; 320 struct device *dev; 321 int rc = -ENOMEM; 322 323 if (id < 0) 324 return ERR_PTR(-EINVAL); 325 326 dev_dax = kzalloc(sizeof(*dev_dax), GFP_KERNEL); 327 if (!dev_dax) 328 return ERR_PTR(-ENOMEM); 329 330 memcpy(&dev_dax->pgmap, pgmap, sizeof(*pgmap)); 331 332 /* 333 * No 'host' or dax_operations since there is no access to this 334 * device outside of mmap of the resulting character device. 335 */ 336 dax_dev = alloc_dax(dev_dax, NULL, NULL); 337 if (!dax_dev) 338 goto err; 339 340 /* a device_dax instance is dead while the driver is not attached */ 341 kill_dax(dax_dev); 342 343 /* from here on we're committed to teardown via dax_dev_release() */ 344 dev = &dev_dax->dev; 345 device_initialize(dev); 346 347 dev_dax->dax_dev = dax_dev; 348 dev_dax->region = dax_region; 349 kref_get(&dax_region->kref); 350 351 inode = dax_inode(dax_dev); 352 dev->devt = inode->i_rdev; 353 dev->bus = &dax_bus_type; 354 dev->parent = parent; 355 dev->groups = dax_attribute_groups; 356 dev->release = dev_dax_release; 357 dev_set_name(dev, "dax%d.%d", dax_region->id, id); 358 359 rc = device_add(dev); 360 if (rc) { 361 kill_dev_dax(dev_dax); 362 put_device(dev); 363 return ERR_PTR(rc); 364 } 365 366 rc = devm_add_action_or_reset(dax_region->dev, unregister_dev_dax, dev); 367 if (rc) 368 return ERR_PTR(rc); 369 370 return dev_dax; 371 372 err: 373 kfree(dev_dax); 374 375 return ERR_PTR(rc); 376 } 377 EXPORT_SYMBOL_GPL(devm_create_dev_dax); 378 379 static int match_always_count; 380 381 int __dax_driver_register(struct dax_device_driver *dax_drv, 382 struct module *module, const char *mod_name) 383 { 384 struct device_driver *drv = &dax_drv->drv; 385 int rc = 0; 386 387 INIT_LIST_HEAD(&dax_drv->ids); 388 drv->owner = module; 389 drv->name = mod_name; 390 drv->mod_name = mod_name; 391 drv->bus = &dax_bus_type; 392 393 /* there can only be one default driver */ 394 mutex_lock(&dax_bus_lock); 395 match_always_count += dax_drv->match_always; 396 if (match_always_count > 1) { 397 match_always_count--; 398 WARN_ON(1); 399 rc = -EINVAL; 400 } 401 mutex_unlock(&dax_bus_lock); 402 if (rc) 403 return rc; 404 return driver_register(drv); 405 } 406 EXPORT_SYMBOL_GPL(__dax_driver_register); 407 408 void dax_driver_unregister(struct dax_device_driver *dax_drv) 409 { 410 struct dax_id *dax_id, *_id; 411 412 mutex_lock(&dax_bus_lock); 413 match_always_count -= dax_drv->match_always; 414 list_for_each_entry_safe(dax_id, _id, &dax_drv->ids, list) { 415 list_del(&dax_id->list); 416 kfree(dax_id); 417 } 418 mutex_unlock(&dax_bus_lock); 419 } 420 EXPORT_SYMBOL_GPL(dax_driver_unregister); 421 422 int __init dax_bus_init(void) 423 { 424 return bus_register(&dax_bus_type); 425 } 426 427 void __exit dax_bus_exit(void) 428 { 429 bus_unregister(&dax_bus_type); 430 } 431