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