1// SPDX-License-Identifier: GPL-2.0 2/* 3 * dcssblk.c -- the S/390 block driver for dcss memory 4 * 5 * Authors: Carsten Otte, Stefan Weinhuber, Gerald Schaefer 6 */ 7 8#define KMSG_COMPONENT "dcssblk" 9#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt 10 11#include <linux/module.h> 12#include <linux/moduleparam.h> 13#include <linux/ctype.h> 14#include <linux/errno.h> 15#include <linux/init.h> 16#include <linux/slab.h> 17#include <linux/blkdev.h> 18#include <linux/completion.h> 19#include <linux/interrupt.h> 20#include <linux/pfn_t.h> 21#include <linux/uio.h> 22#include <linux/dax.h> 23#include <linux/io.h> 24#include <asm/extmem.h> 25 26#define DCSSBLK_NAME "dcssblk" 27#define DCSSBLK_MINORS_PER_DISK 1 28#define DCSSBLK_PARM_LEN 400 29#define DCSS_BUS_ID_SIZE 20 30 31static int dcssblk_open(struct gendisk *disk, blk_mode_t mode); 32static void dcssblk_release(struct gendisk *disk); 33static void dcssblk_submit_bio(struct bio *bio); 34static long dcssblk_dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, 35 long nr_pages, enum dax_access_mode mode, void **kaddr, 36 pfn_t *pfn); 37 38static char dcssblk_segments[DCSSBLK_PARM_LEN] = "\0"; 39 40static int dcssblk_major; 41static const struct block_device_operations dcssblk_devops = { 42 .owner = THIS_MODULE, 43 .submit_bio = dcssblk_submit_bio, 44 .open = dcssblk_open, 45 .release = dcssblk_release, 46}; 47 48static int dcssblk_dax_zero_page_range(struct dax_device *dax_dev, 49 pgoff_t pgoff, size_t nr_pages) 50{ 51 long rc; 52 void *kaddr; 53 54 rc = dax_direct_access(dax_dev, pgoff, nr_pages, DAX_ACCESS, 55 &kaddr, NULL); 56 if (rc < 0) 57 return dax_mem2blk_err(rc); 58 59 memset(kaddr, 0, nr_pages << PAGE_SHIFT); 60 dax_flush(dax_dev, kaddr, nr_pages << PAGE_SHIFT); 61 return 0; 62} 63 64static const struct dax_operations dcssblk_dax_ops = { 65 .direct_access = dcssblk_dax_direct_access, 66 .zero_page_range = dcssblk_dax_zero_page_range, 67}; 68 69struct dcssblk_dev_info { 70 struct list_head lh; 71 struct device dev; 72 char segment_name[DCSS_BUS_ID_SIZE]; 73 atomic_t use_count; 74 struct gendisk *gd; 75 unsigned long start; 76 unsigned long end; 77 int segment_type; 78 unsigned char save_pending; 79 unsigned char is_shared; 80 int num_of_segments; 81 struct list_head seg_list; 82 struct dax_device *dax_dev; 83}; 84 85struct segment_info { 86 struct list_head lh; 87 char segment_name[DCSS_BUS_ID_SIZE]; 88 unsigned long start; 89 unsigned long end; 90 int segment_type; 91}; 92 93static ssize_t dcssblk_add_store(struct device * dev, struct device_attribute *attr, const char * buf, 94 size_t count); 95static ssize_t dcssblk_remove_store(struct device * dev, struct device_attribute *attr, const char * buf, 96 size_t count); 97 98static DEVICE_ATTR(add, S_IWUSR, NULL, dcssblk_add_store); 99static DEVICE_ATTR(remove, S_IWUSR, NULL, dcssblk_remove_store); 100 101static struct device *dcssblk_root_dev; 102 103static LIST_HEAD(dcssblk_devices); 104static struct rw_semaphore dcssblk_devices_sem; 105 106/* 107 * release function for segment device. 108 */ 109static void 110dcssblk_release_segment(struct device *dev) 111{ 112 struct dcssblk_dev_info *dev_info; 113 struct segment_info *entry, *temp; 114 115 dev_info = container_of(dev, struct dcssblk_dev_info, dev); 116 list_for_each_entry_safe(entry, temp, &dev_info->seg_list, lh) { 117 list_del(&entry->lh); 118 kfree(entry); 119 } 120 kfree(dev_info); 121 module_put(THIS_MODULE); 122} 123 124/* 125 * get a minor number. needs to be called with 126 * down_write(&dcssblk_devices_sem) and the 127 * device needs to be enqueued before the semaphore is 128 * freed. 129 */ 130static int 131dcssblk_assign_free_minor(struct dcssblk_dev_info *dev_info) 132{ 133 int minor, found; 134 struct dcssblk_dev_info *entry; 135 136 if (dev_info == NULL) 137 return -EINVAL; 138 for (minor = 0; minor < (1<<MINORBITS); minor++) { 139 found = 0; 140 // test if minor available 141 list_for_each_entry(entry, &dcssblk_devices, lh) 142 if (minor == entry->gd->first_minor) 143 found++; 144 if (!found) break; // got unused minor 145 } 146 if (found) 147 return -EBUSY; 148 dev_info->gd->first_minor = minor; 149 return 0; 150} 151 152/* 153 * get the struct dcssblk_dev_info from dcssblk_devices 154 * for the given name. 155 * down_read(&dcssblk_devices_sem) must be held. 156 */ 157static struct dcssblk_dev_info * 158dcssblk_get_device_by_name(char *name) 159{ 160 struct dcssblk_dev_info *entry; 161 162 list_for_each_entry(entry, &dcssblk_devices, lh) { 163 if (!strcmp(name, entry->segment_name)) { 164 return entry; 165 } 166 } 167 return NULL; 168} 169 170/* 171 * get the struct segment_info from seg_list 172 * for the given name. 173 * down_read(&dcssblk_devices_sem) must be held. 174 */ 175static struct segment_info * 176dcssblk_get_segment_by_name(char *name) 177{ 178 struct dcssblk_dev_info *dev_info; 179 struct segment_info *entry; 180 181 list_for_each_entry(dev_info, &dcssblk_devices, lh) { 182 list_for_each_entry(entry, &dev_info->seg_list, lh) { 183 if (!strcmp(name, entry->segment_name)) 184 return entry; 185 } 186 } 187 return NULL; 188} 189 190/* 191 * get the highest address of the multi-segment block. 192 */ 193static unsigned long 194dcssblk_find_highest_addr(struct dcssblk_dev_info *dev_info) 195{ 196 unsigned long highest_addr; 197 struct segment_info *entry; 198 199 highest_addr = 0; 200 list_for_each_entry(entry, &dev_info->seg_list, lh) { 201 if (highest_addr < entry->end) 202 highest_addr = entry->end; 203 } 204 return highest_addr; 205} 206 207/* 208 * get the lowest address of the multi-segment block. 209 */ 210static unsigned long 211dcssblk_find_lowest_addr(struct dcssblk_dev_info *dev_info) 212{ 213 int set_first; 214 unsigned long lowest_addr; 215 struct segment_info *entry; 216 217 set_first = 0; 218 lowest_addr = 0; 219 list_for_each_entry(entry, &dev_info->seg_list, lh) { 220 if (set_first == 0) { 221 lowest_addr = entry->start; 222 set_first = 1; 223 } else { 224 if (lowest_addr > entry->start) 225 lowest_addr = entry->start; 226 } 227 } 228 return lowest_addr; 229} 230 231/* 232 * Check continuity of segments. 233 */ 234static int 235dcssblk_is_continuous(struct dcssblk_dev_info *dev_info) 236{ 237 int i, j, rc; 238 struct segment_info *sort_list, *entry, temp; 239 240 if (dev_info->num_of_segments <= 1) 241 return 0; 242 243 sort_list = kcalloc(dev_info->num_of_segments, 244 sizeof(struct segment_info), 245 GFP_KERNEL); 246 if (sort_list == NULL) 247 return -ENOMEM; 248 i = 0; 249 list_for_each_entry(entry, &dev_info->seg_list, lh) { 250 memcpy(&sort_list[i], entry, sizeof(struct segment_info)); 251 i++; 252 } 253 254 /* sort segments */ 255 for (i = 0; i < dev_info->num_of_segments; i++) 256 for (j = 0; j < dev_info->num_of_segments; j++) 257 if (sort_list[j].start > sort_list[i].start) { 258 memcpy(&temp, &sort_list[i], 259 sizeof(struct segment_info)); 260 memcpy(&sort_list[i], &sort_list[j], 261 sizeof(struct segment_info)); 262 memcpy(&sort_list[j], &temp, 263 sizeof(struct segment_info)); 264 } 265 266 /* check continuity */ 267 for (i = 0; i < dev_info->num_of_segments - 1; i++) { 268 if ((sort_list[i].end + 1) != sort_list[i+1].start) { 269 pr_err("Adjacent DCSSs %s and %s are not " 270 "contiguous\n", sort_list[i].segment_name, 271 sort_list[i+1].segment_name); 272 rc = -EINVAL; 273 goto out; 274 } 275 /* EN and EW are allowed in a block device */ 276 if (sort_list[i].segment_type != sort_list[i+1].segment_type) { 277 if (!(sort_list[i].segment_type & SEGMENT_EXCLUSIVE) || 278 (sort_list[i].segment_type == SEG_TYPE_ER) || 279 !(sort_list[i+1].segment_type & 280 SEGMENT_EXCLUSIVE) || 281 (sort_list[i+1].segment_type == SEG_TYPE_ER)) { 282 pr_err("DCSS %s and DCSS %s have " 283 "incompatible types\n", 284 sort_list[i].segment_name, 285 sort_list[i+1].segment_name); 286 rc = -EINVAL; 287 goto out; 288 } 289 } 290 } 291 rc = 0; 292out: 293 kfree(sort_list); 294 return rc; 295} 296 297/* 298 * Load a segment 299 */ 300static int 301dcssblk_load_segment(char *name, struct segment_info **seg_info) 302{ 303 int rc; 304 305 /* already loaded? */ 306 down_read(&dcssblk_devices_sem); 307 *seg_info = dcssblk_get_segment_by_name(name); 308 up_read(&dcssblk_devices_sem); 309 if (*seg_info != NULL) 310 return -EEXIST; 311 312 /* get a struct segment_info */ 313 *seg_info = kzalloc(sizeof(struct segment_info), GFP_KERNEL); 314 if (*seg_info == NULL) 315 return -ENOMEM; 316 317 strcpy((*seg_info)->segment_name, name); 318 319 /* load the segment */ 320 rc = segment_load(name, SEGMENT_SHARED, 321 &(*seg_info)->start, &(*seg_info)->end); 322 if (rc < 0) { 323 segment_warning(rc, (*seg_info)->segment_name); 324 kfree(*seg_info); 325 } else { 326 INIT_LIST_HEAD(&(*seg_info)->lh); 327 (*seg_info)->segment_type = rc; 328 } 329 return rc; 330} 331 332/* 333 * device attribute for switching shared/nonshared (exclusive) 334 * operation (show + store) 335 */ 336static ssize_t 337dcssblk_shared_show(struct device *dev, struct device_attribute *attr, char *buf) 338{ 339 struct dcssblk_dev_info *dev_info; 340 341 dev_info = container_of(dev, struct dcssblk_dev_info, dev); 342 return sprintf(buf, dev_info->is_shared ? "1\n" : "0\n"); 343} 344 345static ssize_t 346dcssblk_shared_store(struct device *dev, struct device_attribute *attr, const char *inbuf, size_t count) 347{ 348 struct dcssblk_dev_info *dev_info; 349 struct segment_info *entry, *temp; 350 int rc; 351 352 if ((count > 1) && (inbuf[1] != '\n') && (inbuf[1] != '\0')) 353 return -EINVAL; 354 down_write(&dcssblk_devices_sem); 355 dev_info = container_of(dev, struct dcssblk_dev_info, dev); 356 if (atomic_read(&dev_info->use_count)) { 357 rc = -EBUSY; 358 goto out; 359 } 360 if (inbuf[0] == '1') { 361 /* reload segments in shared mode */ 362 list_for_each_entry(entry, &dev_info->seg_list, lh) { 363 rc = segment_modify_shared(entry->segment_name, 364 SEGMENT_SHARED); 365 if (rc < 0) { 366 BUG_ON(rc == -EINVAL); 367 if (rc != -EAGAIN) 368 goto removeseg; 369 } 370 } 371 dev_info->is_shared = 1; 372 switch (dev_info->segment_type) { 373 case SEG_TYPE_SR: 374 case SEG_TYPE_ER: 375 case SEG_TYPE_SC: 376 set_disk_ro(dev_info->gd, 1); 377 } 378 } else if (inbuf[0] == '0') { 379 /* reload segments in exclusive mode */ 380 if (dev_info->segment_type == SEG_TYPE_SC) { 381 pr_err("DCSS %s is of type SC and cannot be " 382 "loaded as exclusive-writable\n", 383 dev_info->segment_name); 384 rc = -EINVAL; 385 goto out; 386 } 387 list_for_each_entry(entry, &dev_info->seg_list, lh) { 388 rc = segment_modify_shared(entry->segment_name, 389 SEGMENT_EXCLUSIVE); 390 if (rc < 0) { 391 BUG_ON(rc == -EINVAL); 392 if (rc != -EAGAIN) 393 goto removeseg; 394 } 395 } 396 dev_info->is_shared = 0; 397 set_disk_ro(dev_info->gd, 0); 398 } else { 399 rc = -EINVAL; 400 goto out; 401 } 402 rc = count; 403 goto out; 404 405removeseg: 406 pr_err("DCSS device %s is removed after a failed access mode " 407 "change\n", dev_info->segment_name); 408 temp = entry; 409 list_for_each_entry(entry, &dev_info->seg_list, lh) { 410 if (entry != temp) 411 segment_unload(entry->segment_name); 412 } 413 list_del(&dev_info->lh); 414 up_write(&dcssblk_devices_sem); 415 416 dax_remove_host(dev_info->gd); 417 kill_dax(dev_info->dax_dev); 418 put_dax(dev_info->dax_dev); 419 del_gendisk(dev_info->gd); 420 put_disk(dev_info->gd); 421 422 if (device_remove_file_self(dev, attr)) { 423 device_unregister(dev); 424 put_device(dev); 425 } 426 return rc; 427out: 428 up_write(&dcssblk_devices_sem); 429 return rc; 430} 431static DEVICE_ATTR(shared, S_IWUSR | S_IRUSR, dcssblk_shared_show, 432 dcssblk_shared_store); 433 434/* 435 * device attribute for save operation on current copy 436 * of the segment. If the segment is busy, saving will 437 * become pending until it gets released, which can be 438 * undone by storing a non-true value to this entry. 439 * (show + store) 440 */ 441static ssize_t 442dcssblk_save_show(struct device *dev, struct device_attribute *attr, char *buf) 443{ 444 struct dcssblk_dev_info *dev_info; 445 446 dev_info = container_of(dev, struct dcssblk_dev_info, dev); 447 return sprintf(buf, dev_info->save_pending ? "1\n" : "0\n"); 448} 449 450static ssize_t 451dcssblk_save_store(struct device *dev, struct device_attribute *attr, const char *inbuf, size_t count) 452{ 453 struct dcssblk_dev_info *dev_info; 454 struct segment_info *entry; 455 456 if ((count > 1) && (inbuf[1] != '\n') && (inbuf[1] != '\0')) 457 return -EINVAL; 458 dev_info = container_of(dev, struct dcssblk_dev_info, dev); 459 460 down_write(&dcssblk_devices_sem); 461 if (inbuf[0] == '1') { 462 if (atomic_read(&dev_info->use_count) == 0) { 463 // device is idle => we save immediately 464 pr_info("All DCSSs that map to device %s are " 465 "saved\n", dev_info->segment_name); 466 list_for_each_entry(entry, &dev_info->seg_list, lh) { 467 if (entry->segment_type == SEG_TYPE_EN || 468 entry->segment_type == SEG_TYPE_SN) 469 pr_warn("DCSS %s is of type SN or EN" 470 " and cannot be saved\n", 471 entry->segment_name); 472 else 473 segment_save(entry->segment_name); 474 } 475 } else { 476 // device is busy => we save it when it becomes 477 // idle in dcssblk_release 478 pr_info("Device %s is in use, its DCSSs will be " 479 "saved when it becomes idle\n", 480 dev_info->segment_name); 481 dev_info->save_pending = 1; 482 } 483 } else if (inbuf[0] == '0') { 484 if (dev_info->save_pending) { 485 // device is busy & the user wants to undo his save 486 // request 487 dev_info->save_pending = 0; 488 pr_info("A pending save request for device %s " 489 "has been canceled\n", 490 dev_info->segment_name); 491 } 492 } else { 493 up_write(&dcssblk_devices_sem); 494 return -EINVAL; 495 } 496 up_write(&dcssblk_devices_sem); 497 return count; 498} 499static DEVICE_ATTR(save, S_IWUSR | S_IRUSR, dcssblk_save_show, 500 dcssblk_save_store); 501 502/* 503 * device attribute for showing all segments in a device 504 */ 505static ssize_t 506dcssblk_seglist_show(struct device *dev, struct device_attribute *attr, 507 char *buf) 508{ 509 int i; 510 511 struct dcssblk_dev_info *dev_info; 512 struct segment_info *entry; 513 514 down_read(&dcssblk_devices_sem); 515 dev_info = container_of(dev, struct dcssblk_dev_info, dev); 516 i = 0; 517 buf[0] = '\0'; 518 list_for_each_entry(entry, &dev_info->seg_list, lh) { 519 strcpy(&buf[i], entry->segment_name); 520 i += strlen(entry->segment_name); 521 buf[i] = '\n'; 522 i++; 523 } 524 up_read(&dcssblk_devices_sem); 525 return i; 526} 527static DEVICE_ATTR(seglist, S_IRUSR, dcssblk_seglist_show, NULL); 528 529static struct attribute *dcssblk_dev_attrs[] = { 530 &dev_attr_shared.attr, 531 &dev_attr_save.attr, 532 &dev_attr_seglist.attr, 533 NULL, 534}; 535static struct attribute_group dcssblk_dev_attr_group = { 536 .attrs = dcssblk_dev_attrs, 537}; 538static const struct attribute_group *dcssblk_dev_attr_groups[] = { 539 &dcssblk_dev_attr_group, 540 NULL, 541}; 542 543/* 544 * device attribute for adding devices 545 */ 546static ssize_t 547dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) 548{ 549 int rc, i, j, num_of_segments; 550 struct dcssblk_dev_info *dev_info; 551 struct segment_info *seg_info, *temp; 552 char *local_buf; 553 unsigned long seg_byte_size; 554 555 dev_info = NULL; 556 seg_info = NULL; 557 if (dev != dcssblk_root_dev) { 558 rc = -EINVAL; 559 goto out_nobuf; 560 } 561 if ((count < 1) || (buf[0] == '\0') || (buf[0] == '\n')) { 562 rc = -ENAMETOOLONG; 563 goto out_nobuf; 564 } 565 566 local_buf = kmalloc(count + 1, GFP_KERNEL); 567 if (local_buf == NULL) { 568 rc = -ENOMEM; 569 goto out_nobuf; 570 } 571 572 /* 573 * parse input 574 */ 575 num_of_segments = 0; 576 for (i = 0; (i < count && (buf[i] != '\0') && (buf[i] != '\n')); i++) { 577 for (j = i; j < count && 578 (buf[j] != ':') && 579 (buf[j] != '\0') && 580 (buf[j] != '\n'); j++) { 581 local_buf[j-i] = toupper(buf[j]); 582 } 583 local_buf[j-i] = '\0'; 584 if (((j - i) == 0) || ((j - i) > 8)) { 585 rc = -ENAMETOOLONG; 586 goto seg_list_del; 587 } 588 589 rc = dcssblk_load_segment(local_buf, &seg_info); 590 if (rc < 0) 591 goto seg_list_del; 592 /* 593 * get a struct dcssblk_dev_info 594 */ 595 if (num_of_segments == 0) { 596 dev_info = kzalloc(sizeof(struct dcssblk_dev_info), 597 GFP_KERNEL); 598 if (dev_info == NULL) { 599 rc = -ENOMEM; 600 goto out; 601 } 602 strcpy(dev_info->segment_name, local_buf); 603 dev_info->segment_type = seg_info->segment_type; 604 INIT_LIST_HEAD(&dev_info->seg_list); 605 } 606 list_add_tail(&seg_info->lh, &dev_info->seg_list); 607 num_of_segments++; 608 i = j; 609 610 if ((buf[j] == '\0') || (buf[j] == '\n')) 611 break; 612 } 613 614 /* no trailing colon at the end of the input */ 615 if ((i > 0) && (buf[i-1] == ':')) { 616 rc = -ENAMETOOLONG; 617 goto seg_list_del; 618 } 619 strscpy(local_buf, buf, i + 1); 620 dev_info->num_of_segments = num_of_segments; 621 rc = dcssblk_is_continuous(dev_info); 622 if (rc < 0) 623 goto seg_list_del; 624 625 dev_info->start = dcssblk_find_lowest_addr(dev_info); 626 dev_info->end = dcssblk_find_highest_addr(dev_info); 627 628 dev_set_name(&dev_info->dev, "%s", dev_info->segment_name); 629 dev_info->dev.release = dcssblk_release_segment; 630 dev_info->dev.groups = dcssblk_dev_attr_groups; 631 INIT_LIST_HEAD(&dev_info->lh); 632 dev_info->gd = blk_alloc_disk(NUMA_NO_NODE); 633 if (dev_info->gd == NULL) { 634 rc = -ENOMEM; 635 goto seg_list_del; 636 } 637 dev_info->gd->major = dcssblk_major; 638 dev_info->gd->minors = DCSSBLK_MINORS_PER_DISK; 639 dev_info->gd->fops = &dcssblk_devops; 640 dev_info->gd->private_data = dev_info; 641 dev_info->gd->flags |= GENHD_FL_NO_PART; 642 blk_queue_logical_block_size(dev_info->gd->queue, 4096); 643 blk_queue_flag_set(QUEUE_FLAG_DAX, dev_info->gd->queue); 644 645 seg_byte_size = (dev_info->end - dev_info->start + 1); 646 set_capacity(dev_info->gd, seg_byte_size >> 9); // size in sectors 647 pr_info("Loaded %s with total size %lu bytes and capacity %lu " 648 "sectors\n", local_buf, seg_byte_size, seg_byte_size >> 9); 649 650 dev_info->save_pending = 0; 651 dev_info->is_shared = 1; 652 dev_info->dev.parent = dcssblk_root_dev; 653 654 /* 655 *get minor, add to list 656 */ 657 down_write(&dcssblk_devices_sem); 658 if (dcssblk_get_segment_by_name(local_buf)) { 659 rc = -EEXIST; 660 goto release_gd; 661 } 662 rc = dcssblk_assign_free_minor(dev_info); 663 if (rc) 664 goto release_gd; 665 sprintf(dev_info->gd->disk_name, "dcssblk%d", 666 dev_info->gd->first_minor); 667 list_add_tail(&dev_info->lh, &dcssblk_devices); 668 669 if (!try_module_get(THIS_MODULE)) { 670 rc = -ENODEV; 671 goto dev_list_del; 672 } 673 /* 674 * register the device 675 */ 676 rc = device_register(&dev_info->dev); 677 if (rc) 678 goto put_dev; 679 680 dev_info->dax_dev = alloc_dax(dev_info, &dcssblk_dax_ops); 681 if (IS_ERR(dev_info->dax_dev)) { 682 rc = PTR_ERR(dev_info->dax_dev); 683 dev_info->dax_dev = NULL; 684 goto put_dev; 685 } 686 set_dax_synchronous(dev_info->dax_dev); 687 rc = dax_add_host(dev_info->dax_dev, dev_info->gd); 688 if (rc) 689 goto out_dax; 690 691 get_device(&dev_info->dev); 692 rc = device_add_disk(&dev_info->dev, dev_info->gd, NULL); 693 if (rc) 694 goto out_dax_host; 695 696 switch (dev_info->segment_type) { 697 case SEG_TYPE_SR: 698 case SEG_TYPE_ER: 699 case SEG_TYPE_SC: 700 set_disk_ro(dev_info->gd,1); 701 break; 702 default: 703 set_disk_ro(dev_info->gd,0); 704 break; 705 } 706 up_write(&dcssblk_devices_sem); 707 rc = count; 708 goto out; 709 710out_dax_host: 711 put_device(&dev_info->dev); 712 dax_remove_host(dev_info->gd); 713out_dax: 714 kill_dax(dev_info->dax_dev); 715 put_dax(dev_info->dax_dev); 716put_dev: 717 list_del(&dev_info->lh); 718 put_disk(dev_info->gd); 719 list_for_each_entry(seg_info, &dev_info->seg_list, lh) { 720 segment_unload(seg_info->segment_name); 721 } 722 put_device(&dev_info->dev); 723 up_write(&dcssblk_devices_sem); 724 goto out; 725dev_list_del: 726 list_del(&dev_info->lh); 727release_gd: 728 put_disk(dev_info->gd); 729 up_write(&dcssblk_devices_sem); 730seg_list_del: 731 if (dev_info == NULL) 732 goto out; 733 list_for_each_entry_safe(seg_info, temp, &dev_info->seg_list, lh) { 734 list_del(&seg_info->lh); 735 segment_unload(seg_info->segment_name); 736 kfree(seg_info); 737 } 738 kfree(dev_info); 739out: 740 kfree(local_buf); 741out_nobuf: 742 return rc; 743} 744 745/* 746 * device attribute for removing devices 747 */ 748static ssize_t 749dcssblk_remove_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) 750{ 751 struct dcssblk_dev_info *dev_info; 752 struct segment_info *entry; 753 int rc, i; 754 char *local_buf; 755 756 if (dev != dcssblk_root_dev) { 757 return -EINVAL; 758 } 759 local_buf = kmalloc(count + 1, GFP_KERNEL); 760 if (local_buf == NULL) { 761 return -ENOMEM; 762 } 763 /* 764 * parse input 765 */ 766 for (i = 0; (i < count && (*(buf+i)!='\0') && (*(buf+i)!='\n')); i++) { 767 local_buf[i] = toupper(buf[i]); 768 } 769 local_buf[i] = '\0'; 770 if ((i == 0) || (i > 8)) { 771 rc = -ENAMETOOLONG; 772 goto out_buf; 773 } 774 775 down_write(&dcssblk_devices_sem); 776 dev_info = dcssblk_get_device_by_name(local_buf); 777 if (dev_info == NULL) { 778 up_write(&dcssblk_devices_sem); 779 pr_warn("Device %s cannot be removed because it is not a known device\n", 780 local_buf); 781 rc = -ENODEV; 782 goto out_buf; 783 } 784 if (atomic_read(&dev_info->use_count) != 0) { 785 up_write(&dcssblk_devices_sem); 786 pr_warn("Device %s cannot be removed while it is in use\n", 787 local_buf); 788 rc = -EBUSY; 789 goto out_buf; 790 } 791 792 list_del(&dev_info->lh); 793 /* unload all related segments */ 794 list_for_each_entry(entry, &dev_info->seg_list, lh) 795 segment_unload(entry->segment_name); 796 up_write(&dcssblk_devices_sem); 797 798 dax_remove_host(dev_info->gd); 799 kill_dax(dev_info->dax_dev); 800 put_dax(dev_info->dax_dev); 801 del_gendisk(dev_info->gd); 802 put_disk(dev_info->gd); 803 804 device_unregister(&dev_info->dev); 805 put_device(&dev_info->dev); 806 807 rc = count; 808out_buf: 809 kfree(local_buf); 810 return rc; 811} 812 813static int 814dcssblk_open(struct gendisk *disk, blk_mode_t mode) 815{ 816 struct dcssblk_dev_info *dev_info = disk->private_data; 817 int rc; 818 819 if (NULL == dev_info) { 820 rc = -ENODEV; 821 goto out; 822 } 823 atomic_inc(&dev_info->use_count); 824 rc = 0; 825out: 826 return rc; 827} 828 829static void 830dcssblk_release(struct gendisk *disk) 831{ 832 struct dcssblk_dev_info *dev_info = disk->private_data; 833 struct segment_info *entry; 834 835 if (!dev_info) { 836 WARN_ON(1); 837 return; 838 } 839 down_write(&dcssblk_devices_sem); 840 if (atomic_dec_and_test(&dev_info->use_count) 841 && (dev_info->save_pending)) { 842 pr_info("Device %s has become idle and is being saved " 843 "now\n", dev_info->segment_name); 844 list_for_each_entry(entry, &dev_info->seg_list, lh) { 845 if (entry->segment_type == SEG_TYPE_EN || 846 entry->segment_type == SEG_TYPE_SN) 847 pr_warn("DCSS %s is of type SN or EN and cannot" 848 " be saved\n", entry->segment_name); 849 else 850 segment_save(entry->segment_name); 851 } 852 dev_info->save_pending = 0; 853 } 854 up_write(&dcssblk_devices_sem); 855} 856 857static void 858dcssblk_submit_bio(struct bio *bio) 859{ 860 struct dcssblk_dev_info *dev_info; 861 struct bio_vec bvec; 862 struct bvec_iter iter; 863 unsigned long index; 864 void *page_addr; 865 unsigned long source_addr; 866 unsigned long bytes_done; 867 868 bytes_done = 0; 869 dev_info = bio->bi_bdev->bd_disk->private_data; 870 if (dev_info == NULL) 871 goto fail; 872 if (!IS_ALIGNED(bio->bi_iter.bi_sector, 8) || 873 !IS_ALIGNED(bio->bi_iter.bi_size, PAGE_SIZE)) 874 /* Request is not page-aligned. */ 875 goto fail; 876 /* verify data transfer direction */ 877 if (dev_info->is_shared) { 878 switch (dev_info->segment_type) { 879 case SEG_TYPE_SR: 880 case SEG_TYPE_ER: 881 case SEG_TYPE_SC: 882 /* cannot write to these segments */ 883 if (bio_data_dir(bio) == WRITE) { 884 pr_warn("Writing to %s failed because it is a read-only device\n", 885 dev_name(&dev_info->dev)); 886 goto fail; 887 } 888 } 889 } 890 891 index = (bio->bi_iter.bi_sector >> 3); 892 bio_for_each_segment(bvec, bio, iter) { 893 page_addr = bvec_virt(&bvec); 894 source_addr = dev_info->start + (index<<12) + bytes_done; 895 if (unlikely(!IS_ALIGNED((unsigned long)page_addr, PAGE_SIZE) || 896 !IS_ALIGNED(bvec.bv_len, PAGE_SIZE))) 897 // More paranoia. 898 goto fail; 899 if (bio_data_dir(bio) == READ) 900 memcpy(page_addr, __va(source_addr), bvec.bv_len); 901 else 902 memcpy(__va(source_addr), page_addr, bvec.bv_len); 903 bytes_done += bvec.bv_len; 904 } 905 bio_endio(bio); 906 return; 907fail: 908 bio_io_error(bio); 909} 910 911static long 912__dcssblk_direct_access(struct dcssblk_dev_info *dev_info, pgoff_t pgoff, 913 long nr_pages, void **kaddr, pfn_t *pfn) 914{ 915 resource_size_t offset = pgoff * PAGE_SIZE; 916 unsigned long dev_sz; 917 918 dev_sz = dev_info->end - dev_info->start + 1; 919 if (kaddr) 920 *kaddr = (void *) dev_info->start + offset; 921 if (pfn) 922 *pfn = __pfn_to_pfn_t(PFN_DOWN(dev_info->start + offset), 923 PFN_DEV|PFN_SPECIAL); 924 925 return (dev_sz - offset) / PAGE_SIZE; 926} 927 928static long 929dcssblk_dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, 930 long nr_pages, enum dax_access_mode mode, void **kaddr, 931 pfn_t *pfn) 932{ 933 struct dcssblk_dev_info *dev_info = dax_get_private(dax_dev); 934 935 return __dcssblk_direct_access(dev_info, pgoff, nr_pages, kaddr, pfn); 936} 937 938static void 939dcssblk_check_params(void) 940{ 941 int rc, i, j, k; 942 char buf[DCSSBLK_PARM_LEN + 1]; 943 struct dcssblk_dev_info *dev_info; 944 945 for (i = 0; (i < DCSSBLK_PARM_LEN) && (dcssblk_segments[i] != '\0'); 946 i++) { 947 for (j = i; (j < DCSSBLK_PARM_LEN) && 948 (dcssblk_segments[j] != ',') && 949 (dcssblk_segments[j] != '\0') && 950 (dcssblk_segments[j] != '('); j++) 951 { 952 buf[j-i] = dcssblk_segments[j]; 953 } 954 buf[j-i] = '\0'; 955 rc = dcssblk_add_store(dcssblk_root_dev, NULL, buf, j-i); 956 if ((rc >= 0) && (dcssblk_segments[j] == '(')) { 957 for (k = 0; (buf[k] != ':') && (buf[k] != '\0'); k++) 958 buf[k] = toupper(buf[k]); 959 buf[k] = '\0'; 960 if (!strncmp(&dcssblk_segments[j], "(local)", 7)) { 961 down_read(&dcssblk_devices_sem); 962 dev_info = dcssblk_get_device_by_name(buf); 963 up_read(&dcssblk_devices_sem); 964 if (dev_info) 965 dcssblk_shared_store(&dev_info->dev, 966 NULL, "0\n", 2); 967 } 968 } 969 while ((dcssblk_segments[j] != ',') && 970 (dcssblk_segments[j] != '\0')) 971 { 972 j++; 973 } 974 if (dcssblk_segments[j] == '\0') 975 break; 976 i = j; 977 } 978} 979 980/* 981 * The init/exit functions. 982 */ 983static void __exit 984dcssblk_exit(void) 985{ 986 root_device_unregister(dcssblk_root_dev); 987 unregister_blkdev(dcssblk_major, DCSSBLK_NAME); 988} 989 990static int __init 991dcssblk_init(void) 992{ 993 int rc; 994 995 dcssblk_root_dev = root_device_register("dcssblk"); 996 if (IS_ERR(dcssblk_root_dev)) 997 return PTR_ERR(dcssblk_root_dev); 998 rc = device_create_file(dcssblk_root_dev, &dev_attr_add); 999 if (rc) 1000 goto out_root; 1001 rc = device_create_file(dcssblk_root_dev, &dev_attr_remove); 1002 if (rc) 1003 goto out_root; 1004 rc = register_blkdev(0, DCSSBLK_NAME); 1005 if (rc < 0) 1006 goto out_root; 1007 dcssblk_major = rc; 1008 init_rwsem(&dcssblk_devices_sem); 1009 1010 dcssblk_check_params(); 1011 return 0; 1012 1013out_root: 1014 root_device_unregister(dcssblk_root_dev); 1015 1016 return rc; 1017} 1018 1019module_init(dcssblk_init); 1020module_exit(dcssblk_exit); 1021 1022module_param_string(segments, dcssblk_segments, DCSSBLK_PARM_LEN, 0444); 1023MODULE_PARM_DESC(segments, "Name of DCSS segment(s) to be loaded, " 1024 "comma-separated list, names in each set separated " 1025 "by commas are separated by colons, each set contains " 1026 "names of contiguous segments and each name max. 8 chars.\n" 1027 "Adding \"(local)\" to the end of each set equals echoing 0 " 1028 "to /sys/devices/dcssblk/<device name>/shared after loading " 1029 "the contiguous segments - \n" 1030 "e.g. segments=\"mydcss1,mydcss2:mydcss3,mydcss4(local)\""); 1031 1032MODULE_LICENSE("GPL"); 1033