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 <asm/extmem.h> 24 #include <asm/io.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 31 static int dcssblk_open(struct block_device *bdev, fmode_t mode); 32 static void dcssblk_release(struct gendisk *disk, fmode_t mode); 33 static void dcssblk_submit_bio(struct bio *bio); 34 static 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 38 static char dcssblk_segments[DCSSBLK_PARM_LEN] = "\0"; 39 40 static int dcssblk_major; 41 static 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 48 static 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 rc; 58 memset(kaddr, 0, nr_pages << PAGE_SHIFT); 59 dax_flush(dax_dev, kaddr, nr_pages << PAGE_SHIFT); 60 return 0; 61 } 62 63 static const struct dax_operations dcssblk_dax_ops = { 64 .direct_access = dcssblk_dax_direct_access, 65 .zero_page_range = dcssblk_dax_zero_page_range, 66 }; 67 68 struct dcssblk_dev_info { 69 struct list_head lh; 70 struct device dev; 71 char segment_name[DCSS_BUS_ID_SIZE]; 72 atomic_t use_count; 73 struct gendisk *gd; 74 unsigned long start; 75 unsigned long end; 76 int segment_type; 77 unsigned char save_pending; 78 unsigned char is_shared; 79 int num_of_segments; 80 struct list_head seg_list; 81 struct dax_device *dax_dev; 82 }; 83 84 struct segment_info { 85 struct list_head lh; 86 char segment_name[DCSS_BUS_ID_SIZE]; 87 unsigned long start; 88 unsigned long end; 89 int segment_type; 90 }; 91 92 static ssize_t dcssblk_add_store(struct device * dev, struct device_attribute *attr, const char * buf, 93 size_t count); 94 static ssize_t dcssblk_remove_store(struct device * dev, struct device_attribute *attr, const char * buf, 95 size_t count); 96 97 static DEVICE_ATTR(add, S_IWUSR, NULL, dcssblk_add_store); 98 static DEVICE_ATTR(remove, S_IWUSR, NULL, dcssblk_remove_store); 99 100 static struct device *dcssblk_root_dev; 101 102 static LIST_HEAD(dcssblk_devices); 103 static struct rw_semaphore dcssblk_devices_sem; 104 105 /* 106 * release function for segment device. 107 */ 108 static void 109 dcssblk_release_segment(struct device *dev) 110 { 111 struct dcssblk_dev_info *dev_info; 112 struct segment_info *entry, *temp; 113 114 dev_info = container_of(dev, struct dcssblk_dev_info, dev); 115 list_for_each_entry_safe(entry, temp, &dev_info->seg_list, lh) { 116 list_del(&entry->lh); 117 kfree(entry); 118 } 119 kfree(dev_info); 120 module_put(THIS_MODULE); 121 } 122 123 /* 124 * get a minor number. needs to be called with 125 * down_write(&dcssblk_devices_sem) and the 126 * device needs to be enqueued before the semaphore is 127 * freed. 128 */ 129 static int 130 dcssblk_assign_free_minor(struct dcssblk_dev_info *dev_info) 131 { 132 int minor, found; 133 struct dcssblk_dev_info *entry; 134 135 if (dev_info == NULL) 136 return -EINVAL; 137 for (minor = 0; minor < (1<<MINORBITS); minor++) { 138 found = 0; 139 // test if minor available 140 list_for_each_entry(entry, &dcssblk_devices, lh) 141 if (minor == entry->gd->first_minor) 142 found++; 143 if (!found) break; // got unused minor 144 } 145 if (found) 146 return -EBUSY; 147 dev_info->gd->first_minor = minor; 148 return 0; 149 } 150 151 /* 152 * get the struct dcssblk_dev_info from dcssblk_devices 153 * for the given name. 154 * down_read(&dcssblk_devices_sem) must be held. 155 */ 156 static struct dcssblk_dev_info * 157 dcssblk_get_device_by_name(char *name) 158 { 159 struct dcssblk_dev_info *entry; 160 161 list_for_each_entry(entry, &dcssblk_devices, lh) { 162 if (!strcmp(name, entry->segment_name)) { 163 return entry; 164 } 165 } 166 return NULL; 167 } 168 169 /* 170 * get the struct segment_info from seg_list 171 * for the given name. 172 * down_read(&dcssblk_devices_sem) must be held. 173 */ 174 static struct segment_info * 175 dcssblk_get_segment_by_name(char *name) 176 { 177 struct dcssblk_dev_info *dev_info; 178 struct segment_info *entry; 179 180 list_for_each_entry(dev_info, &dcssblk_devices, lh) { 181 list_for_each_entry(entry, &dev_info->seg_list, lh) { 182 if (!strcmp(name, entry->segment_name)) 183 return entry; 184 } 185 } 186 return NULL; 187 } 188 189 /* 190 * get the highest address of the multi-segment block. 191 */ 192 static unsigned long 193 dcssblk_find_highest_addr(struct dcssblk_dev_info *dev_info) 194 { 195 unsigned long highest_addr; 196 struct segment_info *entry; 197 198 highest_addr = 0; 199 list_for_each_entry(entry, &dev_info->seg_list, lh) { 200 if (highest_addr < entry->end) 201 highest_addr = entry->end; 202 } 203 return highest_addr; 204 } 205 206 /* 207 * get the lowest address of the multi-segment block. 208 */ 209 static unsigned long 210 dcssblk_find_lowest_addr(struct dcssblk_dev_info *dev_info) 211 { 212 int set_first; 213 unsigned long lowest_addr; 214 struct segment_info *entry; 215 216 set_first = 0; 217 lowest_addr = 0; 218 list_for_each_entry(entry, &dev_info->seg_list, lh) { 219 if (set_first == 0) { 220 lowest_addr = entry->start; 221 set_first = 1; 222 } else { 223 if (lowest_addr > entry->start) 224 lowest_addr = entry->start; 225 } 226 } 227 return lowest_addr; 228 } 229 230 /* 231 * Check continuity of segments. 232 */ 233 static int 234 dcssblk_is_continuous(struct dcssblk_dev_info *dev_info) 235 { 236 int i, j, rc; 237 struct segment_info *sort_list, *entry, temp; 238 239 if (dev_info->num_of_segments <= 1) 240 return 0; 241 242 sort_list = kcalloc(dev_info->num_of_segments, 243 sizeof(struct segment_info), 244 GFP_KERNEL); 245 if (sort_list == NULL) 246 return -ENOMEM; 247 i = 0; 248 list_for_each_entry(entry, &dev_info->seg_list, lh) { 249 memcpy(&sort_list[i], entry, sizeof(struct segment_info)); 250 i++; 251 } 252 253 /* sort segments */ 254 for (i = 0; i < dev_info->num_of_segments; i++) 255 for (j = 0; j < dev_info->num_of_segments; j++) 256 if (sort_list[j].start > sort_list[i].start) { 257 memcpy(&temp, &sort_list[i], 258 sizeof(struct segment_info)); 259 memcpy(&sort_list[i], &sort_list[j], 260 sizeof(struct segment_info)); 261 memcpy(&sort_list[j], &temp, 262 sizeof(struct segment_info)); 263 } 264 265 /* check continuity */ 266 for (i = 0; i < dev_info->num_of_segments - 1; i++) { 267 if ((sort_list[i].end + 1) != sort_list[i+1].start) { 268 pr_err("Adjacent DCSSs %s and %s are not " 269 "contiguous\n", sort_list[i].segment_name, 270 sort_list[i+1].segment_name); 271 rc = -EINVAL; 272 goto out; 273 } 274 /* EN and EW are allowed in a block device */ 275 if (sort_list[i].segment_type != sort_list[i+1].segment_type) { 276 if (!(sort_list[i].segment_type & SEGMENT_EXCLUSIVE) || 277 (sort_list[i].segment_type == SEG_TYPE_ER) || 278 !(sort_list[i+1].segment_type & 279 SEGMENT_EXCLUSIVE) || 280 (sort_list[i+1].segment_type == SEG_TYPE_ER)) { 281 pr_err("DCSS %s and DCSS %s have " 282 "incompatible types\n", 283 sort_list[i].segment_name, 284 sort_list[i+1].segment_name); 285 rc = -EINVAL; 286 goto out; 287 } 288 } 289 } 290 rc = 0; 291 out: 292 kfree(sort_list); 293 return rc; 294 } 295 296 /* 297 * Load a segment 298 */ 299 static int 300 dcssblk_load_segment(char *name, struct segment_info **seg_info) 301 { 302 int rc; 303 304 /* already loaded? */ 305 down_read(&dcssblk_devices_sem); 306 *seg_info = dcssblk_get_segment_by_name(name); 307 up_read(&dcssblk_devices_sem); 308 if (*seg_info != NULL) 309 return -EEXIST; 310 311 /* get a struct segment_info */ 312 *seg_info = kzalloc(sizeof(struct segment_info), GFP_KERNEL); 313 if (*seg_info == NULL) 314 return -ENOMEM; 315 316 strcpy((*seg_info)->segment_name, name); 317 318 /* load the segment */ 319 rc = segment_load(name, SEGMENT_SHARED, 320 &(*seg_info)->start, &(*seg_info)->end); 321 if (rc < 0) { 322 segment_warning(rc, (*seg_info)->segment_name); 323 kfree(*seg_info); 324 } else { 325 INIT_LIST_HEAD(&(*seg_info)->lh); 326 (*seg_info)->segment_type = rc; 327 } 328 return rc; 329 } 330 331 /* 332 * device attribute for switching shared/nonshared (exclusive) 333 * operation (show + store) 334 */ 335 static ssize_t 336 dcssblk_shared_show(struct device *dev, struct device_attribute *attr, char *buf) 337 { 338 struct dcssblk_dev_info *dev_info; 339 340 dev_info = container_of(dev, struct dcssblk_dev_info, dev); 341 return sprintf(buf, dev_info->is_shared ? "1\n" : "0\n"); 342 } 343 344 static ssize_t 345 dcssblk_shared_store(struct device *dev, struct device_attribute *attr, const char *inbuf, size_t count) 346 { 347 struct dcssblk_dev_info *dev_info; 348 struct segment_info *entry, *temp; 349 int rc; 350 351 if ((count > 1) && (inbuf[1] != '\n') && (inbuf[1] != '\0')) 352 return -EINVAL; 353 down_write(&dcssblk_devices_sem); 354 dev_info = container_of(dev, struct dcssblk_dev_info, dev); 355 if (atomic_read(&dev_info->use_count)) { 356 rc = -EBUSY; 357 goto out; 358 } 359 if (inbuf[0] == '1') { 360 /* reload segments in shared mode */ 361 list_for_each_entry(entry, &dev_info->seg_list, lh) { 362 rc = segment_modify_shared(entry->segment_name, 363 SEGMENT_SHARED); 364 if (rc < 0) { 365 BUG_ON(rc == -EINVAL); 366 if (rc != -EAGAIN) 367 goto removeseg; 368 } 369 } 370 dev_info->is_shared = 1; 371 switch (dev_info->segment_type) { 372 case SEG_TYPE_SR: 373 case SEG_TYPE_ER: 374 case SEG_TYPE_SC: 375 set_disk_ro(dev_info->gd, 1); 376 } 377 } else if (inbuf[0] == '0') { 378 /* reload segments in exclusive mode */ 379 if (dev_info->segment_type == SEG_TYPE_SC) { 380 pr_err("DCSS %s is of type SC and cannot be " 381 "loaded as exclusive-writable\n", 382 dev_info->segment_name); 383 rc = -EINVAL; 384 goto out; 385 } 386 list_for_each_entry(entry, &dev_info->seg_list, lh) { 387 rc = segment_modify_shared(entry->segment_name, 388 SEGMENT_EXCLUSIVE); 389 if (rc < 0) { 390 BUG_ON(rc == -EINVAL); 391 if (rc != -EAGAIN) 392 goto removeseg; 393 } 394 } 395 dev_info->is_shared = 0; 396 set_disk_ro(dev_info->gd, 0); 397 } else { 398 rc = -EINVAL; 399 goto out; 400 } 401 rc = count; 402 goto out; 403 404 removeseg: 405 pr_err("DCSS device %s is removed after a failed access mode " 406 "change\n", dev_info->segment_name); 407 temp = entry; 408 list_for_each_entry(entry, &dev_info->seg_list, lh) { 409 if (entry != temp) 410 segment_unload(entry->segment_name); 411 } 412 list_del(&dev_info->lh); 413 414 kill_dax(dev_info->dax_dev); 415 put_dax(dev_info->dax_dev); 416 del_gendisk(dev_info->gd); 417 put_disk(dev_info->gd); 418 up_write(&dcssblk_devices_sem); 419 420 if (device_remove_file_self(dev, attr)) { 421 device_unregister(dev); 422 put_device(dev); 423 } 424 return rc; 425 out: 426 up_write(&dcssblk_devices_sem); 427 return rc; 428 } 429 static DEVICE_ATTR(shared, S_IWUSR | S_IRUSR, dcssblk_shared_show, 430 dcssblk_shared_store); 431 432 /* 433 * device attribute for save operation on current copy 434 * of the segment. If the segment is busy, saving will 435 * become pending until it gets released, which can be 436 * undone by storing a non-true value to this entry. 437 * (show + store) 438 */ 439 static ssize_t 440 dcssblk_save_show(struct device *dev, struct device_attribute *attr, char *buf) 441 { 442 struct dcssblk_dev_info *dev_info; 443 444 dev_info = container_of(dev, struct dcssblk_dev_info, dev); 445 return sprintf(buf, dev_info->save_pending ? "1\n" : "0\n"); 446 } 447 448 static ssize_t 449 dcssblk_save_store(struct device *dev, struct device_attribute *attr, const char *inbuf, size_t count) 450 { 451 struct dcssblk_dev_info *dev_info; 452 struct segment_info *entry; 453 454 if ((count > 1) && (inbuf[1] != '\n') && (inbuf[1] != '\0')) 455 return -EINVAL; 456 dev_info = container_of(dev, struct dcssblk_dev_info, dev); 457 458 down_write(&dcssblk_devices_sem); 459 if (inbuf[0] == '1') { 460 if (atomic_read(&dev_info->use_count) == 0) { 461 // device is idle => we save immediately 462 pr_info("All DCSSs that map to device %s are " 463 "saved\n", dev_info->segment_name); 464 list_for_each_entry(entry, &dev_info->seg_list, lh) { 465 if (entry->segment_type == SEG_TYPE_EN || 466 entry->segment_type == SEG_TYPE_SN) 467 pr_warn("DCSS %s is of type SN or EN" 468 " and cannot be saved\n", 469 entry->segment_name); 470 else 471 segment_save(entry->segment_name); 472 } 473 } else { 474 // device is busy => we save it when it becomes 475 // idle in dcssblk_release 476 pr_info("Device %s is in use, its DCSSs will be " 477 "saved when it becomes idle\n", 478 dev_info->segment_name); 479 dev_info->save_pending = 1; 480 } 481 } else if (inbuf[0] == '0') { 482 if (dev_info->save_pending) { 483 // device is busy & the user wants to undo his save 484 // request 485 dev_info->save_pending = 0; 486 pr_info("A pending save request for device %s " 487 "has been canceled\n", 488 dev_info->segment_name); 489 } 490 } else { 491 up_write(&dcssblk_devices_sem); 492 return -EINVAL; 493 } 494 up_write(&dcssblk_devices_sem); 495 return count; 496 } 497 static DEVICE_ATTR(save, S_IWUSR | S_IRUSR, dcssblk_save_show, 498 dcssblk_save_store); 499 500 /* 501 * device attribute for showing all segments in a device 502 */ 503 static ssize_t 504 dcssblk_seglist_show(struct device *dev, struct device_attribute *attr, 505 char *buf) 506 { 507 int i; 508 509 struct dcssblk_dev_info *dev_info; 510 struct segment_info *entry; 511 512 down_read(&dcssblk_devices_sem); 513 dev_info = container_of(dev, struct dcssblk_dev_info, dev); 514 i = 0; 515 buf[0] = '\0'; 516 list_for_each_entry(entry, &dev_info->seg_list, lh) { 517 strcpy(&buf[i], entry->segment_name); 518 i += strlen(entry->segment_name); 519 buf[i] = '\n'; 520 i++; 521 } 522 up_read(&dcssblk_devices_sem); 523 return i; 524 } 525 static DEVICE_ATTR(seglist, S_IRUSR, dcssblk_seglist_show, NULL); 526 527 static struct attribute *dcssblk_dev_attrs[] = { 528 &dev_attr_shared.attr, 529 &dev_attr_save.attr, 530 &dev_attr_seglist.attr, 531 NULL, 532 }; 533 static struct attribute_group dcssblk_dev_attr_group = { 534 .attrs = dcssblk_dev_attrs, 535 }; 536 static const struct attribute_group *dcssblk_dev_attr_groups[] = { 537 &dcssblk_dev_attr_group, 538 NULL, 539 }; 540 541 /* 542 * device attribute for adding devices 543 */ 544 static ssize_t 545 dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) 546 { 547 int rc, i, j, num_of_segments; 548 struct dcssblk_dev_info *dev_info; 549 struct segment_info *seg_info, *temp; 550 char *local_buf; 551 unsigned long seg_byte_size; 552 553 dev_info = NULL; 554 seg_info = NULL; 555 if (dev != dcssblk_root_dev) { 556 rc = -EINVAL; 557 goto out_nobuf; 558 } 559 if ((count < 1) || (buf[0] == '\0') || (buf[0] == '\n')) { 560 rc = -ENAMETOOLONG; 561 goto out_nobuf; 562 } 563 564 local_buf = kmalloc(count + 1, GFP_KERNEL); 565 if (local_buf == NULL) { 566 rc = -ENOMEM; 567 goto out_nobuf; 568 } 569 570 /* 571 * parse input 572 */ 573 num_of_segments = 0; 574 for (i = 0; (i < count && (buf[i] != '\0') && (buf[i] != '\n')); i++) { 575 for (j = i; j < count && 576 (buf[j] != ':') && 577 (buf[j] != '\0') && 578 (buf[j] != '\n'); j++) { 579 local_buf[j-i] = toupper(buf[j]); 580 } 581 local_buf[j-i] = '\0'; 582 if (((j - i) == 0) || ((j - i) > 8)) { 583 rc = -ENAMETOOLONG; 584 goto seg_list_del; 585 } 586 587 rc = dcssblk_load_segment(local_buf, &seg_info); 588 if (rc < 0) 589 goto seg_list_del; 590 /* 591 * get a struct dcssblk_dev_info 592 */ 593 if (num_of_segments == 0) { 594 dev_info = kzalloc(sizeof(struct dcssblk_dev_info), 595 GFP_KERNEL); 596 if (dev_info == NULL) { 597 rc = -ENOMEM; 598 goto out; 599 } 600 strcpy(dev_info->segment_name, local_buf); 601 dev_info->segment_type = seg_info->segment_type; 602 INIT_LIST_HEAD(&dev_info->seg_list); 603 } 604 list_add_tail(&seg_info->lh, &dev_info->seg_list); 605 num_of_segments++; 606 i = j; 607 608 if ((buf[j] == '\0') || (buf[j] == '\n')) 609 break; 610 } 611 612 /* no trailing colon at the end of the input */ 613 if ((i > 0) && (buf[i-1] == ':')) { 614 rc = -ENAMETOOLONG; 615 goto seg_list_del; 616 } 617 strlcpy(local_buf, buf, i + 1); 618 dev_info->num_of_segments = num_of_segments; 619 rc = dcssblk_is_continuous(dev_info); 620 if (rc < 0) 621 goto seg_list_del; 622 623 dev_info->start = dcssblk_find_lowest_addr(dev_info); 624 dev_info->end = dcssblk_find_highest_addr(dev_info); 625 626 dev_set_name(&dev_info->dev, "%s", dev_info->segment_name); 627 dev_info->dev.release = dcssblk_release_segment; 628 dev_info->dev.groups = dcssblk_dev_attr_groups; 629 INIT_LIST_HEAD(&dev_info->lh); 630 dev_info->gd = blk_alloc_disk(NUMA_NO_NODE); 631 if (dev_info->gd == NULL) { 632 rc = -ENOMEM; 633 goto seg_list_del; 634 } 635 dev_info->gd->major = dcssblk_major; 636 dev_info->gd->minors = DCSSBLK_MINORS_PER_DISK; 637 dev_info->gd->fops = &dcssblk_devops; 638 dev_info->gd->private_data = dev_info; 639 blk_queue_logical_block_size(dev_info->gd->queue, 4096); 640 blk_queue_flag_set(QUEUE_FLAG_DAX, dev_info->gd->queue); 641 642 seg_byte_size = (dev_info->end - dev_info->start + 1); 643 set_capacity(dev_info->gd, seg_byte_size >> 9); // size in sectors 644 pr_info("Loaded %s with total size %lu bytes and capacity %lu " 645 "sectors\n", local_buf, seg_byte_size, seg_byte_size >> 9); 646 647 dev_info->save_pending = 0; 648 dev_info->is_shared = 1; 649 dev_info->dev.parent = dcssblk_root_dev; 650 651 /* 652 *get minor, add to list 653 */ 654 down_write(&dcssblk_devices_sem); 655 if (dcssblk_get_segment_by_name(local_buf)) { 656 rc = -EEXIST; 657 goto release_gd; 658 } 659 rc = dcssblk_assign_free_minor(dev_info); 660 if (rc) 661 goto release_gd; 662 sprintf(dev_info->gd->disk_name, "dcssblk%d", 663 dev_info->gd->first_minor); 664 list_add_tail(&dev_info->lh, &dcssblk_devices); 665 666 if (!try_module_get(THIS_MODULE)) { 667 rc = -ENODEV; 668 goto dev_list_del; 669 } 670 /* 671 * register the device 672 */ 673 rc = device_register(&dev_info->dev); 674 if (rc) 675 goto put_dev; 676 677 dev_info->dax_dev = alloc_dax(dev_info, &dcssblk_dax_ops); 678 if (IS_ERR(dev_info->dax_dev)) { 679 rc = PTR_ERR(dev_info->dax_dev); 680 dev_info->dax_dev = NULL; 681 goto put_dev; 682 } 683 set_dax_synchronous(dev_info->dax_dev); 684 rc = dax_add_host(dev_info->dax_dev, dev_info->gd); 685 if (rc) 686 goto out_dax; 687 688 get_device(&dev_info->dev); 689 rc = device_add_disk(&dev_info->dev, dev_info->gd, NULL); 690 if (rc) 691 goto out_dax_host; 692 693 switch (dev_info->segment_type) { 694 case SEG_TYPE_SR: 695 case SEG_TYPE_ER: 696 case SEG_TYPE_SC: 697 set_disk_ro(dev_info->gd,1); 698 break; 699 default: 700 set_disk_ro(dev_info->gd,0); 701 break; 702 } 703 up_write(&dcssblk_devices_sem); 704 rc = count; 705 goto out; 706 707 out_dax_host: 708 dax_remove_host(dev_info->gd); 709 out_dax: 710 put_device(&dev_info->dev); 711 kill_dax(dev_info->dax_dev); 712 put_dax(dev_info->dax_dev); 713 put_dev: 714 list_del(&dev_info->lh); 715 put_disk(dev_info->gd); 716 list_for_each_entry(seg_info, &dev_info->seg_list, lh) { 717 segment_unload(seg_info->segment_name); 718 } 719 put_device(&dev_info->dev); 720 up_write(&dcssblk_devices_sem); 721 goto out; 722 dev_list_del: 723 list_del(&dev_info->lh); 724 release_gd: 725 put_disk(dev_info->gd); 726 up_write(&dcssblk_devices_sem); 727 seg_list_del: 728 if (dev_info == NULL) 729 goto out; 730 list_for_each_entry_safe(seg_info, temp, &dev_info->seg_list, lh) { 731 list_del(&seg_info->lh); 732 segment_unload(seg_info->segment_name); 733 kfree(seg_info); 734 } 735 kfree(dev_info); 736 out: 737 kfree(local_buf); 738 out_nobuf: 739 return rc; 740 } 741 742 /* 743 * device attribute for removing devices 744 */ 745 static ssize_t 746 dcssblk_remove_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) 747 { 748 struct dcssblk_dev_info *dev_info; 749 struct segment_info *entry; 750 int rc, i; 751 char *local_buf; 752 753 if (dev != dcssblk_root_dev) { 754 return -EINVAL; 755 } 756 local_buf = kmalloc(count + 1, GFP_KERNEL); 757 if (local_buf == NULL) { 758 return -ENOMEM; 759 } 760 /* 761 * parse input 762 */ 763 for (i = 0; (i < count && (*(buf+i)!='\0') && (*(buf+i)!='\n')); i++) { 764 local_buf[i] = toupper(buf[i]); 765 } 766 local_buf[i] = '\0'; 767 if ((i == 0) || (i > 8)) { 768 rc = -ENAMETOOLONG; 769 goto out_buf; 770 } 771 772 down_write(&dcssblk_devices_sem); 773 dev_info = dcssblk_get_device_by_name(local_buf); 774 if (dev_info == NULL) { 775 up_write(&dcssblk_devices_sem); 776 pr_warn("Device %s cannot be removed because it is not a known device\n", 777 local_buf); 778 rc = -ENODEV; 779 goto out_buf; 780 } 781 if (atomic_read(&dev_info->use_count) != 0) { 782 up_write(&dcssblk_devices_sem); 783 pr_warn("Device %s cannot be removed while it is in use\n", 784 local_buf); 785 rc = -EBUSY; 786 goto out_buf; 787 } 788 789 list_del(&dev_info->lh); 790 kill_dax(dev_info->dax_dev); 791 put_dax(dev_info->dax_dev); 792 del_gendisk(dev_info->gd); 793 put_disk(dev_info->gd); 794 795 /* unload all related segments */ 796 list_for_each_entry(entry, &dev_info->seg_list, lh) 797 segment_unload(entry->segment_name); 798 799 up_write(&dcssblk_devices_sem); 800 801 device_unregister(&dev_info->dev); 802 put_device(&dev_info->dev); 803 804 rc = count; 805 out_buf: 806 kfree(local_buf); 807 return rc; 808 } 809 810 static int 811 dcssblk_open(struct block_device *bdev, fmode_t mode) 812 { 813 struct dcssblk_dev_info *dev_info; 814 int rc; 815 816 dev_info = bdev->bd_disk->private_data; 817 if (NULL == dev_info) { 818 rc = -ENODEV; 819 goto out; 820 } 821 atomic_inc(&dev_info->use_count); 822 rc = 0; 823 out: 824 return rc; 825 } 826 827 static void 828 dcssblk_release(struct gendisk *disk, fmode_t mode) 829 { 830 struct dcssblk_dev_info *dev_info = disk->private_data; 831 struct segment_info *entry; 832 833 if (!dev_info) { 834 WARN_ON(1); 835 return; 836 } 837 down_write(&dcssblk_devices_sem); 838 if (atomic_dec_and_test(&dev_info->use_count) 839 && (dev_info->save_pending)) { 840 pr_info("Device %s has become idle and is being saved " 841 "now\n", dev_info->segment_name); 842 list_for_each_entry(entry, &dev_info->seg_list, lh) { 843 if (entry->segment_type == SEG_TYPE_EN || 844 entry->segment_type == SEG_TYPE_SN) 845 pr_warn("DCSS %s is of type SN or EN and cannot" 846 " be saved\n", entry->segment_name); 847 else 848 segment_save(entry->segment_name); 849 } 850 dev_info->save_pending = 0; 851 } 852 up_write(&dcssblk_devices_sem); 853 } 854 855 static void 856 dcssblk_submit_bio(struct bio *bio) 857 { 858 struct dcssblk_dev_info *dev_info; 859 struct bio_vec bvec; 860 struct bvec_iter iter; 861 unsigned long index; 862 unsigned long page_addr; 863 unsigned long source_addr; 864 unsigned long bytes_done; 865 866 bio = bio_split_to_limits(bio); 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 ((bio->bi_iter.bi_sector & 7) != 0 || 873 (bio->bi_iter.bi_size & 4095) != 0) 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 = (unsigned long)bvec_virt(&bvec); 894 source_addr = dev_info->start + (index<<12) + bytes_done; 895 if (unlikely((page_addr & 4095) != 0) || (bvec.bv_len & 4095) != 0) 896 // More paranoia. 897 goto fail; 898 if (bio_data_dir(bio) == READ) { 899 memcpy((void*)page_addr, (void*)source_addr, 900 bvec.bv_len); 901 } else { 902 memcpy((void*)source_addr, (void*)page_addr, 903 bvec.bv_len); 904 } 905 bytes_done += bvec.bv_len; 906 } 907 bio_endio(bio); 908 return; 909 fail: 910 bio_io_error(bio); 911 } 912 913 static long 914 __dcssblk_direct_access(struct dcssblk_dev_info *dev_info, pgoff_t pgoff, 915 long nr_pages, void **kaddr, pfn_t *pfn) 916 { 917 resource_size_t offset = pgoff * PAGE_SIZE; 918 unsigned long dev_sz; 919 920 dev_sz = dev_info->end - dev_info->start + 1; 921 if (kaddr) 922 *kaddr = (void *) dev_info->start + offset; 923 if (pfn) 924 *pfn = __pfn_to_pfn_t(PFN_DOWN(dev_info->start + offset), 925 PFN_DEV|PFN_SPECIAL); 926 927 return (dev_sz - offset) / PAGE_SIZE; 928 } 929 930 static long 931 dcssblk_dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, 932 long nr_pages, enum dax_access_mode mode, void **kaddr, 933 pfn_t *pfn) 934 { 935 struct dcssblk_dev_info *dev_info = dax_get_private(dax_dev); 936 937 return __dcssblk_direct_access(dev_info, pgoff, nr_pages, kaddr, pfn); 938 } 939 940 static void 941 dcssblk_check_params(void) 942 { 943 int rc, i, j, k; 944 char buf[DCSSBLK_PARM_LEN + 1]; 945 struct dcssblk_dev_info *dev_info; 946 947 for (i = 0; (i < DCSSBLK_PARM_LEN) && (dcssblk_segments[i] != '\0'); 948 i++) { 949 for (j = i; (j < DCSSBLK_PARM_LEN) && 950 (dcssblk_segments[j] != ',') && 951 (dcssblk_segments[j] != '\0') && 952 (dcssblk_segments[j] != '('); j++) 953 { 954 buf[j-i] = dcssblk_segments[j]; 955 } 956 buf[j-i] = '\0'; 957 rc = dcssblk_add_store(dcssblk_root_dev, NULL, buf, j-i); 958 if ((rc >= 0) && (dcssblk_segments[j] == '(')) { 959 for (k = 0; (buf[k] != ':') && (buf[k] != '\0'); k++) 960 buf[k] = toupper(buf[k]); 961 buf[k] = '\0'; 962 if (!strncmp(&dcssblk_segments[j], "(local)", 7)) { 963 down_read(&dcssblk_devices_sem); 964 dev_info = dcssblk_get_device_by_name(buf); 965 up_read(&dcssblk_devices_sem); 966 if (dev_info) 967 dcssblk_shared_store(&dev_info->dev, 968 NULL, "0\n", 2); 969 } 970 } 971 while ((dcssblk_segments[j] != ',') && 972 (dcssblk_segments[j] != '\0')) 973 { 974 j++; 975 } 976 if (dcssblk_segments[j] == '\0') 977 break; 978 i = j; 979 } 980 } 981 982 /* 983 * The init/exit functions. 984 */ 985 static void __exit 986 dcssblk_exit(void) 987 { 988 root_device_unregister(dcssblk_root_dev); 989 unregister_blkdev(dcssblk_major, DCSSBLK_NAME); 990 } 991 992 static int __init 993 dcssblk_init(void) 994 { 995 int rc; 996 997 dcssblk_root_dev = root_device_register("dcssblk"); 998 if (IS_ERR(dcssblk_root_dev)) 999 return PTR_ERR(dcssblk_root_dev); 1000 rc = device_create_file(dcssblk_root_dev, &dev_attr_add); 1001 if (rc) 1002 goto out_root; 1003 rc = device_create_file(dcssblk_root_dev, &dev_attr_remove); 1004 if (rc) 1005 goto out_root; 1006 rc = register_blkdev(0, DCSSBLK_NAME); 1007 if (rc < 0) 1008 goto out_root; 1009 dcssblk_major = rc; 1010 init_rwsem(&dcssblk_devices_sem); 1011 1012 dcssblk_check_params(); 1013 return 0; 1014 1015 out_root: 1016 root_device_unregister(dcssblk_root_dev); 1017 1018 return rc; 1019 } 1020 1021 module_init(dcssblk_init); 1022 module_exit(dcssblk_exit); 1023 1024 module_param_string(segments, dcssblk_segments, DCSSBLK_PARM_LEN, 0444); 1025 MODULE_PARM_DESC(segments, "Name of DCSS segment(s) to be loaded, " 1026 "comma-separated list, names in each set separated " 1027 "by commas are separated by colons, each set contains " 1028 "names of contiguous segments and each name max. 8 chars.\n" 1029 "Adding \"(local)\" to the end of each set equals echoing 0 " 1030 "to /sys/devices/dcssblk/<device name>/shared after loading " 1031 "the contiguous segments - \n" 1032 "e.g. segments=\"mydcss1,mydcss2:mydcss3,mydcss4(local)\""); 1033 1034 MODULE_LICENSE("GPL"); 1035