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 31 static int dcssblk_open(struct gendisk *disk, blk_mode_t mode); 32 static void dcssblk_release(struct gendisk *disk); 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 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 64 static 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 69 struct 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 85 struct 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 93 static ssize_t dcssblk_add_store(struct device * dev, struct device_attribute *attr, const char * buf, 94 size_t count); 95 static ssize_t dcssblk_remove_store(struct device * dev, struct device_attribute *attr, const char * buf, 96 size_t count); 97 98 static DEVICE_ATTR(add, S_IWUSR, NULL, dcssblk_add_store); 99 static DEVICE_ATTR(remove, S_IWUSR, NULL, dcssblk_remove_store); 100 101 static struct device *dcssblk_root_dev; 102 103 static LIST_HEAD(dcssblk_devices); 104 static struct rw_semaphore dcssblk_devices_sem; 105 106 /* 107 * release function for segment device. 108 */ 109 static void 110 dcssblk_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 */ 130 static int 131 dcssblk_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 */ 157 static struct dcssblk_dev_info * 158 dcssblk_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 */ 175 static struct segment_info * 176 dcssblk_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 */ 193 static unsigned long 194 dcssblk_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 */ 210 static unsigned long 211 dcssblk_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 */ 234 static int 235 dcssblk_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; 292 out: 293 kfree(sort_list); 294 return rc; 295 } 296 297 /* 298 * Load a segment 299 */ 300 static int 301 dcssblk_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 */ 336 static ssize_t 337 dcssblk_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 } 344 345 static ssize_t 346 dcssblk_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; 404 405 removeseg: 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); 414 415 kill_dax(dev_info->dax_dev); 416 put_dax(dev_info->dax_dev); 417 del_gendisk(dev_info->gd); 418 put_disk(dev_info->gd); 419 up_write(&dcssblk_devices_sem); 420 421 if (device_remove_file_self(dev, attr)) { 422 device_unregister(dev); 423 put_device(dev); 424 } 425 return rc; 426 out: 427 up_write(&dcssblk_devices_sem); 428 return rc; 429 } 430 static DEVICE_ATTR(shared, S_IWUSR | S_IRUSR, dcssblk_shared_show, 431 dcssblk_shared_store); 432 433 /* 434 * device attribute for save operation on current copy 435 * of the segment. If the segment is busy, saving will 436 * become pending until it gets released, which can be 437 * undone by storing a non-true value to this entry. 438 * (show + store) 439 */ 440 static ssize_t 441 dcssblk_save_show(struct device *dev, struct device_attribute *attr, char *buf) 442 { 443 struct dcssblk_dev_info *dev_info; 444 445 dev_info = container_of(dev, struct dcssblk_dev_info, dev); 446 return sprintf(buf, dev_info->save_pending ? "1\n" : "0\n"); 447 } 448 449 static ssize_t 450 dcssblk_save_store(struct device *dev, struct device_attribute *attr, const char *inbuf, size_t count) 451 { 452 struct dcssblk_dev_info *dev_info; 453 struct segment_info *entry; 454 455 if ((count > 1) && (inbuf[1] != '\n') && (inbuf[1] != '\0')) 456 return -EINVAL; 457 dev_info = container_of(dev, struct dcssblk_dev_info, dev); 458 459 down_write(&dcssblk_devices_sem); 460 if (inbuf[0] == '1') { 461 if (atomic_read(&dev_info->use_count) == 0) { 462 // device is idle => we save immediately 463 pr_info("All DCSSs that map to device %s are " 464 "saved\n", dev_info->segment_name); 465 list_for_each_entry(entry, &dev_info->seg_list, lh) { 466 if (entry->segment_type == SEG_TYPE_EN || 467 entry->segment_type == SEG_TYPE_SN) 468 pr_warn("DCSS %s is of type SN or EN" 469 " and cannot be saved\n", 470 entry->segment_name); 471 else 472 segment_save(entry->segment_name); 473 } 474 } else { 475 // device is busy => we save it when it becomes 476 // idle in dcssblk_release 477 pr_info("Device %s is in use, its DCSSs will be " 478 "saved when it becomes idle\n", 479 dev_info->segment_name); 480 dev_info->save_pending = 1; 481 } 482 } else if (inbuf[0] == '0') { 483 if (dev_info->save_pending) { 484 // device is busy & the user wants to undo his save 485 // request 486 dev_info->save_pending = 0; 487 pr_info("A pending save request for device %s " 488 "has been canceled\n", 489 dev_info->segment_name); 490 } 491 } else { 492 up_write(&dcssblk_devices_sem); 493 return -EINVAL; 494 } 495 up_write(&dcssblk_devices_sem); 496 return count; 497 } 498 static DEVICE_ATTR(save, S_IWUSR | S_IRUSR, dcssblk_save_show, 499 dcssblk_save_store); 500 501 /* 502 * device attribute for showing all segments in a device 503 */ 504 static ssize_t 505 dcssblk_seglist_show(struct device *dev, struct device_attribute *attr, 506 char *buf) 507 { 508 int i; 509 510 struct dcssblk_dev_info *dev_info; 511 struct segment_info *entry; 512 513 down_read(&dcssblk_devices_sem); 514 dev_info = container_of(dev, struct dcssblk_dev_info, dev); 515 i = 0; 516 buf[0] = '\0'; 517 list_for_each_entry(entry, &dev_info->seg_list, lh) { 518 strcpy(&buf[i], entry->segment_name); 519 i += strlen(entry->segment_name); 520 buf[i] = '\n'; 521 i++; 522 } 523 up_read(&dcssblk_devices_sem); 524 return i; 525 } 526 static DEVICE_ATTR(seglist, S_IRUSR, dcssblk_seglist_show, NULL); 527 528 static struct attribute *dcssblk_dev_attrs[] = { 529 &dev_attr_shared.attr, 530 &dev_attr_save.attr, 531 &dev_attr_seglist.attr, 532 NULL, 533 }; 534 static struct attribute_group dcssblk_dev_attr_group = { 535 .attrs = dcssblk_dev_attrs, 536 }; 537 static const struct attribute_group *dcssblk_dev_attr_groups[] = { 538 &dcssblk_dev_attr_group, 539 NULL, 540 }; 541 542 /* 543 * device attribute for adding devices 544 */ 545 static ssize_t 546 dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) 547 { 548 int rc, i, j, num_of_segments; 549 struct dcssblk_dev_info *dev_info; 550 struct segment_info *seg_info, *temp; 551 char *local_buf; 552 unsigned long seg_byte_size; 553 554 dev_info = NULL; 555 seg_info = NULL; 556 if (dev != dcssblk_root_dev) { 557 rc = -EINVAL; 558 goto out_nobuf; 559 } 560 if ((count < 1) || (buf[0] == '\0') || (buf[0] == '\n')) { 561 rc = -ENAMETOOLONG; 562 goto out_nobuf; 563 } 564 565 local_buf = kmalloc(count + 1, GFP_KERNEL); 566 if (local_buf == NULL) { 567 rc = -ENOMEM; 568 goto out_nobuf; 569 } 570 571 /* 572 * parse input 573 */ 574 num_of_segments = 0; 575 for (i = 0; (i < count && (buf[i] != '\0') && (buf[i] != '\n')); i++) { 576 for (j = i; j < count && 577 (buf[j] != ':') && 578 (buf[j] != '\0') && 579 (buf[j] != '\n'); j++) { 580 local_buf[j-i] = toupper(buf[j]); 581 } 582 local_buf[j-i] = '\0'; 583 if (((j - i) == 0) || ((j - i) > 8)) { 584 rc = -ENAMETOOLONG; 585 goto seg_list_del; 586 } 587 588 rc = dcssblk_load_segment(local_buf, &seg_info); 589 if (rc < 0) 590 goto seg_list_del; 591 /* 592 * get a struct dcssblk_dev_info 593 */ 594 if (num_of_segments == 0) { 595 dev_info = kzalloc(sizeof(struct dcssblk_dev_info), 596 GFP_KERNEL); 597 if (dev_info == NULL) { 598 rc = -ENOMEM; 599 goto out; 600 } 601 strcpy(dev_info->segment_name, local_buf); 602 dev_info->segment_type = seg_info->segment_type; 603 INIT_LIST_HEAD(&dev_info->seg_list); 604 } 605 list_add_tail(&seg_info->lh, &dev_info->seg_list); 606 num_of_segments++; 607 i = j; 608 609 if ((buf[j] == '\0') || (buf[j] == '\n')) 610 break; 611 } 612 613 /* no trailing colon at the end of the input */ 614 if ((i > 0) && (buf[i-1] == ':')) { 615 rc = -ENAMETOOLONG; 616 goto seg_list_del; 617 } 618 strscpy(local_buf, buf, i + 1); 619 dev_info->num_of_segments = num_of_segments; 620 rc = dcssblk_is_continuous(dev_info); 621 if (rc < 0) 622 goto seg_list_del; 623 624 dev_info->start = dcssblk_find_lowest_addr(dev_info); 625 dev_info->end = dcssblk_find_highest_addr(dev_info); 626 627 dev_set_name(&dev_info->dev, "%s", dev_info->segment_name); 628 dev_info->dev.release = dcssblk_release_segment; 629 dev_info->dev.groups = dcssblk_dev_attr_groups; 630 INIT_LIST_HEAD(&dev_info->lh); 631 dev_info->gd = blk_alloc_disk(NUMA_NO_NODE); 632 if (dev_info->gd == NULL) { 633 rc = -ENOMEM; 634 goto seg_list_del; 635 } 636 dev_info->gd->major = dcssblk_major; 637 dev_info->gd->minors = DCSSBLK_MINORS_PER_DISK; 638 dev_info->gd->fops = &dcssblk_devops; 639 dev_info->gd->private_data = dev_info; 640 dev_info->gd->flags |= GENHD_FL_NO_PART; 641 blk_queue_logical_block_size(dev_info->gd->queue, 4096); 642 blk_queue_flag_set(QUEUE_FLAG_DAX, dev_info->gd->queue); 643 644 seg_byte_size = (dev_info->end - dev_info->start + 1); 645 set_capacity(dev_info->gd, seg_byte_size >> 9); // size in sectors 646 pr_info("Loaded %s with total size %lu bytes and capacity %lu " 647 "sectors\n", local_buf, seg_byte_size, seg_byte_size >> 9); 648 649 dev_info->save_pending = 0; 650 dev_info->is_shared = 1; 651 dev_info->dev.parent = dcssblk_root_dev; 652 653 /* 654 *get minor, add to list 655 */ 656 down_write(&dcssblk_devices_sem); 657 if (dcssblk_get_segment_by_name(local_buf)) { 658 rc = -EEXIST; 659 goto release_gd; 660 } 661 rc = dcssblk_assign_free_minor(dev_info); 662 if (rc) 663 goto release_gd; 664 sprintf(dev_info->gd->disk_name, "dcssblk%d", 665 dev_info->gd->first_minor); 666 list_add_tail(&dev_info->lh, &dcssblk_devices); 667 668 if (!try_module_get(THIS_MODULE)) { 669 rc = -ENODEV; 670 goto dev_list_del; 671 } 672 /* 673 * register the device 674 */ 675 rc = device_register(&dev_info->dev); 676 if (rc) 677 goto put_dev; 678 679 dev_info->dax_dev = alloc_dax(dev_info, &dcssblk_dax_ops); 680 if (IS_ERR(dev_info->dax_dev)) { 681 rc = PTR_ERR(dev_info->dax_dev); 682 dev_info->dax_dev = NULL; 683 goto put_dev; 684 } 685 set_dax_synchronous(dev_info->dax_dev); 686 rc = dax_add_host(dev_info->dax_dev, dev_info->gd); 687 if (rc) 688 goto out_dax; 689 690 get_device(&dev_info->dev); 691 rc = device_add_disk(&dev_info->dev, dev_info->gd, NULL); 692 if (rc) 693 goto out_dax_host; 694 695 switch (dev_info->segment_type) { 696 case SEG_TYPE_SR: 697 case SEG_TYPE_ER: 698 case SEG_TYPE_SC: 699 set_disk_ro(dev_info->gd,1); 700 break; 701 default: 702 set_disk_ro(dev_info->gd,0); 703 break; 704 } 705 up_write(&dcssblk_devices_sem); 706 rc = count; 707 goto out; 708 709 out_dax_host: 710 dax_remove_host(dev_info->gd); 711 out_dax: 712 put_device(&dev_info->dev); 713 kill_dax(dev_info->dax_dev); 714 put_dax(dev_info->dax_dev); 715 put_dev: 716 list_del(&dev_info->lh); 717 put_disk(dev_info->gd); 718 list_for_each_entry(seg_info, &dev_info->seg_list, lh) { 719 segment_unload(seg_info->segment_name); 720 } 721 put_device(&dev_info->dev); 722 up_write(&dcssblk_devices_sem); 723 goto out; 724 dev_list_del: 725 list_del(&dev_info->lh); 726 release_gd: 727 put_disk(dev_info->gd); 728 up_write(&dcssblk_devices_sem); 729 seg_list_del: 730 if (dev_info == NULL) 731 goto out; 732 list_for_each_entry_safe(seg_info, temp, &dev_info->seg_list, lh) { 733 list_del(&seg_info->lh); 734 segment_unload(seg_info->segment_name); 735 kfree(seg_info); 736 } 737 kfree(dev_info); 738 out: 739 kfree(local_buf); 740 out_nobuf: 741 return rc; 742 } 743 744 /* 745 * device attribute for removing devices 746 */ 747 static ssize_t 748 dcssblk_remove_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) 749 { 750 struct dcssblk_dev_info *dev_info; 751 struct segment_info *entry; 752 int rc, i; 753 char *local_buf; 754 755 if (dev != dcssblk_root_dev) { 756 return -EINVAL; 757 } 758 local_buf = kmalloc(count + 1, GFP_KERNEL); 759 if (local_buf == NULL) { 760 return -ENOMEM; 761 } 762 /* 763 * parse input 764 */ 765 for (i = 0; (i < count && (*(buf+i)!='\0') && (*(buf+i)!='\n')); i++) { 766 local_buf[i] = toupper(buf[i]); 767 } 768 local_buf[i] = '\0'; 769 if ((i == 0) || (i > 8)) { 770 rc = -ENAMETOOLONG; 771 goto out_buf; 772 } 773 774 down_write(&dcssblk_devices_sem); 775 dev_info = dcssblk_get_device_by_name(local_buf); 776 if (dev_info == NULL) { 777 up_write(&dcssblk_devices_sem); 778 pr_warn("Device %s cannot be removed because it is not a known device\n", 779 local_buf); 780 rc = -ENODEV; 781 goto out_buf; 782 } 783 if (atomic_read(&dev_info->use_count) != 0) { 784 up_write(&dcssblk_devices_sem); 785 pr_warn("Device %s cannot be removed while it is in use\n", 786 local_buf); 787 rc = -EBUSY; 788 goto out_buf; 789 } 790 791 list_del(&dev_info->lh); 792 kill_dax(dev_info->dax_dev); 793 put_dax(dev_info->dax_dev); 794 del_gendisk(dev_info->gd); 795 put_disk(dev_info->gd); 796 797 /* unload all related segments */ 798 list_for_each_entry(entry, &dev_info->seg_list, lh) 799 segment_unload(entry->segment_name); 800 801 up_write(&dcssblk_devices_sem); 802 803 device_unregister(&dev_info->dev); 804 put_device(&dev_info->dev); 805 806 rc = count; 807 out_buf: 808 kfree(local_buf); 809 return rc; 810 } 811 812 static int 813 dcssblk_open(struct gendisk *disk, blk_mode_t mode) 814 { 815 struct dcssblk_dev_info *dev_info = disk->private_data; 816 int rc; 817 818 if (NULL == dev_info) { 819 rc = -ENODEV; 820 goto out; 821 } 822 atomic_inc(&dev_info->use_count); 823 rc = 0; 824 out: 825 return rc; 826 } 827 828 static void 829 dcssblk_release(struct gendisk *disk) 830 { 831 struct dcssblk_dev_info *dev_info = disk->private_data; 832 struct segment_info *entry; 833 834 if (!dev_info) { 835 WARN_ON(1); 836 return; 837 } 838 down_write(&dcssblk_devices_sem); 839 if (atomic_dec_and_test(&dev_info->use_count) 840 && (dev_info->save_pending)) { 841 pr_info("Device %s has become idle and is being saved " 842 "now\n", dev_info->segment_name); 843 list_for_each_entry(entry, &dev_info->seg_list, lh) { 844 if (entry->segment_type == SEG_TYPE_EN || 845 entry->segment_type == SEG_TYPE_SN) 846 pr_warn("DCSS %s is of type SN or EN and cannot" 847 " be saved\n", entry->segment_name); 848 else 849 segment_save(entry->segment_name); 850 } 851 dev_info->save_pending = 0; 852 } 853 up_write(&dcssblk_devices_sem); 854 } 855 856 static void 857 dcssblk_submit_bio(struct bio *bio) 858 { 859 struct dcssblk_dev_info *dev_info; 860 struct bio_vec bvec; 861 struct bvec_iter iter; 862 unsigned long index; 863 unsigned long page_addr; 864 unsigned long source_addr; 865 unsigned long bytes_done; 866 867 bytes_done = 0; 868 dev_info = bio->bi_bdev->bd_disk->private_data; 869 if (dev_info == NULL) 870 goto fail; 871 if ((bio->bi_iter.bi_sector & 7) != 0 || 872 (bio->bi_iter.bi_size & 4095) != 0) 873 /* Request is not page-aligned. */ 874 goto fail; 875 /* verify data transfer direction */ 876 if (dev_info->is_shared) { 877 switch (dev_info->segment_type) { 878 case SEG_TYPE_SR: 879 case SEG_TYPE_ER: 880 case SEG_TYPE_SC: 881 /* cannot write to these segments */ 882 if (bio_data_dir(bio) == WRITE) { 883 pr_warn("Writing to %s failed because it is a read-only device\n", 884 dev_name(&dev_info->dev)); 885 goto fail; 886 } 887 } 888 } 889 890 index = (bio->bi_iter.bi_sector >> 3); 891 bio_for_each_segment(bvec, bio, iter) { 892 page_addr = (unsigned long)bvec_virt(&bvec); 893 source_addr = dev_info->start + (index<<12) + bytes_done; 894 if (unlikely((page_addr & 4095) != 0) || (bvec.bv_len & 4095) != 0) 895 // More paranoia. 896 goto fail; 897 if (bio_data_dir(bio) == READ) { 898 memcpy((void*)page_addr, (void*)source_addr, 899 bvec.bv_len); 900 } else { 901 memcpy((void*)source_addr, (void*)page_addr, 902 bvec.bv_len); 903 } 904 bytes_done += bvec.bv_len; 905 } 906 bio_endio(bio); 907 return; 908 fail: 909 bio_io_error(bio); 910 } 911 912 static long 913 __dcssblk_direct_access(struct dcssblk_dev_info *dev_info, pgoff_t pgoff, 914 long nr_pages, void **kaddr, pfn_t *pfn) 915 { 916 resource_size_t offset = pgoff * PAGE_SIZE; 917 unsigned long dev_sz; 918 919 dev_sz = dev_info->end - dev_info->start + 1; 920 if (kaddr) 921 *kaddr = (void *) dev_info->start + offset; 922 if (pfn) 923 *pfn = __pfn_to_pfn_t(PFN_DOWN(dev_info->start + offset), 924 PFN_DEV|PFN_SPECIAL); 925 926 return (dev_sz - offset) / PAGE_SIZE; 927 } 928 929 static long 930 dcssblk_dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, 931 long nr_pages, enum dax_access_mode mode, void **kaddr, 932 pfn_t *pfn) 933 { 934 struct dcssblk_dev_info *dev_info = dax_get_private(dax_dev); 935 936 return __dcssblk_direct_access(dev_info, pgoff, nr_pages, kaddr, pfn); 937 } 938 939 static void 940 dcssblk_check_params(void) 941 { 942 int rc, i, j, k; 943 char buf[DCSSBLK_PARM_LEN + 1]; 944 struct dcssblk_dev_info *dev_info; 945 946 for (i = 0; (i < DCSSBLK_PARM_LEN) && (dcssblk_segments[i] != '\0'); 947 i++) { 948 for (j = i; (j < DCSSBLK_PARM_LEN) && 949 (dcssblk_segments[j] != ',') && 950 (dcssblk_segments[j] != '\0') && 951 (dcssblk_segments[j] != '('); j++) 952 { 953 buf[j-i] = dcssblk_segments[j]; 954 } 955 buf[j-i] = '\0'; 956 rc = dcssblk_add_store(dcssblk_root_dev, NULL, buf, j-i); 957 if ((rc >= 0) && (dcssblk_segments[j] == '(')) { 958 for (k = 0; (buf[k] != ':') && (buf[k] != '\0'); k++) 959 buf[k] = toupper(buf[k]); 960 buf[k] = '\0'; 961 if (!strncmp(&dcssblk_segments[j], "(local)", 7)) { 962 down_read(&dcssblk_devices_sem); 963 dev_info = dcssblk_get_device_by_name(buf); 964 up_read(&dcssblk_devices_sem); 965 if (dev_info) 966 dcssblk_shared_store(&dev_info->dev, 967 NULL, "0\n", 2); 968 } 969 } 970 while ((dcssblk_segments[j] != ',') && 971 (dcssblk_segments[j] != '\0')) 972 { 973 j++; 974 } 975 if (dcssblk_segments[j] == '\0') 976 break; 977 i = j; 978 } 979 } 980 981 /* 982 * The init/exit functions. 983 */ 984 static void __exit 985 dcssblk_exit(void) 986 { 987 root_device_unregister(dcssblk_root_dev); 988 unregister_blkdev(dcssblk_major, DCSSBLK_NAME); 989 } 990 991 static int __init 992 dcssblk_init(void) 993 { 994 int rc; 995 996 dcssblk_root_dev = root_device_register("dcssblk"); 997 if (IS_ERR(dcssblk_root_dev)) 998 return PTR_ERR(dcssblk_root_dev); 999 rc = device_create_file(dcssblk_root_dev, &dev_attr_add); 1000 if (rc) 1001 goto out_root; 1002 rc = device_create_file(dcssblk_root_dev, &dev_attr_remove); 1003 if (rc) 1004 goto out_root; 1005 rc = register_blkdev(0, DCSSBLK_NAME); 1006 if (rc < 0) 1007 goto out_root; 1008 dcssblk_major = rc; 1009 init_rwsem(&dcssblk_devices_sem); 1010 1011 dcssblk_check_params(); 1012 return 0; 1013 1014 out_root: 1015 root_device_unregister(dcssblk_root_dev); 1016 1017 return rc; 1018 } 1019 1020 module_init(dcssblk_init); 1021 module_exit(dcssblk_exit); 1022 1023 module_param_string(segments, dcssblk_segments, DCSSBLK_PARM_LEN, 0444); 1024 MODULE_PARM_DESC(segments, "Name of DCSS segment(s) to be loaded, " 1025 "comma-separated list, names in each set separated " 1026 "by commas are separated by colons, each set contains " 1027 "names of contiguous segments and each name max. 8 chars.\n" 1028 "Adding \"(local)\" to the end of each set equals echoing 0 " 1029 "to /sys/devices/dcssblk/<device name>/shared after loading " 1030 "the contiguous segments - \n" 1031 "e.g. segments=\"mydcss1,mydcss2:mydcss3,mydcss4(local)\""); 1032 1033 MODULE_LICENSE("GPL"); 1034