1 /* 2 * Compressed RAM block device 3 * 4 * Copyright (C) 2008, 2009, 2010 Nitin Gupta 5 * 2012, 2013 Minchan Kim 6 * 7 * This code is released using a dual license strategy: BSD/GPL 8 * You can choose the licence that better fits your requirements. 9 * 10 * Released under the terms of 3-clause BSD License 11 * Released under the terms of GNU General Public License Version 2.0 12 * 13 */ 14 15 #define KMSG_COMPONENT "zram" 16 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt 17 18 #ifdef CONFIG_ZRAM_DEBUG 19 #define DEBUG 20 #endif 21 22 #include <linux/module.h> 23 #include <linux/kernel.h> 24 #include <linux/bio.h> 25 #include <linux/bitops.h> 26 #include <linux/blkdev.h> 27 #include <linux/buffer_head.h> 28 #include <linux/device.h> 29 #include <linux/genhd.h> 30 #include <linux/highmem.h> 31 #include <linux/slab.h> 32 #include <linux/lzo.h> 33 #include <linux/string.h> 34 #include <linux/vmalloc.h> 35 36 #include "zram_drv.h" 37 38 /* Globals */ 39 static int zram_major; 40 static struct zram *zram_devices; 41 42 /* Module params (documentation at end) */ 43 static unsigned int num_devices = 1; 44 45 static inline struct zram *dev_to_zram(struct device *dev) 46 { 47 return (struct zram *)dev_to_disk(dev)->private_data; 48 } 49 50 static ssize_t disksize_show(struct device *dev, 51 struct device_attribute *attr, char *buf) 52 { 53 struct zram *zram = dev_to_zram(dev); 54 55 return sprintf(buf, "%llu\n", zram->disksize); 56 } 57 58 static ssize_t initstate_show(struct device *dev, 59 struct device_attribute *attr, char *buf) 60 { 61 struct zram *zram = dev_to_zram(dev); 62 63 return sprintf(buf, "%u\n", zram->init_done); 64 } 65 66 static ssize_t num_reads_show(struct device *dev, 67 struct device_attribute *attr, char *buf) 68 { 69 struct zram *zram = dev_to_zram(dev); 70 71 return sprintf(buf, "%llu\n", 72 (u64)atomic64_read(&zram->stats.num_reads)); 73 } 74 75 static ssize_t num_writes_show(struct device *dev, 76 struct device_attribute *attr, char *buf) 77 { 78 struct zram *zram = dev_to_zram(dev); 79 80 return sprintf(buf, "%llu\n", 81 (u64)atomic64_read(&zram->stats.num_writes)); 82 } 83 84 static ssize_t invalid_io_show(struct device *dev, 85 struct device_attribute *attr, char *buf) 86 { 87 struct zram *zram = dev_to_zram(dev); 88 89 return sprintf(buf, "%llu\n", 90 (u64)atomic64_read(&zram->stats.invalid_io)); 91 } 92 93 static ssize_t notify_free_show(struct device *dev, 94 struct device_attribute *attr, char *buf) 95 { 96 struct zram *zram = dev_to_zram(dev); 97 98 return sprintf(buf, "%llu\n", 99 (u64)atomic64_read(&zram->stats.notify_free)); 100 } 101 102 static ssize_t zero_pages_show(struct device *dev, 103 struct device_attribute *attr, char *buf) 104 { 105 struct zram *zram = dev_to_zram(dev); 106 107 return sprintf(buf, "%u\n", atomic_read(&zram->stats.pages_zero)); 108 } 109 110 static ssize_t orig_data_size_show(struct device *dev, 111 struct device_attribute *attr, char *buf) 112 { 113 struct zram *zram = dev_to_zram(dev); 114 115 return sprintf(buf, "%llu\n", 116 (u64)(atomic_read(&zram->stats.pages_stored)) << PAGE_SHIFT); 117 } 118 119 static ssize_t compr_data_size_show(struct device *dev, 120 struct device_attribute *attr, char *buf) 121 { 122 struct zram *zram = dev_to_zram(dev); 123 124 return sprintf(buf, "%llu\n", 125 (u64)atomic64_read(&zram->stats.compr_size)); 126 } 127 128 static ssize_t mem_used_total_show(struct device *dev, 129 struct device_attribute *attr, char *buf) 130 { 131 u64 val = 0; 132 struct zram *zram = dev_to_zram(dev); 133 struct zram_meta *meta = zram->meta; 134 135 down_read(&zram->init_lock); 136 if (zram->init_done) 137 val = zs_get_total_size_bytes(meta->mem_pool); 138 up_read(&zram->init_lock); 139 140 return sprintf(buf, "%llu\n", val); 141 } 142 143 /* flag operations needs meta->tb_lock */ 144 static int zram_test_flag(struct zram_meta *meta, u32 index, 145 enum zram_pageflags flag) 146 { 147 return meta->table[index].flags & BIT(flag); 148 } 149 150 static void zram_set_flag(struct zram_meta *meta, u32 index, 151 enum zram_pageflags flag) 152 { 153 meta->table[index].flags |= BIT(flag); 154 } 155 156 static void zram_clear_flag(struct zram_meta *meta, u32 index, 157 enum zram_pageflags flag) 158 { 159 meta->table[index].flags &= ~BIT(flag); 160 } 161 162 static inline int is_partial_io(struct bio_vec *bvec) 163 { 164 return bvec->bv_len != PAGE_SIZE; 165 } 166 167 /* 168 * Check if request is within bounds and aligned on zram logical blocks. 169 */ 170 static inline int valid_io_request(struct zram *zram, struct bio *bio) 171 { 172 u64 start, end, bound; 173 174 /* unaligned request */ 175 if (unlikely(bio->bi_iter.bi_sector & 176 (ZRAM_SECTOR_PER_LOGICAL_BLOCK - 1))) 177 return 0; 178 if (unlikely(bio->bi_iter.bi_size & (ZRAM_LOGICAL_BLOCK_SIZE - 1))) 179 return 0; 180 181 start = bio->bi_iter.bi_sector; 182 end = start + (bio->bi_iter.bi_size >> SECTOR_SHIFT); 183 bound = zram->disksize >> SECTOR_SHIFT; 184 /* out of range range */ 185 if (unlikely(start >= bound || end > bound || start > end)) 186 return 0; 187 188 /* I/O request is valid */ 189 return 1; 190 } 191 192 static void zram_meta_free(struct zram_meta *meta) 193 { 194 zs_destroy_pool(meta->mem_pool); 195 kfree(meta->compress_workmem); 196 free_pages((unsigned long)meta->compress_buffer, 1); 197 vfree(meta->table); 198 kfree(meta); 199 } 200 201 static struct zram_meta *zram_meta_alloc(u64 disksize) 202 { 203 size_t num_pages; 204 struct zram_meta *meta = kmalloc(sizeof(*meta), GFP_KERNEL); 205 if (!meta) 206 goto out; 207 208 meta->compress_workmem = kzalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL); 209 if (!meta->compress_workmem) 210 goto free_meta; 211 212 meta->compress_buffer = 213 (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 1); 214 if (!meta->compress_buffer) { 215 pr_err("Error allocating compressor buffer space\n"); 216 goto free_workmem; 217 } 218 219 num_pages = disksize >> PAGE_SHIFT; 220 meta->table = vzalloc(num_pages * sizeof(*meta->table)); 221 if (!meta->table) { 222 pr_err("Error allocating zram address table\n"); 223 goto free_buffer; 224 } 225 226 meta->mem_pool = zs_create_pool(GFP_NOIO | __GFP_HIGHMEM); 227 if (!meta->mem_pool) { 228 pr_err("Error creating memory pool\n"); 229 goto free_table; 230 } 231 232 rwlock_init(&meta->tb_lock); 233 mutex_init(&meta->buffer_lock); 234 return meta; 235 236 free_table: 237 vfree(meta->table); 238 free_buffer: 239 free_pages((unsigned long)meta->compress_buffer, 1); 240 free_workmem: 241 kfree(meta->compress_workmem); 242 free_meta: 243 kfree(meta); 244 meta = NULL; 245 out: 246 return meta; 247 } 248 249 static void update_position(u32 *index, int *offset, struct bio_vec *bvec) 250 { 251 if (*offset + bvec->bv_len >= PAGE_SIZE) 252 (*index)++; 253 *offset = (*offset + bvec->bv_len) % PAGE_SIZE; 254 } 255 256 static int page_zero_filled(void *ptr) 257 { 258 unsigned int pos; 259 unsigned long *page; 260 261 page = (unsigned long *)ptr; 262 263 for (pos = 0; pos != PAGE_SIZE / sizeof(*page); pos++) { 264 if (page[pos]) 265 return 0; 266 } 267 268 return 1; 269 } 270 271 static void handle_zero_page(struct bio_vec *bvec) 272 { 273 struct page *page = bvec->bv_page; 274 void *user_mem; 275 276 user_mem = kmap_atomic(page); 277 if (is_partial_io(bvec)) 278 memset(user_mem + bvec->bv_offset, 0, bvec->bv_len); 279 else 280 clear_page(user_mem); 281 kunmap_atomic(user_mem); 282 283 flush_dcache_page(page); 284 } 285 286 /* NOTE: caller should hold meta->tb_lock with write-side */ 287 static void zram_free_page(struct zram *zram, size_t index) 288 { 289 struct zram_meta *meta = zram->meta; 290 unsigned long handle = meta->table[index].handle; 291 u16 size = meta->table[index].size; 292 293 if (unlikely(!handle)) { 294 /* 295 * No memory is allocated for zero filled pages. 296 * Simply clear zero page flag. 297 */ 298 if (zram_test_flag(meta, index, ZRAM_ZERO)) { 299 zram_clear_flag(meta, index, ZRAM_ZERO); 300 atomic_dec(&zram->stats.pages_zero); 301 } 302 return; 303 } 304 305 if (unlikely(size > max_zpage_size)) 306 atomic_dec(&zram->stats.bad_compress); 307 308 zs_free(meta->mem_pool, handle); 309 310 if (size <= PAGE_SIZE / 2) 311 atomic_dec(&zram->stats.good_compress); 312 313 atomic64_sub(meta->table[index].size, &zram->stats.compr_size); 314 atomic_dec(&zram->stats.pages_stored); 315 316 meta->table[index].handle = 0; 317 meta->table[index].size = 0; 318 } 319 320 static int zram_decompress_page(struct zram *zram, char *mem, u32 index) 321 { 322 int ret = LZO_E_OK; 323 size_t clen = PAGE_SIZE; 324 unsigned char *cmem; 325 struct zram_meta *meta = zram->meta; 326 unsigned long handle; 327 u16 size; 328 329 read_lock(&meta->tb_lock); 330 handle = meta->table[index].handle; 331 size = meta->table[index].size; 332 333 if (!handle || zram_test_flag(meta, index, ZRAM_ZERO)) { 334 read_unlock(&meta->tb_lock); 335 clear_page(mem); 336 return 0; 337 } 338 339 cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_RO); 340 if (size == PAGE_SIZE) 341 copy_page(mem, cmem); 342 else 343 ret = lzo1x_decompress_safe(cmem, size, mem, &clen); 344 zs_unmap_object(meta->mem_pool, handle); 345 read_unlock(&meta->tb_lock); 346 347 /* Should NEVER happen. Return bio error if it does. */ 348 if (unlikely(ret != LZO_E_OK)) { 349 pr_err("Decompression failed! err=%d, page=%u\n", ret, index); 350 atomic64_inc(&zram->stats.failed_reads); 351 return ret; 352 } 353 354 return 0; 355 } 356 357 static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec, 358 u32 index, int offset, struct bio *bio) 359 { 360 int ret; 361 struct page *page; 362 unsigned char *user_mem, *uncmem = NULL; 363 struct zram_meta *meta = zram->meta; 364 page = bvec->bv_page; 365 366 read_lock(&meta->tb_lock); 367 if (unlikely(!meta->table[index].handle) || 368 zram_test_flag(meta, index, ZRAM_ZERO)) { 369 read_unlock(&meta->tb_lock); 370 handle_zero_page(bvec); 371 return 0; 372 } 373 read_unlock(&meta->tb_lock); 374 375 if (is_partial_io(bvec)) 376 /* Use a temporary buffer to decompress the page */ 377 uncmem = kmalloc(PAGE_SIZE, GFP_NOIO); 378 379 user_mem = kmap_atomic(page); 380 if (!is_partial_io(bvec)) 381 uncmem = user_mem; 382 383 if (!uncmem) { 384 pr_info("Unable to allocate temp memory\n"); 385 ret = -ENOMEM; 386 goto out_cleanup; 387 } 388 389 ret = zram_decompress_page(zram, uncmem, index); 390 /* Should NEVER happen. Return bio error if it does. */ 391 if (unlikely(ret != LZO_E_OK)) 392 goto out_cleanup; 393 394 if (is_partial_io(bvec)) 395 memcpy(user_mem + bvec->bv_offset, uncmem + offset, 396 bvec->bv_len); 397 398 flush_dcache_page(page); 399 ret = 0; 400 out_cleanup: 401 kunmap_atomic(user_mem); 402 if (is_partial_io(bvec)) 403 kfree(uncmem); 404 return ret; 405 } 406 407 static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, 408 int offset) 409 { 410 int ret = 0; 411 size_t clen; 412 unsigned long handle; 413 struct page *page; 414 unsigned char *user_mem, *cmem, *src, *uncmem = NULL; 415 struct zram_meta *meta = zram->meta; 416 bool locked = false; 417 418 page = bvec->bv_page; 419 src = meta->compress_buffer; 420 421 if (is_partial_io(bvec)) { 422 /* 423 * This is a partial IO. We need to read the full page 424 * before to write the changes. 425 */ 426 uncmem = kmalloc(PAGE_SIZE, GFP_NOIO); 427 if (!uncmem) { 428 ret = -ENOMEM; 429 goto out; 430 } 431 ret = zram_decompress_page(zram, uncmem, index); 432 if (ret) 433 goto out; 434 } 435 436 mutex_lock(&meta->buffer_lock); 437 locked = true; 438 user_mem = kmap_atomic(page); 439 440 if (is_partial_io(bvec)) { 441 memcpy(uncmem + offset, user_mem + bvec->bv_offset, 442 bvec->bv_len); 443 kunmap_atomic(user_mem); 444 user_mem = NULL; 445 } else { 446 uncmem = user_mem; 447 } 448 449 if (page_zero_filled(uncmem)) { 450 kunmap_atomic(user_mem); 451 /* Free memory associated with this sector now. */ 452 write_lock(&zram->meta->tb_lock); 453 zram_free_page(zram, index); 454 zram_set_flag(meta, index, ZRAM_ZERO); 455 write_unlock(&zram->meta->tb_lock); 456 457 atomic_inc(&zram->stats.pages_zero); 458 ret = 0; 459 goto out; 460 } 461 462 ret = lzo1x_1_compress(uncmem, PAGE_SIZE, src, &clen, 463 meta->compress_workmem); 464 if (!is_partial_io(bvec)) { 465 kunmap_atomic(user_mem); 466 user_mem = NULL; 467 uncmem = NULL; 468 } 469 470 if (unlikely(ret != LZO_E_OK)) { 471 pr_err("Compression failed! err=%d\n", ret); 472 goto out; 473 } 474 475 if (unlikely(clen > max_zpage_size)) { 476 atomic_inc(&zram->stats.bad_compress); 477 clen = PAGE_SIZE; 478 src = NULL; 479 if (is_partial_io(bvec)) 480 src = uncmem; 481 } 482 483 handle = zs_malloc(meta->mem_pool, clen); 484 if (!handle) { 485 pr_info("Error allocating memory for compressed page: %u, size=%zu\n", 486 index, clen); 487 ret = -ENOMEM; 488 goto out; 489 } 490 cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_WO); 491 492 if ((clen == PAGE_SIZE) && !is_partial_io(bvec)) { 493 src = kmap_atomic(page); 494 copy_page(cmem, src); 495 kunmap_atomic(src); 496 } else { 497 memcpy(cmem, src, clen); 498 } 499 500 zs_unmap_object(meta->mem_pool, handle); 501 502 /* 503 * Free memory associated with this sector 504 * before overwriting unused sectors. 505 */ 506 write_lock(&zram->meta->tb_lock); 507 zram_free_page(zram, index); 508 509 meta->table[index].handle = handle; 510 meta->table[index].size = clen; 511 write_unlock(&zram->meta->tb_lock); 512 513 /* Update stats */ 514 atomic64_add(clen, &zram->stats.compr_size); 515 atomic_inc(&zram->stats.pages_stored); 516 if (clen <= PAGE_SIZE / 2) 517 atomic_inc(&zram->stats.good_compress); 518 519 out: 520 if (locked) 521 mutex_unlock(&meta->buffer_lock); 522 if (is_partial_io(bvec)) 523 kfree(uncmem); 524 525 if (ret) 526 atomic64_inc(&zram->stats.failed_writes); 527 return ret; 528 } 529 530 static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index, 531 int offset, struct bio *bio, int rw) 532 { 533 int ret; 534 535 if (rw == READ) 536 ret = zram_bvec_read(zram, bvec, index, offset, bio); 537 else 538 ret = zram_bvec_write(zram, bvec, index, offset); 539 540 return ret; 541 } 542 543 static void zram_reset_device(struct zram *zram, bool reset_capacity) 544 { 545 size_t index; 546 struct zram_meta *meta; 547 548 down_write(&zram->init_lock); 549 if (!zram->init_done) { 550 up_write(&zram->init_lock); 551 return; 552 } 553 554 meta = zram->meta; 555 zram->init_done = 0; 556 557 /* Free all pages that are still in this zram device */ 558 for (index = 0; index < zram->disksize >> PAGE_SHIFT; index++) { 559 unsigned long handle = meta->table[index].handle; 560 if (!handle) 561 continue; 562 563 zs_free(meta->mem_pool, handle); 564 } 565 566 zram_meta_free(zram->meta); 567 zram->meta = NULL; 568 /* Reset stats */ 569 memset(&zram->stats, 0, sizeof(zram->stats)); 570 571 zram->disksize = 0; 572 if (reset_capacity) 573 set_capacity(zram->disk, 0); 574 up_write(&zram->init_lock); 575 } 576 577 static void zram_init_device(struct zram *zram, struct zram_meta *meta) 578 { 579 if (zram->disksize > 2 * (totalram_pages << PAGE_SHIFT)) { 580 pr_info( 581 "There is little point creating a zram of greater than " 582 "twice the size of memory since we expect a 2:1 compression " 583 "ratio. Note that zram uses about 0.1%% of the size of " 584 "the disk when not in use so a huge zram is " 585 "wasteful.\n" 586 "\tMemory Size: %lu kB\n" 587 "\tSize you selected: %llu kB\n" 588 "Continuing anyway ...\n", 589 (totalram_pages << PAGE_SHIFT) >> 10, zram->disksize >> 10 590 ); 591 } 592 593 /* zram devices sort of resembles non-rotational disks */ 594 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, zram->disk->queue); 595 596 zram->meta = meta; 597 zram->init_done = 1; 598 599 pr_debug("Initialization done!\n"); 600 } 601 602 static ssize_t disksize_store(struct device *dev, 603 struct device_attribute *attr, const char *buf, size_t len) 604 { 605 u64 disksize; 606 struct zram_meta *meta; 607 struct zram *zram = dev_to_zram(dev); 608 609 disksize = memparse(buf, NULL); 610 if (!disksize) 611 return -EINVAL; 612 613 disksize = PAGE_ALIGN(disksize); 614 meta = zram_meta_alloc(disksize); 615 down_write(&zram->init_lock); 616 if (zram->init_done) { 617 up_write(&zram->init_lock); 618 zram_meta_free(meta); 619 pr_info("Cannot change disksize for initialized device\n"); 620 return -EBUSY; 621 } 622 623 zram->disksize = disksize; 624 set_capacity(zram->disk, zram->disksize >> SECTOR_SHIFT); 625 zram_init_device(zram, meta); 626 up_write(&zram->init_lock); 627 628 return len; 629 } 630 631 static ssize_t reset_store(struct device *dev, 632 struct device_attribute *attr, const char *buf, size_t len) 633 { 634 int ret; 635 unsigned short do_reset; 636 struct zram *zram; 637 struct block_device *bdev; 638 639 zram = dev_to_zram(dev); 640 bdev = bdget_disk(zram->disk, 0); 641 642 if (!bdev) 643 return -ENOMEM; 644 645 /* Do not reset an active device! */ 646 if (bdev->bd_holders) { 647 ret = -EBUSY; 648 goto out; 649 } 650 651 ret = kstrtou16(buf, 10, &do_reset); 652 if (ret) 653 goto out; 654 655 if (!do_reset) { 656 ret = -EINVAL; 657 goto out; 658 } 659 660 /* Make sure all pending I/O is finished */ 661 fsync_bdev(bdev); 662 bdput(bdev); 663 664 zram_reset_device(zram, true); 665 return len; 666 667 out: 668 bdput(bdev); 669 return ret; 670 } 671 672 static void __zram_make_request(struct zram *zram, struct bio *bio, int rw) 673 { 674 int offset; 675 u32 index; 676 struct bio_vec bvec; 677 struct bvec_iter iter; 678 679 switch (rw) { 680 case READ: 681 atomic64_inc(&zram->stats.num_reads); 682 break; 683 case WRITE: 684 atomic64_inc(&zram->stats.num_writes); 685 break; 686 } 687 688 index = bio->bi_iter.bi_sector >> SECTORS_PER_PAGE_SHIFT; 689 offset = (bio->bi_iter.bi_sector & 690 (SECTORS_PER_PAGE - 1)) << SECTOR_SHIFT; 691 692 bio_for_each_segment(bvec, bio, iter) { 693 int max_transfer_size = PAGE_SIZE - offset; 694 695 if (bvec.bv_len > max_transfer_size) { 696 /* 697 * zram_bvec_rw() can only make operation on a single 698 * zram page. Split the bio vector. 699 */ 700 struct bio_vec bv; 701 702 bv.bv_page = bvec.bv_page; 703 bv.bv_len = max_transfer_size; 704 bv.bv_offset = bvec.bv_offset; 705 706 if (zram_bvec_rw(zram, &bv, index, offset, bio, rw) < 0) 707 goto out; 708 709 bv.bv_len = bvec.bv_len - max_transfer_size; 710 bv.bv_offset += max_transfer_size; 711 if (zram_bvec_rw(zram, &bv, index+1, 0, bio, rw) < 0) 712 goto out; 713 } else 714 if (zram_bvec_rw(zram, &bvec, index, offset, bio, rw) 715 < 0) 716 goto out; 717 718 update_position(&index, &offset, &bvec); 719 } 720 721 set_bit(BIO_UPTODATE, &bio->bi_flags); 722 bio_endio(bio, 0); 723 return; 724 725 out: 726 bio_io_error(bio); 727 } 728 729 /* 730 * Handler function for all zram I/O requests. 731 */ 732 static void zram_make_request(struct request_queue *queue, struct bio *bio) 733 { 734 struct zram *zram = queue->queuedata; 735 736 down_read(&zram->init_lock); 737 if (unlikely(!zram->init_done)) 738 goto error; 739 740 if (!valid_io_request(zram, bio)) { 741 atomic64_inc(&zram->stats.invalid_io); 742 goto error; 743 } 744 745 __zram_make_request(zram, bio, bio_data_dir(bio)); 746 up_read(&zram->init_lock); 747 748 return; 749 750 error: 751 up_read(&zram->init_lock); 752 bio_io_error(bio); 753 } 754 755 static void zram_slot_free_notify(struct block_device *bdev, 756 unsigned long index) 757 { 758 struct zram *zram; 759 struct zram_meta *meta; 760 761 zram = bdev->bd_disk->private_data; 762 meta = zram->meta; 763 764 write_lock(&meta->tb_lock); 765 zram_free_page(zram, index); 766 write_unlock(&meta->tb_lock); 767 atomic64_inc(&zram->stats.notify_free); 768 } 769 770 static const struct block_device_operations zram_devops = { 771 .swap_slot_free_notify = zram_slot_free_notify, 772 .owner = THIS_MODULE 773 }; 774 775 static DEVICE_ATTR(disksize, S_IRUGO | S_IWUSR, 776 disksize_show, disksize_store); 777 static DEVICE_ATTR(initstate, S_IRUGO, initstate_show, NULL); 778 static DEVICE_ATTR(reset, S_IWUSR, NULL, reset_store); 779 static DEVICE_ATTR(num_reads, S_IRUGO, num_reads_show, NULL); 780 static DEVICE_ATTR(num_writes, S_IRUGO, num_writes_show, NULL); 781 static DEVICE_ATTR(invalid_io, S_IRUGO, invalid_io_show, NULL); 782 static DEVICE_ATTR(notify_free, S_IRUGO, notify_free_show, NULL); 783 static DEVICE_ATTR(zero_pages, S_IRUGO, zero_pages_show, NULL); 784 static DEVICE_ATTR(orig_data_size, S_IRUGO, orig_data_size_show, NULL); 785 static DEVICE_ATTR(compr_data_size, S_IRUGO, compr_data_size_show, NULL); 786 static DEVICE_ATTR(mem_used_total, S_IRUGO, mem_used_total_show, NULL); 787 788 static struct attribute *zram_disk_attrs[] = { 789 &dev_attr_disksize.attr, 790 &dev_attr_initstate.attr, 791 &dev_attr_reset.attr, 792 &dev_attr_num_reads.attr, 793 &dev_attr_num_writes.attr, 794 &dev_attr_invalid_io.attr, 795 &dev_attr_notify_free.attr, 796 &dev_attr_zero_pages.attr, 797 &dev_attr_orig_data_size.attr, 798 &dev_attr_compr_data_size.attr, 799 &dev_attr_mem_used_total.attr, 800 NULL, 801 }; 802 803 static struct attribute_group zram_disk_attr_group = { 804 .attrs = zram_disk_attrs, 805 }; 806 807 static int create_device(struct zram *zram, int device_id) 808 { 809 int ret = -ENOMEM; 810 811 init_rwsem(&zram->init_lock); 812 813 zram->queue = blk_alloc_queue(GFP_KERNEL); 814 if (!zram->queue) { 815 pr_err("Error allocating disk queue for device %d\n", 816 device_id); 817 goto out; 818 } 819 820 blk_queue_make_request(zram->queue, zram_make_request); 821 zram->queue->queuedata = zram; 822 823 /* gendisk structure */ 824 zram->disk = alloc_disk(1); 825 if (!zram->disk) { 826 pr_warn("Error allocating disk structure for device %d\n", 827 device_id); 828 goto out_free_queue; 829 } 830 831 zram->disk->major = zram_major; 832 zram->disk->first_minor = device_id; 833 zram->disk->fops = &zram_devops; 834 zram->disk->queue = zram->queue; 835 zram->disk->private_data = zram; 836 snprintf(zram->disk->disk_name, 16, "zram%d", device_id); 837 838 /* Actual capacity set using syfs (/sys/block/zram<id>/disksize */ 839 set_capacity(zram->disk, 0); 840 841 /* 842 * To ensure that we always get PAGE_SIZE aligned 843 * and n*PAGE_SIZED sized I/O requests. 844 */ 845 blk_queue_physical_block_size(zram->disk->queue, PAGE_SIZE); 846 blk_queue_logical_block_size(zram->disk->queue, 847 ZRAM_LOGICAL_BLOCK_SIZE); 848 blk_queue_io_min(zram->disk->queue, PAGE_SIZE); 849 blk_queue_io_opt(zram->disk->queue, PAGE_SIZE); 850 851 add_disk(zram->disk); 852 853 ret = sysfs_create_group(&disk_to_dev(zram->disk)->kobj, 854 &zram_disk_attr_group); 855 if (ret < 0) { 856 pr_warn("Error creating sysfs group"); 857 goto out_free_disk; 858 } 859 860 zram->init_done = 0; 861 return 0; 862 863 out_free_disk: 864 del_gendisk(zram->disk); 865 put_disk(zram->disk); 866 out_free_queue: 867 blk_cleanup_queue(zram->queue); 868 out: 869 return ret; 870 } 871 872 static void destroy_device(struct zram *zram) 873 { 874 sysfs_remove_group(&disk_to_dev(zram->disk)->kobj, 875 &zram_disk_attr_group); 876 877 del_gendisk(zram->disk); 878 put_disk(zram->disk); 879 880 blk_cleanup_queue(zram->queue); 881 } 882 883 static int __init zram_init(void) 884 { 885 int ret, dev_id; 886 887 if (num_devices > max_num_devices) { 888 pr_warn("Invalid value for num_devices: %u\n", 889 num_devices); 890 ret = -EINVAL; 891 goto out; 892 } 893 894 zram_major = register_blkdev(0, "zram"); 895 if (zram_major <= 0) { 896 pr_warn("Unable to get major number\n"); 897 ret = -EBUSY; 898 goto out; 899 } 900 901 /* Allocate the device array and initialize each one */ 902 zram_devices = kzalloc(num_devices * sizeof(struct zram), GFP_KERNEL); 903 if (!zram_devices) { 904 ret = -ENOMEM; 905 goto unregister; 906 } 907 908 for (dev_id = 0; dev_id < num_devices; dev_id++) { 909 ret = create_device(&zram_devices[dev_id], dev_id); 910 if (ret) 911 goto free_devices; 912 } 913 914 pr_info("Created %u device(s) ...\n", num_devices); 915 916 return 0; 917 918 free_devices: 919 while (dev_id) 920 destroy_device(&zram_devices[--dev_id]); 921 kfree(zram_devices); 922 unregister: 923 unregister_blkdev(zram_major, "zram"); 924 out: 925 return ret; 926 } 927 928 static void __exit zram_exit(void) 929 { 930 int i; 931 struct zram *zram; 932 933 for (i = 0; i < num_devices; i++) { 934 zram = &zram_devices[i]; 935 936 destroy_device(zram); 937 /* 938 * Shouldn't access zram->disk after destroy_device 939 * because destroy_device already released zram->disk. 940 */ 941 zram_reset_device(zram, false); 942 } 943 944 unregister_blkdev(zram_major, "zram"); 945 946 kfree(zram_devices); 947 pr_debug("Cleanup done!\n"); 948 } 949 950 module_init(zram_init); 951 module_exit(zram_exit); 952 953 module_param(num_devices, uint, 0); 954 MODULE_PARM_DESC(num_devices, "Number of zram devices"); 955 956 MODULE_LICENSE("Dual BSD/GPL"); 957 MODULE_AUTHOR("Nitin Gupta <ngupta@vflare.org>"); 958 MODULE_DESCRIPTION("Compressed RAM Block Device"); 959