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 #include <linux/module.h> 19 #include <linux/kernel.h> 20 #include <linux/bio.h> 21 #include <linux/bitops.h> 22 #include <linux/blkdev.h> 23 #include <linux/buffer_head.h> 24 #include <linux/device.h> 25 #include <linux/genhd.h> 26 #include <linux/highmem.h> 27 #include <linux/slab.h> 28 #include <linux/backing-dev.h> 29 #include <linux/string.h> 30 #include <linux/vmalloc.h> 31 #include <linux/err.h> 32 #include <linux/idr.h> 33 #include <linux/sysfs.h> 34 #include <linux/debugfs.h> 35 #include <linux/cpuhotplug.h> 36 37 #include "zram_drv.h" 38 39 static DEFINE_IDR(zram_index_idr); 40 /* idr index must be protected */ 41 static DEFINE_MUTEX(zram_index_mutex); 42 43 static int zram_major; 44 static const char *default_compressor = "lzo"; 45 46 /* Module params (documentation at end) */ 47 static unsigned int num_devices = 1; 48 /* 49 * Pages that compress to sizes equals or greater than this are stored 50 * uncompressed in memory. 51 */ 52 static size_t huge_class_size; 53 54 static void zram_free_page(struct zram *zram, size_t index); 55 56 static void zram_slot_lock(struct zram *zram, u32 index) 57 { 58 bit_spin_lock(ZRAM_LOCK, &zram->table[index].value); 59 } 60 61 static void zram_slot_unlock(struct zram *zram, u32 index) 62 { 63 bit_spin_unlock(ZRAM_LOCK, &zram->table[index].value); 64 } 65 66 static inline bool init_done(struct zram *zram) 67 { 68 return zram->disksize; 69 } 70 71 static inline bool zram_allocated(struct zram *zram, u32 index) 72 { 73 74 return (zram->table[index].value >> (ZRAM_FLAG_SHIFT + 1)) || 75 zram->table[index].handle; 76 } 77 78 static inline struct zram *dev_to_zram(struct device *dev) 79 { 80 return (struct zram *)dev_to_disk(dev)->private_data; 81 } 82 83 static unsigned long zram_get_handle(struct zram *zram, u32 index) 84 { 85 return zram->table[index].handle; 86 } 87 88 static void zram_set_handle(struct zram *zram, u32 index, unsigned long handle) 89 { 90 zram->table[index].handle = handle; 91 } 92 93 /* flag operations require table entry bit_spin_lock() being held */ 94 static bool zram_test_flag(struct zram *zram, u32 index, 95 enum zram_pageflags flag) 96 { 97 return zram->table[index].value & BIT(flag); 98 } 99 100 static void zram_set_flag(struct zram *zram, u32 index, 101 enum zram_pageflags flag) 102 { 103 zram->table[index].value |= BIT(flag); 104 } 105 106 static void zram_clear_flag(struct zram *zram, u32 index, 107 enum zram_pageflags flag) 108 { 109 zram->table[index].value &= ~BIT(flag); 110 } 111 112 static inline void zram_set_element(struct zram *zram, u32 index, 113 unsigned long element) 114 { 115 zram->table[index].element = element; 116 } 117 118 static unsigned long zram_get_element(struct zram *zram, u32 index) 119 { 120 return zram->table[index].element; 121 } 122 123 static size_t zram_get_obj_size(struct zram *zram, u32 index) 124 { 125 return zram->table[index].value & (BIT(ZRAM_FLAG_SHIFT) - 1); 126 } 127 128 static void zram_set_obj_size(struct zram *zram, 129 u32 index, size_t size) 130 { 131 unsigned long flags = zram->table[index].value >> ZRAM_FLAG_SHIFT; 132 133 zram->table[index].value = (flags << ZRAM_FLAG_SHIFT) | size; 134 } 135 136 #if PAGE_SIZE != 4096 137 static inline bool is_partial_io(struct bio_vec *bvec) 138 { 139 return bvec->bv_len != PAGE_SIZE; 140 } 141 #else 142 static inline bool is_partial_io(struct bio_vec *bvec) 143 { 144 return false; 145 } 146 #endif 147 148 /* 149 * Check if request is within bounds and aligned on zram logical blocks. 150 */ 151 static inline bool valid_io_request(struct zram *zram, 152 sector_t start, unsigned int size) 153 { 154 u64 end, bound; 155 156 /* unaligned request */ 157 if (unlikely(start & (ZRAM_SECTOR_PER_LOGICAL_BLOCK - 1))) 158 return false; 159 if (unlikely(size & (ZRAM_LOGICAL_BLOCK_SIZE - 1))) 160 return false; 161 162 end = start + (size >> SECTOR_SHIFT); 163 bound = zram->disksize >> SECTOR_SHIFT; 164 /* out of range range */ 165 if (unlikely(start >= bound || end > bound || start > end)) 166 return false; 167 168 /* I/O request is valid */ 169 return true; 170 } 171 172 static void update_position(u32 *index, int *offset, struct bio_vec *bvec) 173 { 174 *index += (*offset + bvec->bv_len) / PAGE_SIZE; 175 *offset = (*offset + bvec->bv_len) % PAGE_SIZE; 176 } 177 178 static inline void update_used_max(struct zram *zram, 179 const unsigned long pages) 180 { 181 unsigned long old_max, cur_max; 182 183 old_max = atomic_long_read(&zram->stats.max_used_pages); 184 185 do { 186 cur_max = old_max; 187 if (pages > cur_max) 188 old_max = atomic_long_cmpxchg( 189 &zram->stats.max_used_pages, cur_max, pages); 190 } while (old_max != cur_max); 191 } 192 193 static inline void zram_fill_page(void *ptr, unsigned long len, 194 unsigned long value) 195 { 196 WARN_ON_ONCE(!IS_ALIGNED(len, sizeof(unsigned long))); 197 memset_l(ptr, value, len / sizeof(unsigned long)); 198 } 199 200 static bool page_same_filled(void *ptr, unsigned long *element) 201 { 202 unsigned int pos; 203 unsigned long *page; 204 unsigned long val; 205 206 page = (unsigned long *)ptr; 207 val = page[0]; 208 209 for (pos = 1; pos < PAGE_SIZE / sizeof(*page); pos++) { 210 if (val != page[pos]) 211 return false; 212 } 213 214 *element = val; 215 216 return true; 217 } 218 219 static ssize_t initstate_show(struct device *dev, 220 struct device_attribute *attr, char *buf) 221 { 222 u32 val; 223 struct zram *zram = dev_to_zram(dev); 224 225 down_read(&zram->init_lock); 226 val = init_done(zram); 227 up_read(&zram->init_lock); 228 229 return scnprintf(buf, PAGE_SIZE, "%u\n", val); 230 } 231 232 static ssize_t disksize_show(struct device *dev, 233 struct device_attribute *attr, char *buf) 234 { 235 struct zram *zram = dev_to_zram(dev); 236 237 return scnprintf(buf, PAGE_SIZE, "%llu\n", zram->disksize); 238 } 239 240 static ssize_t mem_limit_store(struct device *dev, 241 struct device_attribute *attr, const char *buf, size_t len) 242 { 243 u64 limit; 244 char *tmp; 245 struct zram *zram = dev_to_zram(dev); 246 247 limit = memparse(buf, &tmp); 248 if (buf == tmp) /* no chars parsed, invalid input */ 249 return -EINVAL; 250 251 down_write(&zram->init_lock); 252 zram->limit_pages = PAGE_ALIGN(limit) >> PAGE_SHIFT; 253 up_write(&zram->init_lock); 254 255 return len; 256 } 257 258 static ssize_t mem_used_max_store(struct device *dev, 259 struct device_attribute *attr, const char *buf, size_t len) 260 { 261 int err; 262 unsigned long val; 263 struct zram *zram = dev_to_zram(dev); 264 265 err = kstrtoul(buf, 10, &val); 266 if (err || val != 0) 267 return -EINVAL; 268 269 down_read(&zram->init_lock); 270 if (init_done(zram)) { 271 atomic_long_set(&zram->stats.max_used_pages, 272 zs_get_total_pages(zram->mem_pool)); 273 } 274 up_read(&zram->init_lock); 275 276 return len; 277 } 278 279 #ifdef CONFIG_ZRAM_WRITEBACK 280 static bool zram_wb_enabled(struct zram *zram) 281 { 282 return zram->backing_dev; 283 } 284 285 static void reset_bdev(struct zram *zram) 286 { 287 struct block_device *bdev; 288 289 if (!zram_wb_enabled(zram)) 290 return; 291 292 bdev = zram->bdev; 293 if (zram->old_block_size) 294 set_blocksize(bdev, zram->old_block_size); 295 blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL); 296 /* hope filp_close flush all of IO */ 297 filp_close(zram->backing_dev, NULL); 298 zram->backing_dev = NULL; 299 zram->old_block_size = 0; 300 zram->bdev = NULL; 301 302 kvfree(zram->bitmap); 303 zram->bitmap = NULL; 304 } 305 306 static ssize_t backing_dev_show(struct device *dev, 307 struct device_attribute *attr, char *buf) 308 { 309 struct zram *zram = dev_to_zram(dev); 310 struct file *file = zram->backing_dev; 311 char *p; 312 ssize_t ret; 313 314 down_read(&zram->init_lock); 315 if (!zram_wb_enabled(zram)) { 316 memcpy(buf, "none\n", 5); 317 up_read(&zram->init_lock); 318 return 5; 319 } 320 321 p = file_path(file, buf, PAGE_SIZE - 1); 322 if (IS_ERR(p)) { 323 ret = PTR_ERR(p); 324 goto out; 325 } 326 327 ret = strlen(p); 328 memmove(buf, p, ret); 329 buf[ret++] = '\n'; 330 out: 331 up_read(&zram->init_lock); 332 return ret; 333 } 334 335 static ssize_t backing_dev_store(struct device *dev, 336 struct device_attribute *attr, const char *buf, size_t len) 337 { 338 char *file_name; 339 struct file *backing_dev = NULL; 340 struct inode *inode; 341 struct address_space *mapping; 342 unsigned int bitmap_sz, old_block_size = 0; 343 unsigned long nr_pages, *bitmap = NULL; 344 struct block_device *bdev = NULL; 345 int err; 346 struct zram *zram = dev_to_zram(dev); 347 348 file_name = kmalloc(PATH_MAX, GFP_KERNEL); 349 if (!file_name) 350 return -ENOMEM; 351 352 down_write(&zram->init_lock); 353 if (init_done(zram)) { 354 pr_info("Can't setup backing device for initialized device\n"); 355 err = -EBUSY; 356 goto out; 357 } 358 359 strlcpy(file_name, buf, len); 360 361 backing_dev = filp_open(file_name, O_RDWR|O_LARGEFILE, 0); 362 if (IS_ERR(backing_dev)) { 363 err = PTR_ERR(backing_dev); 364 backing_dev = NULL; 365 goto out; 366 } 367 368 mapping = backing_dev->f_mapping; 369 inode = mapping->host; 370 371 /* Support only block device in this moment */ 372 if (!S_ISBLK(inode->i_mode)) { 373 err = -ENOTBLK; 374 goto out; 375 } 376 377 bdev = bdgrab(I_BDEV(inode)); 378 err = blkdev_get(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL, zram); 379 if (err < 0) 380 goto out; 381 382 nr_pages = i_size_read(inode) >> PAGE_SHIFT; 383 bitmap_sz = BITS_TO_LONGS(nr_pages) * sizeof(long); 384 bitmap = kvzalloc(bitmap_sz, GFP_KERNEL); 385 if (!bitmap) { 386 err = -ENOMEM; 387 goto out; 388 } 389 390 old_block_size = block_size(bdev); 391 err = set_blocksize(bdev, PAGE_SIZE); 392 if (err) 393 goto out; 394 395 reset_bdev(zram); 396 spin_lock_init(&zram->bitmap_lock); 397 398 zram->old_block_size = old_block_size; 399 zram->bdev = bdev; 400 zram->backing_dev = backing_dev; 401 zram->bitmap = bitmap; 402 zram->nr_pages = nr_pages; 403 up_write(&zram->init_lock); 404 405 pr_info("setup backing device %s\n", file_name); 406 kfree(file_name); 407 408 return len; 409 out: 410 if (bitmap) 411 kvfree(bitmap); 412 413 if (bdev) 414 blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL); 415 416 if (backing_dev) 417 filp_close(backing_dev, NULL); 418 419 up_write(&zram->init_lock); 420 421 kfree(file_name); 422 423 return err; 424 } 425 426 static unsigned long get_entry_bdev(struct zram *zram) 427 { 428 unsigned long entry; 429 430 spin_lock(&zram->bitmap_lock); 431 /* skip 0 bit to confuse zram.handle = 0 */ 432 entry = find_next_zero_bit(zram->bitmap, zram->nr_pages, 1); 433 if (entry == zram->nr_pages) { 434 spin_unlock(&zram->bitmap_lock); 435 return 0; 436 } 437 438 set_bit(entry, zram->bitmap); 439 spin_unlock(&zram->bitmap_lock); 440 441 return entry; 442 } 443 444 static void put_entry_bdev(struct zram *zram, unsigned long entry) 445 { 446 int was_set; 447 448 spin_lock(&zram->bitmap_lock); 449 was_set = test_and_clear_bit(entry, zram->bitmap); 450 spin_unlock(&zram->bitmap_lock); 451 WARN_ON_ONCE(!was_set); 452 } 453 454 static void zram_page_end_io(struct bio *bio) 455 { 456 struct page *page = bio_first_page_all(bio); 457 458 page_endio(page, op_is_write(bio_op(bio)), 459 blk_status_to_errno(bio->bi_status)); 460 bio_put(bio); 461 } 462 463 /* 464 * Returns 1 if the submission is successful. 465 */ 466 static int read_from_bdev_async(struct zram *zram, struct bio_vec *bvec, 467 unsigned long entry, struct bio *parent) 468 { 469 struct bio *bio; 470 471 bio = bio_alloc(GFP_ATOMIC, 1); 472 if (!bio) 473 return -ENOMEM; 474 475 bio->bi_iter.bi_sector = entry * (PAGE_SIZE >> 9); 476 bio_set_dev(bio, zram->bdev); 477 if (!bio_add_page(bio, bvec->bv_page, bvec->bv_len, bvec->bv_offset)) { 478 bio_put(bio); 479 return -EIO; 480 } 481 482 if (!parent) { 483 bio->bi_opf = REQ_OP_READ; 484 bio->bi_end_io = zram_page_end_io; 485 } else { 486 bio->bi_opf = parent->bi_opf; 487 bio_chain(bio, parent); 488 } 489 490 submit_bio(bio); 491 return 1; 492 } 493 494 struct zram_work { 495 struct work_struct work; 496 struct zram *zram; 497 unsigned long entry; 498 struct bio *bio; 499 }; 500 501 #if PAGE_SIZE != 4096 502 static void zram_sync_read(struct work_struct *work) 503 { 504 struct bio_vec bvec; 505 struct zram_work *zw = container_of(work, struct zram_work, work); 506 struct zram *zram = zw->zram; 507 unsigned long entry = zw->entry; 508 struct bio *bio = zw->bio; 509 510 read_from_bdev_async(zram, &bvec, entry, bio); 511 } 512 513 /* 514 * Block layer want one ->make_request_fn to be active at a time 515 * so if we use chained IO with parent IO in same context, 516 * it's a deadlock. To avoid, it, it uses worker thread context. 517 */ 518 static int read_from_bdev_sync(struct zram *zram, struct bio_vec *bvec, 519 unsigned long entry, struct bio *bio) 520 { 521 struct zram_work work; 522 523 work.zram = zram; 524 work.entry = entry; 525 work.bio = bio; 526 527 INIT_WORK_ONSTACK(&work.work, zram_sync_read); 528 queue_work(system_unbound_wq, &work.work); 529 flush_work(&work.work); 530 destroy_work_on_stack(&work.work); 531 532 return 1; 533 } 534 #else 535 static int read_from_bdev_sync(struct zram *zram, struct bio_vec *bvec, 536 unsigned long entry, struct bio *bio) 537 { 538 WARN_ON(1); 539 return -EIO; 540 } 541 #endif 542 543 static int read_from_bdev(struct zram *zram, struct bio_vec *bvec, 544 unsigned long entry, struct bio *parent, bool sync) 545 { 546 if (sync) 547 return read_from_bdev_sync(zram, bvec, entry, parent); 548 else 549 return read_from_bdev_async(zram, bvec, entry, parent); 550 } 551 552 static int write_to_bdev(struct zram *zram, struct bio_vec *bvec, 553 u32 index, struct bio *parent, 554 unsigned long *pentry) 555 { 556 struct bio *bio; 557 unsigned long entry; 558 559 bio = bio_alloc(GFP_ATOMIC, 1); 560 if (!bio) 561 return -ENOMEM; 562 563 entry = get_entry_bdev(zram); 564 if (!entry) { 565 bio_put(bio); 566 return -ENOSPC; 567 } 568 569 bio->bi_iter.bi_sector = entry * (PAGE_SIZE >> 9); 570 bio_set_dev(bio, zram->bdev); 571 if (!bio_add_page(bio, bvec->bv_page, bvec->bv_len, 572 bvec->bv_offset)) { 573 bio_put(bio); 574 put_entry_bdev(zram, entry); 575 return -EIO; 576 } 577 578 if (!parent) { 579 bio->bi_opf = REQ_OP_WRITE | REQ_SYNC; 580 bio->bi_end_io = zram_page_end_io; 581 } else { 582 bio->bi_opf = parent->bi_opf; 583 bio_chain(bio, parent); 584 } 585 586 submit_bio(bio); 587 *pentry = entry; 588 589 return 0; 590 } 591 592 static void zram_wb_clear(struct zram *zram, u32 index) 593 { 594 unsigned long entry; 595 596 zram_clear_flag(zram, index, ZRAM_WB); 597 entry = zram_get_element(zram, index); 598 zram_set_element(zram, index, 0); 599 put_entry_bdev(zram, entry); 600 } 601 602 #else 603 static bool zram_wb_enabled(struct zram *zram) { return false; } 604 static inline void reset_bdev(struct zram *zram) {}; 605 static int write_to_bdev(struct zram *zram, struct bio_vec *bvec, 606 u32 index, struct bio *parent, 607 unsigned long *pentry) 608 609 { 610 return -EIO; 611 } 612 613 static int read_from_bdev(struct zram *zram, struct bio_vec *bvec, 614 unsigned long entry, struct bio *parent, bool sync) 615 { 616 return -EIO; 617 } 618 static void zram_wb_clear(struct zram *zram, u32 index) {} 619 #endif 620 621 #ifdef CONFIG_ZRAM_MEMORY_TRACKING 622 623 static struct dentry *zram_debugfs_root; 624 625 static void zram_debugfs_create(void) 626 { 627 zram_debugfs_root = debugfs_create_dir("zram", NULL); 628 } 629 630 static void zram_debugfs_destroy(void) 631 { 632 debugfs_remove_recursive(zram_debugfs_root); 633 } 634 635 static void zram_accessed(struct zram *zram, u32 index) 636 { 637 zram->table[index].ac_time = ktime_get_boottime(); 638 } 639 640 static void zram_reset_access(struct zram *zram, u32 index) 641 { 642 zram->table[index].ac_time = 0; 643 } 644 645 static ssize_t read_block_state(struct file *file, char __user *buf, 646 size_t count, loff_t *ppos) 647 { 648 char *kbuf; 649 ssize_t index, written = 0; 650 struct zram *zram = file->private_data; 651 unsigned long nr_pages = zram->disksize >> PAGE_SHIFT; 652 struct timespec64 ts; 653 654 kbuf = kvmalloc(count, GFP_KERNEL); 655 if (!kbuf) 656 return -ENOMEM; 657 658 down_read(&zram->init_lock); 659 if (!init_done(zram)) { 660 up_read(&zram->init_lock); 661 kvfree(kbuf); 662 return -EINVAL; 663 } 664 665 for (index = *ppos; index < nr_pages; index++) { 666 int copied; 667 668 zram_slot_lock(zram, index); 669 if (!zram_allocated(zram, index)) 670 goto next; 671 672 ts = ktime_to_timespec64(zram->table[index].ac_time); 673 copied = snprintf(kbuf + written, count, 674 "%12zd %12lld.%06lu %c%c%c\n", 675 index, (s64)ts.tv_sec, 676 ts.tv_nsec / NSEC_PER_USEC, 677 zram_test_flag(zram, index, ZRAM_SAME) ? 's' : '.', 678 zram_test_flag(zram, index, ZRAM_WB) ? 'w' : '.', 679 zram_test_flag(zram, index, ZRAM_HUGE) ? 'h' : '.'); 680 681 if (count < copied) { 682 zram_slot_unlock(zram, index); 683 break; 684 } 685 written += copied; 686 count -= copied; 687 next: 688 zram_slot_unlock(zram, index); 689 *ppos += 1; 690 } 691 692 up_read(&zram->init_lock); 693 if (copy_to_user(buf, kbuf, written)) 694 written = -EFAULT; 695 kvfree(kbuf); 696 697 return written; 698 } 699 700 static const struct file_operations proc_zram_block_state_op = { 701 .open = simple_open, 702 .read = read_block_state, 703 .llseek = default_llseek, 704 }; 705 706 static void zram_debugfs_register(struct zram *zram) 707 { 708 if (!zram_debugfs_root) 709 return; 710 711 zram->debugfs_dir = debugfs_create_dir(zram->disk->disk_name, 712 zram_debugfs_root); 713 debugfs_create_file("block_state", 0400, zram->debugfs_dir, 714 zram, &proc_zram_block_state_op); 715 } 716 717 static void zram_debugfs_unregister(struct zram *zram) 718 { 719 debugfs_remove_recursive(zram->debugfs_dir); 720 } 721 #else 722 static void zram_debugfs_create(void) {}; 723 static void zram_debugfs_destroy(void) {}; 724 static void zram_accessed(struct zram *zram, u32 index) {}; 725 static void zram_reset_access(struct zram *zram, u32 index) {}; 726 static void zram_debugfs_register(struct zram *zram) {}; 727 static void zram_debugfs_unregister(struct zram *zram) {}; 728 #endif 729 730 /* 731 * We switched to per-cpu streams and this attr is not needed anymore. 732 * However, we will keep it around for some time, because: 733 * a) we may revert per-cpu streams in the future 734 * b) it's visible to user space and we need to follow our 2 years 735 * retirement rule; but we already have a number of 'soon to be 736 * altered' attrs, so max_comp_streams need to wait for the next 737 * layoff cycle. 738 */ 739 static ssize_t max_comp_streams_show(struct device *dev, 740 struct device_attribute *attr, char *buf) 741 { 742 return scnprintf(buf, PAGE_SIZE, "%d\n", num_online_cpus()); 743 } 744 745 static ssize_t max_comp_streams_store(struct device *dev, 746 struct device_attribute *attr, const char *buf, size_t len) 747 { 748 return len; 749 } 750 751 static ssize_t comp_algorithm_show(struct device *dev, 752 struct device_attribute *attr, char *buf) 753 { 754 size_t sz; 755 struct zram *zram = dev_to_zram(dev); 756 757 down_read(&zram->init_lock); 758 sz = zcomp_available_show(zram->compressor, buf); 759 up_read(&zram->init_lock); 760 761 return sz; 762 } 763 764 static ssize_t comp_algorithm_store(struct device *dev, 765 struct device_attribute *attr, const char *buf, size_t len) 766 { 767 struct zram *zram = dev_to_zram(dev); 768 char compressor[ARRAY_SIZE(zram->compressor)]; 769 size_t sz; 770 771 strlcpy(compressor, buf, sizeof(compressor)); 772 /* ignore trailing newline */ 773 sz = strlen(compressor); 774 if (sz > 0 && compressor[sz - 1] == '\n') 775 compressor[sz - 1] = 0x00; 776 777 if (!zcomp_available_algorithm(compressor)) 778 return -EINVAL; 779 780 down_write(&zram->init_lock); 781 if (init_done(zram)) { 782 up_write(&zram->init_lock); 783 pr_info("Can't change algorithm for initialized device\n"); 784 return -EBUSY; 785 } 786 787 strcpy(zram->compressor, compressor); 788 up_write(&zram->init_lock); 789 return len; 790 } 791 792 static ssize_t compact_store(struct device *dev, 793 struct device_attribute *attr, const char *buf, size_t len) 794 { 795 struct zram *zram = dev_to_zram(dev); 796 797 down_read(&zram->init_lock); 798 if (!init_done(zram)) { 799 up_read(&zram->init_lock); 800 return -EINVAL; 801 } 802 803 zs_compact(zram->mem_pool); 804 up_read(&zram->init_lock); 805 806 return len; 807 } 808 809 static ssize_t io_stat_show(struct device *dev, 810 struct device_attribute *attr, char *buf) 811 { 812 struct zram *zram = dev_to_zram(dev); 813 ssize_t ret; 814 815 down_read(&zram->init_lock); 816 ret = scnprintf(buf, PAGE_SIZE, 817 "%8llu %8llu %8llu %8llu\n", 818 (u64)atomic64_read(&zram->stats.failed_reads), 819 (u64)atomic64_read(&zram->stats.failed_writes), 820 (u64)atomic64_read(&zram->stats.invalid_io), 821 (u64)atomic64_read(&zram->stats.notify_free)); 822 up_read(&zram->init_lock); 823 824 return ret; 825 } 826 827 static ssize_t mm_stat_show(struct device *dev, 828 struct device_attribute *attr, char *buf) 829 { 830 struct zram *zram = dev_to_zram(dev); 831 struct zs_pool_stats pool_stats; 832 u64 orig_size, mem_used = 0; 833 long max_used; 834 ssize_t ret; 835 836 memset(&pool_stats, 0x00, sizeof(struct zs_pool_stats)); 837 838 down_read(&zram->init_lock); 839 if (init_done(zram)) { 840 mem_used = zs_get_total_pages(zram->mem_pool); 841 zs_pool_stats(zram->mem_pool, &pool_stats); 842 } 843 844 orig_size = atomic64_read(&zram->stats.pages_stored); 845 max_used = atomic_long_read(&zram->stats.max_used_pages); 846 847 ret = scnprintf(buf, PAGE_SIZE, 848 "%8llu %8llu %8llu %8lu %8ld %8llu %8lu %8llu\n", 849 orig_size << PAGE_SHIFT, 850 (u64)atomic64_read(&zram->stats.compr_data_size), 851 mem_used << PAGE_SHIFT, 852 zram->limit_pages << PAGE_SHIFT, 853 max_used << PAGE_SHIFT, 854 (u64)atomic64_read(&zram->stats.same_pages), 855 pool_stats.pages_compacted, 856 (u64)atomic64_read(&zram->stats.huge_pages)); 857 up_read(&zram->init_lock); 858 859 return ret; 860 } 861 862 static ssize_t debug_stat_show(struct device *dev, 863 struct device_attribute *attr, char *buf) 864 { 865 int version = 1; 866 struct zram *zram = dev_to_zram(dev); 867 ssize_t ret; 868 869 down_read(&zram->init_lock); 870 ret = scnprintf(buf, PAGE_SIZE, 871 "version: %d\n%8llu\n", 872 version, 873 (u64)atomic64_read(&zram->stats.writestall)); 874 up_read(&zram->init_lock); 875 876 return ret; 877 } 878 879 static DEVICE_ATTR_RO(io_stat); 880 static DEVICE_ATTR_RO(mm_stat); 881 static DEVICE_ATTR_RO(debug_stat); 882 883 static void zram_meta_free(struct zram *zram, u64 disksize) 884 { 885 size_t num_pages = disksize >> PAGE_SHIFT; 886 size_t index; 887 888 /* Free all pages that are still in this zram device */ 889 for (index = 0; index < num_pages; index++) 890 zram_free_page(zram, index); 891 892 zs_destroy_pool(zram->mem_pool); 893 vfree(zram->table); 894 } 895 896 static bool zram_meta_alloc(struct zram *zram, u64 disksize) 897 { 898 size_t num_pages; 899 900 num_pages = disksize >> PAGE_SHIFT; 901 zram->table = vzalloc(array_size(num_pages, sizeof(*zram->table))); 902 if (!zram->table) 903 return false; 904 905 zram->mem_pool = zs_create_pool(zram->disk->disk_name); 906 if (!zram->mem_pool) { 907 vfree(zram->table); 908 return false; 909 } 910 911 if (!huge_class_size) 912 huge_class_size = zs_huge_class_size(zram->mem_pool); 913 return true; 914 } 915 916 /* 917 * To protect concurrent access to the same index entry, 918 * caller should hold this table index entry's bit_spinlock to 919 * indicate this index entry is accessing. 920 */ 921 static void zram_free_page(struct zram *zram, size_t index) 922 { 923 unsigned long handle; 924 925 zram_reset_access(zram, index); 926 927 if (zram_test_flag(zram, index, ZRAM_HUGE)) { 928 zram_clear_flag(zram, index, ZRAM_HUGE); 929 atomic64_dec(&zram->stats.huge_pages); 930 } 931 932 if (zram_wb_enabled(zram) && zram_test_flag(zram, index, ZRAM_WB)) { 933 zram_wb_clear(zram, index); 934 atomic64_dec(&zram->stats.pages_stored); 935 return; 936 } 937 938 /* 939 * No memory is allocated for same element filled pages. 940 * Simply clear same page flag. 941 */ 942 if (zram_test_flag(zram, index, ZRAM_SAME)) { 943 zram_clear_flag(zram, index, ZRAM_SAME); 944 zram_set_element(zram, index, 0); 945 atomic64_dec(&zram->stats.same_pages); 946 atomic64_dec(&zram->stats.pages_stored); 947 return; 948 } 949 950 handle = zram_get_handle(zram, index); 951 if (!handle) 952 return; 953 954 zs_free(zram->mem_pool, handle); 955 956 atomic64_sub(zram_get_obj_size(zram, index), 957 &zram->stats.compr_data_size); 958 atomic64_dec(&zram->stats.pages_stored); 959 960 zram_set_handle(zram, index, 0); 961 zram_set_obj_size(zram, index, 0); 962 } 963 964 static int __zram_bvec_read(struct zram *zram, struct page *page, u32 index, 965 struct bio *bio, bool partial_io) 966 { 967 int ret; 968 unsigned long handle; 969 unsigned int size; 970 void *src, *dst; 971 972 if (zram_wb_enabled(zram)) { 973 zram_slot_lock(zram, index); 974 if (zram_test_flag(zram, index, ZRAM_WB)) { 975 struct bio_vec bvec; 976 977 zram_slot_unlock(zram, index); 978 979 bvec.bv_page = page; 980 bvec.bv_len = PAGE_SIZE; 981 bvec.bv_offset = 0; 982 return read_from_bdev(zram, &bvec, 983 zram_get_element(zram, index), 984 bio, partial_io); 985 } 986 zram_slot_unlock(zram, index); 987 } 988 989 zram_slot_lock(zram, index); 990 handle = zram_get_handle(zram, index); 991 if (!handle || zram_test_flag(zram, index, ZRAM_SAME)) { 992 unsigned long value; 993 void *mem; 994 995 value = handle ? zram_get_element(zram, index) : 0; 996 mem = kmap_atomic(page); 997 zram_fill_page(mem, PAGE_SIZE, value); 998 kunmap_atomic(mem); 999 zram_slot_unlock(zram, index); 1000 return 0; 1001 } 1002 1003 size = zram_get_obj_size(zram, index); 1004 1005 src = zs_map_object(zram->mem_pool, handle, ZS_MM_RO); 1006 if (size == PAGE_SIZE) { 1007 dst = kmap_atomic(page); 1008 memcpy(dst, src, PAGE_SIZE); 1009 kunmap_atomic(dst); 1010 ret = 0; 1011 } else { 1012 struct zcomp_strm *zstrm = zcomp_stream_get(zram->comp); 1013 1014 dst = kmap_atomic(page); 1015 ret = zcomp_decompress(zstrm, src, size, dst); 1016 kunmap_atomic(dst); 1017 zcomp_stream_put(zram->comp); 1018 } 1019 zs_unmap_object(zram->mem_pool, handle); 1020 zram_slot_unlock(zram, index); 1021 1022 /* Should NEVER happen. Return bio error if it does. */ 1023 if (unlikely(ret)) 1024 pr_err("Decompression failed! err=%d, page=%u\n", ret, index); 1025 1026 return ret; 1027 } 1028 1029 static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec, 1030 u32 index, int offset, struct bio *bio) 1031 { 1032 int ret; 1033 struct page *page; 1034 1035 page = bvec->bv_page; 1036 if (is_partial_io(bvec)) { 1037 /* Use a temporary buffer to decompress the page */ 1038 page = alloc_page(GFP_NOIO|__GFP_HIGHMEM); 1039 if (!page) 1040 return -ENOMEM; 1041 } 1042 1043 ret = __zram_bvec_read(zram, page, index, bio, is_partial_io(bvec)); 1044 if (unlikely(ret)) 1045 goto out; 1046 1047 if (is_partial_io(bvec)) { 1048 void *dst = kmap_atomic(bvec->bv_page); 1049 void *src = kmap_atomic(page); 1050 1051 memcpy(dst + bvec->bv_offset, src + offset, bvec->bv_len); 1052 kunmap_atomic(src); 1053 kunmap_atomic(dst); 1054 } 1055 out: 1056 if (is_partial_io(bvec)) 1057 __free_page(page); 1058 1059 return ret; 1060 } 1061 1062 static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec, 1063 u32 index, struct bio *bio) 1064 { 1065 int ret = 0; 1066 unsigned long alloced_pages; 1067 unsigned long handle = 0; 1068 unsigned int comp_len = 0; 1069 void *src, *dst, *mem; 1070 struct zcomp_strm *zstrm; 1071 struct page *page = bvec->bv_page; 1072 unsigned long element = 0; 1073 enum zram_pageflags flags = 0; 1074 bool allow_wb = true; 1075 1076 mem = kmap_atomic(page); 1077 if (page_same_filled(mem, &element)) { 1078 kunmap_atomic(mem); 1079 /* Free memory associated with this sector now. */ 1080 flags = ZRAM_SAME; 1081 atomic64_inc(&zram->stats.same_pages); 1082 goto out; 1083 } 1084 kunmap_atomic(mem); 1085 1086 compress_again: 1087 zstrm = zcomp_stream_get(zram->comp); 1088 src = kmap_atomic(page); 1089 ret = zcomp_compress(zstrm, src, &comp_len); 1090 kunmap_atomic(src); 1091 1092 if (unlikely(ret)) { 1093 zcomp_stream_put(zram->comp); 1094 pr_err("Compression failed! err=%d\n", ret); 1095 zs_free(zram->mem_pool, handle); 1096 return ret; 1097 } 1098 1099 if (unlikely(comp_len >= huge_class_size)) { 1100 comp_len = PAGE_SIZE; 1101 if (zram_wb_enabled(zram) && allow_wb) { 1102 zcomp_stream_put(zram->comp); 1103 ret = write_to_bdev(zram, bvec, index, bio, &element); 1104 if (!ret) { 1105 flags = ZRAM_WB; 1106 ret = 1; 1107 goto out; 1108 } 1109 allow_wb = false; 1110 goto compress_again; 1111 } 1112 } 1113 1114 /* 1115 * handle allocation has 2 paths: 1116 * a) fast path is executed with preemption disabled (for 1117 * per-cpu streams) and has __GFP_DIRECT_RECLAIM bit clear, 1118 * since we can't sleep; 1119 * b) slow path enables preemption and attempts to allocate 1120 * the page with __GFP_DIRECT_RECLAIM bit set. we have to 1121 * put per-cpu compression stream and, thus, to re-do 1122 * the compression once handle is allocated. 1123 * 1124 * if we have a 'non-null' handle here then we are coming 1125 * from the slow path and handle has already been allocated. 1126 */ 1127 if (!handle) 1128 handle = zs_malloc(zram->mem_pool, comp_len, 1129 __GFP_KSWAPD_RECLAIM | 1130 __GFP_NOWARN | 1131 __GFP_HIGHMEM | 1132 __GFP_MOVABLE); 1133 if (!handle) { 1134 zcomp_stream_put(zram->comp); 1135 atomic64_inc(&zram->stats.writestall); 1136 handle = zs_malloc(zram->mem_pool, comp_len, 1137 GFP_NOIO | __GFP_HIGHMEM | 1138 __GFP_MOVABLE); 1139 if (handle) 1140 goto compress_again; 1141 return -ENOMEM; 1142 } 1143 1144 alloced_pages = zs_get_total_pages(zram->mem_pool); 1145 update_used_max(zram, alloced_pages); 1146 1147 if (zram->limit_pages && alloced_pages > zram->limit_pages) { 1148 zcomp_stream_put(zram->comp); 1149 zs_free(zram->mem_pool, handle); 1150 return -ENOMEM; 1151 } 1152 1153 dst = zs_map_object(zram->mem_pool, handle, ZS_MM_WO); 1154 1155 src = zstrm->buffer; 1156 if (comp_len == PAGE_SIZE) 1157 src = kmap_atomic(page); 1158 memcpy(dst, src, comp_len); 1159 if (comp_len == PAGE_SIZE) 1160 kunmap_atomic(src); 1161 1162 zcomp_stream_put(zram->comp); 1163 zs_unmap_object(zram->mem_pool, handle); 1164 atomic64_add(comp_len, &zram->stats.compr_data_size); 1165 out: 1166 /* 1167 * Free memory associated with this sector 1168 * before overwriting unused sectors. 1169 */ 1170 zram_slot_lock(zram, index); 1171 zram_free_page(zram, index); 1172 1173 if (comp_len == PAGE_SIZE) { 1174 zram_set_flag(zram, index, ZRAM_HUGE); 1175 atomic64_inc(&zram->stats.huge_pages); 1176 } 1177 1178 if (flags) { 1179 zram_set_flag(zram, index, flags); 1180 zram_set_element(zram, index, element); 1181 } else { 1182 zram_set_handle(zram, index, handle); 1183 zram_set_obj_size(zram, index, comp_len); 1184 } 1185 zram_slot_unlock(zram, index); 1186 1187 /* Update stats */ 1188 atomic64_inc(&zram->stats.pages_stored); 1189 return ret; 1190 } 1191 1192 static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, 1193 u32 index, int offset, struct bio *bio) 1194 { 1195 int ret; 1196 struct page *page = NULL; 1197 void *src; 1198 struct bio_vec vec; 1199 1200 vec = *bvec; 1201 if (is_partial_io(bvec)) { 1202 void *dst; 1203 /* 1204 * This is a partial IO. We need to read the full page 1205 * before to write the changes. 1206 */ 1207 page = alloc_page(GFP_NOIO|__GFP_HIGHMEM); 1208 if (!page) 1209 return -ENOMEM; 1210 1211 ret = __zram_bvec_read(zram, page, index, bio, true); 1212 if (ret) 1213 goto out; 1214 1215 src = kmap_atomic(bvec->bv_page); 1216 dst = kmap_atomic(page); 1217 memcpy(dst + offset, src + bvec->bv_offset, bvec->bv_len); 1218 kunmap_atomic(dst); 1219 kunmap_atomic(src); 1220 1221 vec.bv_page = page; 1222 vec.bv_len = PAGE_SIZE; 1223 vec.bv_offset = 0; 1224 } 1225 1226 ret = __zram_bvec_write(zram, &vec, index, bio); 1227 out: 1228 if (is_partial_io(bvec)) 1229 __free_page(page); 1230 return ret; 1231 } 1232 1233 /* 1234 * zram_bio_discard - handler on discard request 1235 * @index: physical block index in PAGE_SIZE units 1236 * @offset: byte offset within physical block 1237 */ 1238 static void zram_bio_discard(struct zram *zram, u32 index, 1239 int offset, struct bio *bio) 1240 { 1241 size_t n = bio->bi_iter.bi_size; 1242 1243 /* 1244 * zram manages data in physical block size units. Because logical block 1245 * size isn't identical with physical block size on some arch, we 1246 * could get a discard request pointing to a specific offset within a 1247 * certain physical block. Although we can handle this request by 1248 * reading that physiclal block and decompressing and partially zeroing 1249 * and re-compressing and then re-storing it, this isn't reasonable 1250 * because our intent with a discard request is to save memory. So 1251 * skipping this logical block is appropriate here. 1252 */ 1253 if (offset) { 1254 if (n <= (PAGE_SIZE - offset)) 1255 return; 1256 1257 n -= (PAGE_SIZE - offset); 1258 index++; 1259 } 1260 1261 while (n >= PAGE_SIZE) { 1262 zram_slot_lock(zram, index); 1263 zram_free_page(zram, index); 1264 zram_slot_unlock(zram, index); 1265 atomic64_inc(&zram->stats.notify_free); 1266 index++; 1267 n -= PAGE_SIZE; 1268 } 1269 } 1270 1271 /* 1272 * Returns errno if it has some problem. Otherwise return 0 or 1. 1273 * Returns 0 if IO request was done synchronously 1274 * Returns 1 if IO request was successfully submitted. 1275 */ 1276 static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index, 1277 int offset, bool is_write, struct bio *bio) 1278 { 1279 unsigned long start_time = jiffies; 1280 int rw_acct = is_write ? REQ_OP_WRITE : REQ_OP_READ; 1281 struct request_queue *q = zram->disk->queue; 1282 int ret; 1283 1284 generic_start_io_acct(q, rw_acct, bvec->bv_len >> SECTOR_SHIFT, 1285 &zram->disk->part0); 1286 1287 if (!is_write) { 1288 atomic64_inc(&zram->stats.num_reads); 1289 ret = zram_bvec_read(zram, bvec, index, offset, bio); 1290 flush_dcache_page(bvec->bv_page); 1291 } else { 1292 atomic64_inc(&zram->stats.num_writes); 1293 ret = zram_bvec_write(zram, bvec, index, offset, bio); 1294 } 1295 1296 generic_end_io_acct(q, rw_acct, &zram->disk->part0, start_time); 1297 1298 zram_slot_lock(zram, index); 1299 zram_accessed(zram, index); 1300 zram_slot_unlock(zram, index); 1301 1302 if (unlikely(ret < 0)) { 1303 if (!is_write) 1304 atomic64_inc(&zram->stats.failed_reads); 1305 else 1306 atomic64_inc(&zram->stats.failed_writes); 1307 } 1308 1309 return ret; 1310 } 1311 1312 static void __zram_make_request(struct zram *zram, struct bio *bio) 1313 { 1314 int offset; 1315 u32 index; 1316 struct bio_vec bvec; 1317 struct bvec_iter iter; 1318 1319 index = bio->bi_iter.bi_sector >> SECTORS_PER_PAGE_SHIFT; 1320 offset = (bio->bi_iter.bi_sector & 1321 (SECTORS_PER_PAGE - 1)) << SECTOR_SHIFT; 1322 1323 switch (bio_op(bio)) { 1324 case REQ_OP_DISCARD: 1325 case REQ_OP_WRITE_ZEROES: 1326 zram_bio_discard(zram, index, offset, bio); 1327 bio_endio(bio); 1328 return; 1329 default: 1330 break; 1331 } 1332 1333 bio_for_each_segment(bvec, bio, iter) { 1334 struct bio_vec bv = bvec; 1335 unsigned int unwritten = bvec.bv_len; 1336 1337 do { 1338 bv.bv_len = min_t(unsigned int, PAGE_SIZE - offset, 1339 unwritten); 1340 if (zram_bvec_rw(zram, &bv, index, offset, 1341 op_is_write(bio_op(bio)), bio) < 0) 1342 goto out; 1343 1344 bv.bv_offset += bv.bv_len; 1345 unwritten -= bv.bv_len; 1346 1347 update_position(&index, &offset, &bv); 1348 } while (unwritten); 1349 } 1350 1351 bio_endio(bio); 1352 return; 1353 1354 out: 1355 bio_io_error(bio); 1356 } 1357 1358 /* 1359 * Handler function for all zram I/O requests. 1360 */ 1361 static blk_qc_t zram_make_request(struct request_queue *queue, struct bio *bio) 1362 { 1363 struct zram *zram = queue->queuedata; 1364 1365 if (!valid_io_request(zram, bio->bi_iter.bi_sector, 1366 bio->bi_iter.bi_size)) { 1367 atomic64_inc(&zram->stats.invalid_io); 1368 goto error; 1369 } 1370 1371 __zram_make_request(zram, bio); 1372 return BLK_QC_T_NONE; 1373 1374 error: 1375 bio_io_error(bio); 1376 return BLK_QC_T_NONE; 1377 } 1378 1379 static void zram_slot_free_notify(struct block_device *bdev, 1380 unsigned long index) 1381 { 1382 struct zram *zram; 1383 1384 zram = bdev->bd_disk->private_data; 1385 1386 zram_slot_lock(zram, index); 1387 zram_free_page(zram, index); 1388 zram_slot_unlock(zram, index); 1389 atomic64_inc(&zram->stats.notify_free); 1390 } 1391 1392 static int zram_rw_page(struct block_device *bdev, sector_t sector, 1393 struct page *page, bool is_write) 1394 { 1395 int offset, ret; 1396 u32 index; 1397 struct zram *zram; 1398 struct bio_vec bv; 1399 1400 if (PageTransHuge(page)) 1401 return -ENOTSUPP; 1402 zram = bdev->bd_disk->private_data; 1403 1404 if (!valid_io_request(zram, sector, PAGE_SIZE)) { 1405 atomic64_inc(&zram->stats.invalid_io); 1406 ret = -EINVAL; 1407 goto out; 1408 } 1409 1410 index = sector >> SECTORS_PER_PAGE_SHIFT; 1411 offset = (sector & (SECTORS_PER_PAGE - 1)) << SECTOR_SHIFT; 1412 1413 bv.bv_page = page; 1414 bv.bv_len = PAGE_SIZE; 1415 bv.bv_offset = 0; 1416 1417 ret = zram_bvec_rw(zram, &bv, index, offset, is_write, NULL); 1418 out: 1419 /* 1420 * If I/O fails, just return error(ie, non-zero) without 1421 * calling page_endio. 1422 * It causes resubmit the I/O with bio request by upper functions 1423 * of rw_page(e.g., swap_readpage, __swap_writepage) and 1424 * bio->bi_end_io does things to handle the error 1425 * (e.g., SetPageError, set_page_dirty and extra works). 1426 */ 1427 if (unlikely(ret < 0)) 1428 return ret; 1429 1430 switch (ret) { 1431 case 0: 1432 page_endio(page, is_write, 0); 1433 break; 1434 case 1: 1435 ret = 0; 1436 break; 1437 default: 1438 WARN_ON(1); 1439 } 1440 return ret; 1441 } 1442 1443 static void zram_reset_device(struct zram *zram) 1444 { 1445 struct zcomp *comp; 1446 u64 disksize; 1447 1448 down_write(&zram->init_lock); 1449 1450 zram->limit_pages = 0; 1451 1452 if (!init_done(zram)) { 1453 up_write(&zram->init_lock); 1454 return; 1455 } 1456 1457 comp = zram->comp; 1458 disksize = zram->disksize; 1459 zram->disksize = 0; 1460 1461 set_capacity(zram->disk, 0); 1462 part_stat_set_all(&zram->disk->part0, 0); 1463 1464 up_write(&zram->init_lock); 1465 /* I/O operation under all of CPU are done so let's free */ 1466 zram_meta_free(zram, disksize); 1467 memset(&zram->stats, 0, sizeof(zram->stats)); 1468 zcomp_destroy(comp); 1469 reset_bdev(zram); 1470 } 1471 1472 static ssize_t disksize_store(struct device *dev, 1473 struct device_attribute *attr, const char *buf, size_t len) 1474 { 1475 u64 disksize; 1476 struct zcomp *comp; 1477 struct zram *zram = dev_to_zram(dev); 1478 int err; 1479 1480 disksize = memparse(buf, NULL); 1481 if (!disksize) 1482 return -EINVAL; 1483 1484 down_write(&zram->init_lock); 1485 if (init_done(zram)) { 1486 pr_info("Cannot change disksize for initialized device\n"); 1487 err = -EBUSY; 1488 goto out_unlock; 1489 } 1490 1491 disksize = PAGE_ALIGN(disksize); 1492 if (!zram_meta_alloc(zram, disksize)) { 1493 err = -ENOMEM; 1494 goto out_unlock; 1495 } 1496 1497 comp = zcomp_create(zram->compressor); 1498 if (IS_ERR(comp)) { 1499 pr_err("Cannot initialise %s compressing backend\n", 1500 zram->compressor); 1501 err = PTR_ERR(comp); 1502 goto out_free_meta; 1503 } 1504 1505 zram->comp = comp; 1506 zram->disksize = disksize; 1507 set_capacity(zram->disk, zram->disksize >> SECTOR_SHIFT); 1508 1509 revalidate_disk(zram->disk); 1510 up_write(&zram->init_lock); 1511 1512 return len; 1513 1514 out_free_meta: 1515 zram_meta_free(zram, disksize); 1516 out_unlock: 1517 up_write(&zram->init_lock); 1518 return err; 1519 } 1520 1521 static ssize_t reset_store(struct device *dev, 1522 struct device_attribute *attr, const char *buf, size_t len) 1523 { 1524 int ret; 1525 unsigned short do_reset; 1526 struct zram *zram; 1527 struct block_device *bdev; 1528 1529 ret = kstrtou16(buf, 10, &do_reset); 1530 if (ret) 1531 return ret; 1532 1533 if (!do_reset) 1534 return -EINVAL; 1535 1536 zram = dev_to_zram(dev); 1537 bdev = bdget_disk(zram->disk, 0); 1538 if (!bdev) 1539 return -ENOMEM; 1540 1541 mutex_lock(&bdev->bd_mutex); 1542 /* Do not reset an active device or claimed device */ 1543 if (bdev->bd_openers || zram->claim) { 1544 mutex_unlock(&bdev->bd_mutex); 1545 bdput(bdev); 1546 return -EBUSY; 1547 } 1548 1549 /* From now on, anyone can't open /dev/zram[0-9] */ 1550 zram->claim = true; 1551 mutex_unlock(&bdev->bd_mutex); 1552 1553 /* Make sure all the pending I/O are finished */ 1554 fsync_bdev(bdev); 1555 zram_reset_device(zram); 1556 revalidate_disk(zram->disk); 1557 bdput(bdev); 1558 1559 mutex_lock(&bdev->bd_mutex); 1560 zram->claim = false; 1561 mutex_unlock(&bdev->bd_mutex); 1562 1563 return len; 1564 } 1565 1566 static int zram_open(struct block_device *bdev, fmode_t mode) 1567 { 1568 int ret = 0; 1569 struct zram *zram; 1570 1571 WARN_ON(!mutex_is_locked(&bdev->bd_mutex)); 1572 1573 zram = bdev->bd_disk->private_data; 1574 /* zram was claimed to reset so open request fails */ 1575 if (zram->claim) 1576 ret = -EBUSY; 1577 1578 return ret; 1579 } 1580 1581 static const struct block_device_operations zram_devops = { 1582 .open = zram_open, 1583 .swap_slot_free_notify = zram_slot_free_notify, 1584 .rw_page = zram_rw_page, 1585 .owner = THIS_MODULE 1586 }; 1587 1588 static DEVICE_ATTR_WO(compact); 1589 static DEVICE_ATTR_RW(disksize); 1590 static DEVICE_ATTR_RO(initstate); 1591 static DEVICE_ATTR_WO(reset); 1592 static DEVICE_ATTR_WO(mem_limit); 1593 static DEVICE_ATTR_WO(mem_used_max); 1594 static DEVICE_ATTR_RW(max_comp_streams); 1595 static DEVICE_ATTR_RW(comp_algorithm); 1596 #ifdef CONFIG_ZRAM_WRITEBACK 1597 static DEVICE_ATTR_RW(backing_dev); 1598 #endif 1599 1600 static struct attribute *zram_disk_attrs[] = { 1601 &dev_attr_disksize.attr, 1602 &dev_attr_initstate.attr, 1603 &dev_attr_reset.attr, 1604 &dev_attr_compact.attr, 1605 &dev_attr_mem_limit.attr, 1606 &dev_attr_mem_used_max.attr, 1607 &dev_attr_max_comp_streams.attr, 1608 &dev_attr_comp_algorithm.attr, 1609 #ifdef CONFIG_ZRAM_WRITEBACK 1610 &dev_attr_backing_dev.attr, 1611 #endif 1612 &dev_attr_io_stat.attr, 1613 &dev_attr_mm_stat.attr, 1614 &dev_attr_debug_stat.attr, 1615 NULL, 1616 }; 1617 1618 static const struct attribute_group zram_disk_attr_group = { 1619 .attrs = zram_disk_attrs, 1620 }; 1621 1622 /* 1623 * Allocate and initialize new zram device. the function returns 1624 * '>= 0' device_id upon success, and negative value otherwise. 1625 */ 1626 static int zram_add(void) 1627 { 1628 struct zram *zram; 1629 struct request_queue *queue; 1630 int ret, device_id; 1631 1632 zram = kzalloc(sizeof(struct zram), GFP_KERNEL); 1633 if (!zram) 1634 return -ENOMEM; 1635 1636 ret = idr_alloc(&zram_index_idr, zram, 0, 0, GFP_KERNEL); 1637 if (ret < 0) 1638 goto out_free_dev; 1639 device_id = ret; 1640 1641 init_rwsem(&zram->init_lock); 1642 1643 queue = blk_alloc_queue(GFP_KERNEL); 1644 if (!queue) { 1645 pr_err("Error allocating disk queue for device %d\n", 1646 device_id); 1647 ret = -ENOMEM; 1648 goto out_free_idr; 1649 } 1650 1651 blk_queue_make_request(queue, zram_make_request); 1652 1653 /* gendisk structure */ 1654 zram->disk = alloc_disk(1); 1655 if (!zram->disk) { 1656 pr_err("Error allocating disk structure for device %d\n", 1657 device_id); 1658 ret = -ENOMEM; 1659 goto out_free_queue; 1660 } 1661 1662 zram->disk->major = zram_major; 1663 zram->disk->first_minor = device_id; 1664 zram->disk->fops = &zram_devops; 1665 zram->disk->queue = queue; 1666 zram->disk->queue->queuedata = zram; 1667 zram->disk->private_data = zram; 1668 snprintf(zram->disk->disk_name, 16, "zram%d", device_id); 1669 1670 /* Actual capacity set using syfs (/sys/block/zram<id>/disksize */ 1671 set_capacity(zram->disk, 0); 1672 /* zram devices sort of resembles non-rotational disks */ 1673 blk_queue_flag_set(QUEUE_FLAG_NONROT, zram->disk->queue); 1674 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, zram->disk->queue); 1675 1676 /* 1677 * To ensure that we always get PAGE_SIZE aligned 1678 * and n*PAGE_SIZED sized I/O requests. 1679 */ 1680 blk_queue_physical_block_size(zram->disk->queue, PAGE_SIZE); 1681 blk_queue_logical_block_size(zram->disk->queue, 1682 ZRAM_LOGICAL_BLOCK_SIZE); 1683 blk_queue_io_min(zram->disk->queue, PAGE_SIZE); 1684 blk_queue_io_opt(zram->disk->queue, PAGE_SIZE); 1685 zram->disk->queue->limits.discard_granularity = PAGE_SIZE; 1686 blk_queue_max_discard_sectors(zram->disk->queue, UINT_MAX); 1687 blk_queue_flag_set(QUEUE_FLAG_DISCARD, zram->disk->queue); 1688 1689 /* 1690 * zram_bio_discard() will clear all logical blocks if logical block 1691 * size is identical with physical block size(PAGE_SIZE). But if it is 1692 * different, we will skip discarding some parts of logical blocks in 1693 * the part of the request range which isn't aligned to physical block 1694 * size. So we can't ensure that all discarded logical blocks are 1695 * zeroed. 1696 */ 1697 if (ZRAM_LOGICAL_BLOCK_SIZE == PAGE_SIZE) 1698 blk_queue_max_write_zeroes_sectors(zram->disk->queue, UINT_MAX); 1699 1700 zram->disk->queue->backing_dev_info->capabilities |= 1701 (BDI_CAP_STABLE_WRITES | BDI_CAP_SYNCHRONOUS_IO); 1702 add_disk(zram->disk); 1703 1704 ret = sysfs_create_group(&disk_to_dev(zram->disk)->kobj, 1705 &zram_disk_attr_group); 1706 if (ret < 0) { 1707 pr_err("Error creating sysfs group for device %d\n", 1708 device_id); 1709 goto out_free_disk; 1710 } 1711 strlcpy(zram->compressor, default_compressor, sizeof(zram->compressor)); 1712 1713 zram_debugfs_register(zram); 1714 pr_info("Added device: %s\n", zram->disk->disk_name); 1715 return device_id; 1716 1717 out_free_disk: 1718 del_gendisk(zram->disk); 1719 put_disk(zram->disk); 1720 out_free_queue: 1721 blk_cleanup_queue(queue); 1722 out_free_idr: 1723 idr_remove(&zram_index_idr, device_id); 1724 out_free_dev: 1725 kfree(zram); 1726 return ret; 1727 } 1728 1729 static int zram_remove(struct zram *zram) 1730 { 1731 struct block_device *bdev; 1732 1733 bdev = bdget_disk(zram->disk, 0); 1734 if (!bdev) 1735 return -ENOMEM; 1736 1737 mutex_lock(&bdev->bd_mutex); 1738 if (bdev->bd_openers || zram->claim) { 1739 mutex_unlock(&bdev->bd_mutex); 1740 bdput(bdev); 1741 return -EBUSY; 1742 } 1743 1744 zram->claim = true; 1745 mutex_unlock(&bdev->bd_mutex); 1746 1747 zram_debugfs_unregister(zram); 1748 /* 1749 * Remove sysfs first, so no one will perform a disksize 1750 * store while we destroy the devices. This also helps during 1751 * hot_remove -- zram_reset_device() is the last holder of 1752 * ->init_lock, no later/concurrent disksize_store() or any 1753 * other sysfs handlers are possible. 1754 */ 1755 sysfs_remove_group(&disk_to_dev(zram->disk)->kobj, 1756 &zram_disk_attr_group); 1757 1758 /* Make sure all the pending I/O are finished */ 1759 fsync_bdev(bdev); 1760 zram_reset_device(zram); 1761 bdput(bdev); 1762 1763 pr_info("Removed device: %s\n", zram->disk->disk_name); 1764 1765 del_gendisk(zram->disk); 1766 blk_cleanup_queue(zram->disk->queue); 1767 put_disk(zram->disk); 1768 kfree(zram); 1769 return 0; 1770 } 1771 1772 /* zram-control sysfs attributes */ 1773 1774 /* 1775 * NOTE: hot_add attribute is not the usual read-only sysfs attribute. In a 1776 * sense that reading from this file does alter the state of your system -- it 1777 * creates a new un-initialized zram device and returns back this device's 1778 * device_id (or an error code if it fails to create a new device). 1779 */ 1780 static ssize_t hot_add_show(struct class *class, 1781 struct class_attribute *attr, 1782 char *buf) 1783 { 1784 int ret; 1785 1786 mutex_lock(&zram_index_mutex); 1787 ret = zram_add(); 1788 mutex_unlock(&zram_index_mutex); 1789 1790 if (ret < 0) 1791 return ret; 1792 return scnprintf(buf, PAGE_SIZE, "%d\n", ret); 1793 } 1794 static CLASS_ATTR_RO(hot_add); 1795 1796 static ssize_t hot_remove_store(struct class *class, 1797 struct class_attribute *attr, 1798 const char *buf, 1799 size_t count) 1800 { 1801 struct zram *zram; 1802 int ret, dev_id; 1803 1804 /* dev_id is gendisk->first_minor, which is `int' */ 1805 ret = kstrtoint(buf, 10, &dev_id); 1806 if (ret) 1807 return ret; 1808 if (dev_id < 0) 1809 return -EINVAL; 1810 1811 mutex_lock(&zram_index_mutex); 1812 1813 zram = idr_find(&zram_index_idr, dev_id); 1814 if (zram) { 1815 ret = zram_remove(zram); 1816 if (!ret) 1817 idr_remove(&zram_index_idr, dev_id); 1818 } else { 1819 ret = -ENODEV; 1820 } 1821 1822 mutex_unlock(&zram_index_mutex); 1823 return ret ? ret : count; 1824 } 1825 static CLASS_ATTR_WO(hot_remove); 1826 1827 static struct attribute *zram_control_class_attrs[] = { 1828 &class_attr_hot_add.attr, 1829 &class_attr_hot_remove.attr, 1830 NULL, 1831 }; 1832 ATTRIBUTE_GROUPS(zram_control_class); 1833 1834 static struct class zram_control_class = { 1835 .name = "zram-control", 1836 .owner = THIS_MODULE, 1837 .class_groups = zram_control_class_groups, 1838 }; 1839 1840 static int zram_remove_cb(int id, void *ptr, void *data) 1841 { 1842 zram_remove(ptr); 1843 return 0; 1844 } 1845 1846 static void destroy_devices(void) 1847 { 1848 class_unregister(&zram_control_class); 1849 idr_for_each(&zram_index_idr, &zram_remove_cb, NULL); 1850 zram_debugfs_destroy(); 1851 idr_destroy(&zram_index_idr); 1852 unregister_blkdev(zram_major, "zram"); 1853 cpuhp_remove_multi_state(CPUHP_ZCOMP_PREPARE); 1854 } 1855 1856 static int __init zram_init(void) 1857 { 1858 int ret; 1859 1860 ret = cpuhp_setup_state_multi(CPUHP_ZCOMP_PREPARE, "block/zram:prepare", 1861 zcomp_cpu_up_prepare, zcomp_cpu_dead); 1862 if (ret < 0) 1863 return ret; 1864 1865 ret = class_register(&zram_control_class); 1866 if (ret) { 1867 pr_err("Unable to register zram-control class\n"); 1868 cpuhp_remove_multi_state(CPUHP_ZCOMP_PREPARE); 1869 return ret; 1870 } 1871 1872 zram_debugfs_create(); 1873 zram_major = register_blkdev(0, "zram"); 1874 if (zram_major <= 0) { 1875 pr_err("Unable to get major number\n"); 1876 class_unregister(&zram_control_class); 1877 cpuhp_remove_multi_state(CPUHP_ZCOMP_PREPARE); 1878 return -EBUSY; 1879 } 1880 1881 while (num_devices != 0) { 1882 mutex_lock(&zram_index_mutex); 1883 ret = zram_add(); 1884 mutex_unlock(&zram_index_mutex); 1885 if (ret < 0) 1886 goto out_error; 1887 num_devices--; 1888 } 1889 1890 return 0; 1891 1892 out_error: 1893 destroy_devices(); 1894 return ret; 1895 } 1896 1897 static void __exit zram_exit(void) 1898 { 1899 destroy_devices(); 1900 } 1901 1902 module_init(zram_init); 1903 module_exit(zram_exit); 1904 1905 module_param(num_devices, uint, 0); 1906 MODULE_PARM_DESC(num_devices, "Number of pre-created zram devices"); 1907 1908 MODULE_LICENSE("Dual BSD/GPL"); 1909 MODULE_AUTHOR("Nitin Gupta <ngupta@vflare.org>"); 1910 MODULE_DESCRIPTION("Compressed RAM Block Device"); 1911