perf bench futex: Cache align the worker struct
[linux/fpc-iii.git] / drivers / block / zram / zram_drv.c
blob04365b17ee67fe668f4bfc1f5683846af999009a
1 /*
2 * Compressed RAM block device
4 * Copyright (C) 2008, 2009, 2010 Nitin Gupta
5 * 2012, 2013 Minchan Kim
7 * This code is released using a dual license strategy: BSD/GPL
8 * You can choose the licence that better fits your requirements.
10 * Released under the terms of 3-clause BSD License
11 * Released under the terms of GNU General Public License Version 2.0
15 #define KMSG_COMPONENT "zram"
16 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
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/string.h>
29 #include <linux/vmalloc.h>
30 #include <linux/err.h>
31 #include <linux/idr.h>
32 #include <linux/sysfs.h>
34 #include "zram_drv.h"
36 static DEFINE_IDR(zram_index_idr);
37 /* idr index must be protected */
38 static DEFINE_MUTEX(zram_index_mutex);
40 static int zram_major;
41 static const char *default_compressor = "lzo";
43 /* Module params (documentation at end) */
44 static unsigned int num_devices = 1;
46 static inline void deprecated_attr_warn(const char *name)
48 pr_warn_once("%d (%s) Attribute %s (and others) will be removed. %s\n",
49 task_pid_nr(current),
50 current->comm,
51 name,
52 "See zram documentation.");
55 #define ZRAM_ATTR_RO(name) \
56 static ssize_t name##_show(struct device *d, \
57 struct device_attribute *attr, char *b) \
58 { \
59 struct zram *zram = dev_to_zram(d); \
61 deprecated_attr_warn(__stringify(name)); \
62 return scnprintf(b, PAGE_SIZE, "%llu\n", \
63 (u64)atomic64_read(&zram->stats.name)); \
64 } \
65 static DEVICE_ATTR_RO(name);
67 static inline bool init_done(struct zram *zram)
69 return zram->disksize;
72 static inline struct zram *dev_to_zram(struct device *dev)
74 return (struct zram *)dev_to_disk(dev)->private_data;
77 /* flag operations require table entry bit_spin_lock() being held */
78 static int zram_test_flag(struct zram_meta *meta, u32 index,
79 enum zram_pageflags flag)
81 return meta->table[index].value & BIT(flag);
84 static void zram_set_flag(struct zram_meta *meta, u32 index,
85 enum zram_pageflags flag)
87 meta->table[index].value |= BIT(flag);
90 static void zram_clear_flag(struct zram_meta *meta, u32 index,
91 enum zram_pageflags flag)
93 meta->table[index].value &= ~BIT(flag);
96 static size_t zram_get_obj_size(struct zram_meta *meta, u32 index)
98 return meta->table[index].value & (BIT(ZRAM_FLAG_SHIFT) - 1);
101 static void zram_set_obj_size(struct zram_meta *meta,
102 u32 index, size_t size)
104 unsigned long flags = meta->table[index].value >> ZRAM_FLAG_SHIFT;
106 meta->table[index].value = (flags << ZRAM_FLAG_SHIFT) | size;
109 static inline bool is_partial_io(struct bio_vec *bvec)
111 return bvec->bv_len != PAGE_SIZE;
115 * Check if request is within bounds and aligned on zram logical blocks.
117 static inline bool valid_io_request(struct zram *zram,
118 sector_t start, unsigned int size)
120 u64 end, bound;
122 /* unaligned request */
123 if (unlikely(start & (ZRAM_SECTOR_PER_LOGICAL_BLOCK - 1)))
124 return false;
125 if (unlikely(size & (ZRAM_LOGICAL_BLOCK_SIZE - 1)))
126 return false;
128 end = start + (size >> SECTOR_SHIFT);
129 bound = zram->disksize >> SECTOR_SHIFT;
130 /* out of range range */
131 if (unlikely(start >= bound || end > bound || start > end))
132 return false;
134 /* I/O request is valid */
135 return true;
138 static void update_position(u32 *index, int *offset, struct bio_vec *bvec)
140 if (*offset + bvec->bv_len >= PAGE_SIZE)
141 (*index)++;
142 *offset = (*offset + bvec->bv_len) % PAGE_SIZE;
145 static inline void update_used_max(struct zram *zram,
146 const unsigned long pages)
148 unsigned long old_max, cur_max;
150 old_max = atomic_long_read(&zram->stats.max_used_pages);
152 do {
153 cur_max = old_max;
154 if (pages > cur_max)
155 old_max = atomic_long_cmpxchg(
156 &zram->stats.max_used_pages, cur_max, pages);
157 } while (old_max != cur_max);
160 static bool page_zero_filled(void *ptr)
162 unsigned int pos;
163 unsigned long *page;
165 page = (unsigned long *)ptr;
167 for (pos = 0; pos != PAGE_SIZE / sizeof(*page); pos++) {
168 if (page[pos])
169 return false;
172 return true;
175 static void handle_zero_page(struct bio_vec *bvec)
177 struct page *page = bvec->bv_page;
178 void *user_mem;
180 user_mem = kmap_atomic(page);
181 if (is_partial_io(bvec))
182 memset(user_mem + bvec->bv_offset, 0, bvec->bv_len);
183 else
184 clear_page(user_mem);
185 kunmap_atomic(user_mem);
187 flush_dcache_page(page);
190 static ssize_t initstate_show(struct device *dev,
191 struct device_attribute *attr, char *buf)
193 u32 val;
194 struct zram *zram = dev_to_zram(dev);
196 down_read(&zram->init_lock);
197 val = init_done(zram);
198 up_read(&zram->init_lock);
200 return scnprintf(buf, PAGE_SIZE, "%u\n", val);
203 static ssize_t disksize_show(struct device *dev,
204 struct device_attribute *attr, char *buf)
206 struct zram *zram = dev_to_zram(dev);
208 return scnprintf(buf, PAGE_SIZE, "%llu\n", zram->disksize);
211 static ssize_t orig_data_size_show(struct device *dev,
212 struct device_attribute *attr, char *buf)
214 struct zram *zram = dev_to_zram(dev);
216 deprecated_attr_warn("orig_data_size");
217 return scnprintf(buf, PAGE_SIZE, "%llu\n",
218 (u64)(atomic64_read(&zram->stats.pages_stored)) << PAGE_SHIFT);
221 static ssize_t mem_used_total_show(struct device *dev,
222 struct device_attribute *attr, char *buf)
224 u64 val = 0;
225 struct zram *zram = dev_to_zram(dev);
227 deprecated_attr_warn("mem_used_total");
228 down_read(&zram->init_lock);
229 if (init_done(zram)) {
230 struct zram_meta *meta = zram->meta;
231 val = zs_get_total_pages(meta->mem_pool);
233 up_read(&zram->init_lock);
235 return scnprintf(buf, PAGE_SIZE, "%llu\n", val << PAGE_SHIFT);
238 static ssize_t mem_limit_show(struct device *dev,
239 struct device_attribute *attr, char *buf)
241 u64 val;
242 struct zram *zram = dev_to_zram(dev);
244 deprecated_attr_warn("mem_limit");
245 down_read(&zram->init_lock);
246 val = zram->limit_pages;
247 up_read(&zram->init_lock);
249 return scnprintf(buf, PAGE_SIZE, "%llu\n", val << PAGE_SHIFT);
252 static ssize_t mem_limit_store(struct device *dev,
253 struct device_attribute *attr, const char *buf, size_t len)
255 u64 limit;
256 char *tmp;
257 struct zram *zram = dev_to_zram(dev);
259 limit = memparse(buf, &tmp);
260 if (buf == tmp) /* no chars parsed, invalid input */
261 return -EINVAL;
263 down_write(&zram->init_lock);
264 zram->limit_pages = PAGE_ALIGN(limit) >> PAGE_SHIFT;
265 up_write(&zram->init_lock);
267 return len;
270 static ssize_t mem_used_max_show(struct device *dev,
271 struct device_attribute *attr, char *buf)
273 u64 val = 0;
274 struct zram *zram = dev_to_zram(dev);
276 deprecated_attr_warn("mem_used_max");
277 down_read(&zram->init_lock);
278 if (init_done(zram))
279 val = atomic_long_read(&zram->stats.max_used_pages);
280 up_read(&zram->init_lock);
282 return scnprintf(buf, PAGE_SIZE, "%llu\n", val << PAGE_SHIFT);
285 static ssize_t mem_used_max_store(struct device *dev,
286 struct device_attribute *attr, const char *buf, size_t len)
288 int err;
289 unsigned long val;
290 struct zram *zram = dev_to_zram(dev);
292 err = kstrtoul(buf, 10, &val);
293 if (err || val != 0)
294 return -EINVAL;
296 down_read(&zram->init_lock);
297 if (init_done(zram)) {
298 struct zram_meta *meta = zram->meta;
299 atomic_long_set(&zram->stats.max_used_pages,
300 zs_get_total_pages(meta->mem_pool));
302 up_read(&zram->init_lock);
304 return len;
308 * We switched to per-cpu streams and this attr is not needed anymore.
309 * However, we will keep it around for some time, because:
310 * a) we may revert per-cpu streams in the future
311 * b) it's visible to user space and we need to follow our 2 years
312 * retirement rule; but we already have a number of 'soon to be
313 * altered' attrs, so max_comp_streams need to wait for the next
314 * layoff cycle.
316 static ssize_t max_comp_streams_show(struct device *dev,
317 struct device_attribute *attr, char *buf)
319 return scnprintf(buf, PAGE_SIZE, "%d\n", num_online_cpus());
322 static ssize_t max_comp_streams_store(struct device *dev,
323 struct device_attribute *attr, const char *buf, size_t len)
325 return len;
328 static ssize_t comp_algorithm_show(struct device *dev,
329 struct device_attribute *attr, char *buf)
331 size_t sz;
332 struct zram *zram = dev_to_zram(dev);
334 down_read(&zram->init_lock);
335 sz = zcomp_available_show(zram->compressor, buf);
336 up_read(&zram->init_lock);
338 return sz;
341 static ssize_t comp_algorithm_store(struct device *dev,
342 struct device_attribute *attr, const char *buf, size_t len)
344 struct zram *zram = dev_to_zram(dev);
345 char compressor[CRYPTO_MAX_ALG_NAME];
346 size_t sz;
348 strlcpy(compressor, buf, sizeof(compressor));
349 /* ignore trailing newline */
350 sz = strlen(compressor);
351 if (sz > 0 && compressor[sz - 1] == '\n')
352 compressor[sz - 1] = 0x00;
354 if (!zcomp_available_algorithm(compressor))
355 return -EINVAL;
357 down_write(&zram->init_lock);
358 if (init_done(zram)) {
359 up_write(&zram->init_lock);
360 pr_info("Can't change algorithm for initialized device\n");
361 return -EBUSY;
364 strlcpy(zram->compressor, compressor, sizeof(compressor));
365 up_write(&zram->init_lock);
366 return len;
369 static ssize_t compact_store(struct device *dev,
370 struct device_attribute *attr, const char *buf, size_t len)
372 struct zram *zram = dev_to_zram(dev);
373 struct zram_meta *meta;
375 down_read(&zram->init_lock);
376 if (!init_done(zram)) {
377 up_read(&zram->init_lock);
378 return -EINVAL;
381 meta = zram->meta;
382 zs_compact(meta->mem_pool);
383 up_read(&zram->init_lock);
385 return len;
388 static ssize_t io_stat_show(struct device *dev,
389 struct device_attribute *attr, char *buf)
391 struct zram *zram = dev_to_zram(dev);
392 ssize_t ret;
394 down_read(&zram->init_lock);
395 ret = scnprintf(buf, PAGE_SIZE,
396 "%8llu %8llu %8llu %8llu\n",
397 (u64)atomic64_read(&zram->stats.failed_reads),
398 (u64)atomic64_read(&zram->stats.failed_writes),
399 (u64)atomic64_read(&zram->stats.invalid_io),
400 (u64)atomic64_read(&zram->stats.notify_free));
401 up_read(&zram->init_lock);
403 return ret;
406 static ssize_t mm_stat_show(struct device *dev,
407 struct device_attribute *attr, char *buf)
409 struct zram *zram = dev_to_zram(dev);
410 struct zs_pool_stats pool_stats;
411 u64 orig_size, mem_used = 0;
412 long max_used;
413 ssize_t ret;
415 memset(&pool_stats, 0x00, sizeof(struct zs_pool_stats));
417 down_read(&zram->init_lock);
418 if (init_done(zram)) {
419 mem_used = zs_get_total_pages(zram->meta->mem_pool);
420 zs_pool_stats(zram->meta->mem_pool, &pool_stats);
423 orig_size = atomic64_read(&zram->stats.pages_stored);
424 max_used = atomic_long_read(&zram->stats.max_used_pages);
426 ret = scnprintf(buf, PAGE_SIZE,
427 "%8llu %8llu %8llu %8lu %8ld %8llu %8lu\n",
428 orig_size << PAGE_SHIFT,
429 (u64)atomic64_read(&zram->stats.compr_data_size),
430 mem_used << PAGE_SHIFT,
431 zram->limit_pages << PAGE_SHIFT,
432 max_used << PAGE_SHIFT,
433 (u64)atomic64_read(&zram->stats.zero_pages),
434 pool_stats.pages_compacted);
435 up_read(&zram->init_lock);
437 return ret;
440 static ssize_t debug_stat_show(struct device *dev,
441 struct device_attribute *attr, char *buf)
443 int version = 1;
444 struct zram *zram = dev_to_zram(dev);
445 ssize_t ret;
447 down_read(&zram->init_lock);
448 ret = scnprintf(buf, PAGE_SIZE,
449 "version: %d\n%8llu\n",
450 version,
451 (u64)atomic64_read(&zram->stats.writestall));
452 up_read(&zram->init_lock);
454 return ret;
457 static DEVICE_ATTR_RO(io_stat);
458 static DEVICE_ATTR_RO(mm_stat);
459 static DEVICE_ATTR_RO(debug_stat);
460 ZRAM_ATTR_RO(num_reads);
461 ZRAM_ATTR_RO(num_writes);
462 ZRAM_ATTR_RO(failed_reads);
463 ZRAM_ATTR_RO(failed_writes);
464 ZRAM_ATTR_RO(invalid_io);
465 ZRAM_ATTR_RO(notify_free);
466 ZRAM_ATTR_RO(zero_pages);
467 ZRAM_ATTR_RO(compr_data_size);
469 static inline bool zram_meta_get(struct zram *zram)
471 if (atomic_inc_not_zero(&zram->refcount))
472 return true;
473 return false;
476 static inline void zram_meta_put(struct zram *zram)
478 atomic_dec(&zram->refcount);
481 static void zram_meta_free(struct zram_meta *meta, u64 disksize)
483 size_t num_pages = disksize >> PAGE_SHIFT;
484 size_t index;
486 /* Free all pages that are still in this zram device */
487 for (index = 0; index < num_pages; index++) {
488 unsigned long handle = meta->table[index].handle;
490 if (!handle)
491 continue;
493 zs_free(meta->mem_pool, handle);
496 zs_destroy_pool(meta->mem_pool);
497 vfree(meta->table);
498 kfree(meta);
501 static struct zram_meta *zram_meta_alloc(char *pool_name, u64 disksize)
503 size_t num_pages;
504 struct zram_meta *meta = kmalloc(sizeof(*meta), GFP_KERNEL);
506 if (!meta)
507 return NULL;
509 num_pages = disksize >> PAGE_SHIFT;
510 meta->table = vzalloc(num_pages * sizeof(*meta->table));
511 if (!meta->table) {
512 pr_err("Error allocating zram address table\n");
513 goto out_error;
516 meta->mem_pool = zs_create_pool(pool_name);
517 if (!meta->mem_pool) {
518 pr_err("Error creating memory pool\n");
519 goto out_error;
522 return meta;
524 out_error:
525 vfree(meta->table);
526 kfree(meta);
527 return NULL;
531 * To protect concurrent access to the same index entry,
532 * caller should hold this table index entry's bit_spinlock to
533 * indicate this index entry is accessing.
535 static void zram_free_page(struct zram *zram, size_t index)
537 struct zram_meta *meta = zram->meta;
538 unsigned long handle = meta->table[index].handle;
540 if (unlikely(!handle)) {
542 * No memory is allocated for zero filled pages.
543 * Simply clear zero page flag.
545 if (zram_test_flag(meta, index, ZRAM_ZERO)) {
546 zram_clear_flag(meta, index, ZRAM_ZERO);
547 atomic64_dec(&zram->stats.zero_pages);
549 return;
552 zs_free(meta->mem_pool, handle);
554 atomic64_sub(zram_get_obj_size(meta, index),
555 &zram->stats.compr_data_size);
556 atomic64_dec(&zram->stats.pages_stored);
558 meta->table[index].handle = 0;
559 zram_set_obj_size(meta, index, 0);
562 static int zram_decompress_page(struct zram *zram, char *mem, u32 index)
564 int ret = 0;
565 unsigned char *cmem;
566 struct zram_meta *meta = zram->meta;
567 unsigned long handle;
568 unsigned int size;
570 bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
571 handle = meta->table[index].handle;
572 size = zram_get_obj_size(meta, index);
574 if (!handle || zram_test_flag(meta, index, ZRAM_ZERO)) {
575 bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
576 clear_page(mem);
577 return 0;
580 cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_RO);
581 if (size == PAGE_SIZE) {
582 copy_page(mem, cmem);
583 } else {
584 struct zcomp_strm *zstrm = zcomp_stream_get(zram->comp);
586 ret = zcomp_decompress(zstrm, cmem, size, mem);
587 zcomp_stream_put(zram->comp);
589 zs_unmap_object(meta->mem_pool, handle);
590 bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
592 /* Should NEVER happen. Return bio error if it does. */
593 if (unlikely(ret)) {
594 pr_err("Decompression failed! err=%d, page=%u\n", ret, index);
595 return ret;
598 return 0;
601 static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
602 u32 index, int offset)
604 int ret;
605 struct page *page;
606 unsigned char *user_mem, *uncmem = NULL;
607 struct zram_meta *meta = zram->meta;
608 page = bvec->bv_page;
610 bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
611 if (unlikely(!meta->table[index].handle) ||
612 zram_test_flag(meta, index, ZRAM_ZERO)) {
613 bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
614 handle_zero_page(bvec);
615 return 0;
617 bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
619 if (is_partial_io(bvec))
620 /* Use a temporary buffer to decompress the page */
621 uncmem = kmalloc(PAGE_SIZE, GFP_NOIO);
623 user_mem = kmap_atomic(page);
624 if (!is_partial_io(bvec))
625 uncmem = user_mem;
627 if (!uncmem) {
628 pr_err("Unable to allocate temp memory\n");
629 ret = -ENOMEM;
630 goto out_cleanup;
633 ret = zram_decompress_page(zram, uncmem, index);
634 /* Should NEVER happen. Return bio error if it does. */
635 if (unlikely(ret))
636 goto out_cleanup;
638 if (is_partial_io(bvec))
639 memcpy(user_mem + bvec->bv_offset, uncmem + offset,
640 bvec->bv_len);
642 flush_dcache_page(page);
643 ret = 0;
644 out_cleanup:
645 kunmap_atomic(user_mem);
646 if (is_partial_io(bvec))
647 kfree(uncmem);
648 return ret;
651 static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
652 int offset)
654 int ret = 0;
655 unsigned int clen;
656 unsigned long handle = 0;
657 struct page *page;
658 unsigned char *user_mem, *cmem, *src, *uncmem = NULL;
659 struct zram_meta *meta = zram->meta;
660 struct zcomp_strm *zstrm = NULL;
661 unsigned long alloced_pages;
663 page = bvec->bv_page;
664 if (is_partial_io(bvec)) {
666 * This is a partial IO. We need to read the full page
667 * before to write the changes.
669 uncmem = kmalloc(PAGE_SIZE, GFP_NOIO);
670 if (!uncmem) {
671 ret = -ENOMEM;
672 goto out;
674 ret = zram_decompress_page(zram, uncmem, index);
675 if (ret)
676 goto out;
679 compress_again:
680 user_mem = kmap_atomic(page);
681 if (is_partial_io(bvec)) {
682 memcpy(uncmem + offset, user_mem + bvec->bv_offset,
683 bvec->bv_len);
684 kunmap_atomic(user_mem);
685 user_mem = NULL;
686 } else {
687 uncmem = user_mem;
690 if (page_zero_filled(uncmem)) {
691 if (user_mem)
692 kunmap_atomic(user_mem);
693 /* Free memory associated with this sector now. */
694 bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
695 zram_free_page(zram, index);
696 zram_set_flag(meta, index, ZRAM_ZERO);
697 bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
699 atomic64_inc(&zram->stats.zero_pages);
700 ret = 0;
701 goto out;
704 zstrm = zcomp_stream_get(zram->comp);
705 ret = zcomp_compress(zstrm, uncmem, &clen);
706 if (!is_partial_io(bvec)) {
707 kunmap_atomic(user_mem);
708 user_mem = NULL;
709 uncmem = NULL;
712 if (unlikely(ret)) {
713 pr_err("Compression failed! err=%d\n", ret);
714 goto out;
717 src = zstrm->buffer;
718 if (unlikely(clen > max_zpage_size)) {
719 clen = PAGE_SIZE;
720 if (is_partial_io(bvec))
721 src = uncmem;
725 * handle allocation has 2 paths:
726 * a) fast path is executed with preemption disabled (for
727 * per-cpu streams) and has __GFP_DIRECT_RECLAIM bit clear,
728 * since we can't sleep;
729 * b) slow path enables preemption and attempts to allocate
730 * the page with __GFP_DIRECT_RECLAIM bit set. we have to
731 * put per-cpu compression stream and, thus, to re-do
732 * the compression once handle is allocated.
734 * if we have a 'non-null' handle here then we are coming
735 * from the slow path and handle has already been allocated.
737 if (!handle)
738 handle = zs_malloc(meta->mem_pool, clen,
739 __GFP_KSWAPD_RECLAIM |
740 __GFP_NOWARN |
741 __GFP_HIGHMEM |
742 __GFP_MOVABLE);
743 if (!handle) {
744 zcomp_stream_put(zram->comp);
745 zstrm = NULL;
747 atomic64_inc(&zram->stats.writestall);
749 handle = zs_malloc(meta->mem_pool, clen,
750 GFP_NOIO | __GFP_HIGHMEM |
751 __GFP_MOVABLE);
752 if (handle)
753 goto compress_again;
755 pr_err("Error allocating memory for compressed page: %u, size=%u\n",
756 index, clen);
757 ret = -ENOMEM;
758 goto out;
761 alloced_pages = zs_get_total_pages(meta->mem_pool);
762 update_used_max(zram, alloced_pages);
764 if (zram->limit_pages && alloced_pages > zram->limit_pages) {
765 zs_free(meta->mem_pool, handle);
766 ret = -ENOMEM;
767 goto out;
770 cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_WO);
772 if ((clen == PAGE_SIZE) && !is_partial_io(bvec)) {
773 src = kmap_atomic(page);
774 copy_page(cmem, src);
775 kunmap_atomic(src);
776 } else {
777 memcpy(cmem, src, clen);
780 zcomp_stream_put(zram->comp);
781 zstrm = NULL;
782 zs_unmap_object(meta->mem_pool, handle);
785 * Free memory associated with this sector
786 * before overwriting unused sectors.
788 bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
789 zram_free_page(zram, index);
791 meta->table[index].handle = handle;
792 zram_set_obj_size(meta, index, clen);
793 bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
795 /* Update stats */
796 atomic64_add(clen, &zram->stats.compr_data_size);
797 atomic64_inc(&zram->stats.pages_stored);
798 out:
799 if (zstrm)
800 zcomp_stream_put(zram->comp);
801 if (is_partial_io(bvec))
802 kfree(uncmem);
803 return ret;
807 * zram_bio_discard - handler on discard request
808 * @index: physical block index in PAGE_SIZE units
809 * @offset: byte offset within physical block
811 static void zram_bio_discard(struct zram *zram, u32 index,
812 int offset, struct bio *bio)
814 size_t n = bio->bi_iter.bi_size;
815 struct zram_meta *meta = zram->meta;
818 * zram manages data in physical block size units. Because logical block
819 * size isn't identical with physical block size on some arch, we
820 * could get a discard request pointing to a specific offset within a
821 * certain physical block. Although we can handle this request by
822 * reading that physiclal block and decompressing and partially zeroing
823 * and re-compressing and then re-storing it, this isn't reasonable
824 * because our intent with a discard request is to save memory. So
825 * skipping this logical block is appropriate here.
827 if (offset) {
828 if (n <= (PAGE_SIZE - offset))
829 return;
831 n -= (PAGE_SIZE - offset);
832 index++;
835 while (n >= PAGE_SIZE) {
836 bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
837 zram_free_page(zram, index);
838 bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
839 atomic64_inc(&zram->stats.notify_free);
840 index++;
841 n -= PAGE_SIZE;
845 static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index,
846 int offset, bool is_write)
848 unsigned long start_time = jiffies;
849 int rw_acct = is_write ? REQ_OP_WRITE : REQ_OP_READ;
850 int ret;
852 generic_start_io_acct(rw_acct, bvec->bv_len >> SECTOR_SHIFT,
853 &zram->disk->part0);
855 if (!is_write) {
856 atomic64_inc(&zram->stats.num_reads);
857 ret = zram_bvec_read(zram, bvec, index, offset);
858 } else {
859 atomic64_inc(&zram->stats.num_writes);
860 ret = zram_bvec_write(zram, bvec, index, offset);
863 generic_end_io_acct(rw_acct, &zram->disk->part0, start_time);
865 if (unlikely(ret)) {
866 if (!is_write)
867 atomic64_inc(&zram->stats.failed_reads);
868 else
869 atomic64_inc(&zram->stats.failed_writes);
872 return ret;
875 static void __zram_make_request(struct zram *zram, struct bio *bio)
877 int offset;
878 u32 index;
879 struct bio_vec bvec;
880 struct bvec_iter iter;
882 index = bio->bi_iter.bi_sector >> SECTORS_PER_PAGE_SHIFT;
883 offset = (bio->bi_iter.bi_sector &
884 (SECTORS_PER_PAGE - 1)) << SECTOR_SHIFT;
886 if (unlikely(bio_op(bio) == REQ_OP_DISCARD)) {
887 zram_bio_discard(zram, index, offset, bio);
888 bio_endio(bio);
889 return;
892 bio_for_each_segment(bvec, bio, iter) {
893 int max_transfer_size = PAGE_SIZE - offset;
895 if (bvec.bv_len > max_transfer_size) {
897 * zram_bvec_rw() can only make operation on a single
898 * zram page. Split the bio vector.
900 struct bio_vec bv;
902 bv.bv_page = bvec.bv_page;
903 bv.bv_len = max_transfer_size;
904 bv.bv_offset = bvec.bv_offset;
906 if (zram_bvec_rw(zram, &bv, index, offset,
907 op_is_write(bio_op(bio))) < 0)
908 goto out;
910 bv.bv_len = bvec.bv_len - max_transfer_size;
911 bv.bv_offset += max_transfer_size;
912 if (zram_bvec_rw(zram, &bv, index + 1, 0,
913 op_is_write(bio_op(bio))) < 0)
914 goto out;
915 } else
916 if (zram_bvec_rw(zram, &bvec, index, offset,
917 op_is_write(bio_op(bio))) < 0)
918 goto out;
920 update_position(&index, &offset, &bvec);
923 bio_endio(bio);
924 return;
926 out:
927 bio_io_error(bio);
931 * Handler function for all zram I/O requests.
933 static blk_qc_t zram_make_request(struct request_queue *queue, struct bio *bio)
935 struct zram *zram = queue->queuedata;
937 if (unlikely(!zram_meta_get(zram)))
938 goto error;
940 blk_queue_split(queue, &bio, queue->bio_split);
942 if (!valid_io_request(zram, bio->bi_iter.bi_sector,
943 bio->bi_iter.bi_size)) {
944 atomic64_inc(&zram->stats.invalid_io);
945 goto put_zram;
948 __zram_make_request(zram, bio);
949 zram_meta_put(zram);
950 return BLK_QC_T_NONE;
951 put_zram:
952 zram_meta_put(zram);
953 error:
954 bio_io_error(bio);
955 return BLK_QC_T_NONE;
958 static void zram_slot_free_notify(struct block_device *bdev,
959 unsigned long index)
961 struct zram *zram;
962 struct zram_meta *meta;
964 zram = bdev->bd_disk->private_data;
965 meta = zram->meta;
967 bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
968 zram_free_page(zram, index);
969 bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
970 atomic64_inc(&zram->stats.notify_free);
973 static int zram_rw_page(struct block_device *bdev, sector_t sector,
974 struct page *page, bool is_write)
976 int offset, err = -EIO;
977 u32 index;
978 struct zram *zram;
979 struct bio_vec bv;
981 zram = bdev->bd_disk->private_data;
982 if (unlikely(!zram_meta_get(zram)))
983 goto out;
985 if (!valid_io_request(zram, sector, PAGE_SIZE)) {
986 atomic64_inc(&zram->stats.invalid_io);
987 err = -EINVAL;
988 goto put_zram;
991 index = sector >> SECTORS_PER_PAGE_SHIFT;
992 offset = sector & (SECTORS_PER_PAGE - 1) << SECTOR_SHIFT;
994 bv.bv_page = page;
995 bv.bv_len = PAGE_SIZE;
996 bv.bv_offset = 0;
998 err = zram_bvec_rw(zram, &bv, index, offset, is_write);
999 put_zram:
1000 zram_meta_put(zram);
1001 out:
1003 * If I/O fails, just return error(ie, non-zero) without
1004 * calling page_endio.
1005 * It causes resubmit the I/O with bio request by upper functions
1006 * of rw_page(e.g., swap_readpage, __swap_writepage) and
1007 * bio->bi_end_io does things to handle the error
1008 * (e.g., SetPageError, set_page_dirty and extra works).
1010 if (err == 0)
1011 page_endio(page, is_write, 0);
1012 return err;
1015 static void zram_reset_device(struct zram *zram)
1017 struct zram_meta *meta;
1018 struct zcomp *comp;
1019 u64 disksize;
1021 down_write(&zram->init_lock);
1023 zram->limit_pages = 0;
1025 if (!init_done(zram)) {
1026 up_write(&zram->init_lock);
1027 return;
1030 meta = zram->meta;
1031 comp = zram->comp;
1032 disksize = zram->disksize;
1034 * Refcount will go down to 0 eventually and r/w handler
1035 * cannot handle further I/O so it will bail out by
1036 * check zram_meta_get.
1038 zram_meta_put(zram);
1040 * We want to free zram_meta in process context to avoid
1041 * deadlock between reclaim path and any other locks.
1043 wait_event(zram->io_done, atomic_read(&zram->refcount) == 0);
1045 /* Reset stats */
1046 memset(&zram->stats, 0, sizeof(zram->stats));
1047 zram->disksize = 0;
1049 set_capacity(zram->disk, 0);
1050 part_stat_set_all(&zram->disk->part0, 0);
1052 up_write(&zram->init_lock);
1053 /* I/O operation under all of CPU are done so let's free */
1054 zram_meta_free(meta, disksize);
1055 zcomp_destroy(comp);
1058 static ssize_t disksize_store(struct device *dev,
1059 struct device_attribute *attr, const char *buf, size_t len)
1061 u64 disksize;
1062 struct zcomp *comp;
1063 struct zram_meta *meta;
1064 struct zram *zram = dev_to_zram(dev);
1065 int err;
1067 disksize = memparse(buf, NULL);
1068 if (!disksize)
1069 return -EINVAL;
1071 disksize = PAGE_ALIGN(disksize);
1072 meta = zram_meta_alloc(zram->disk->disk_name, disksize);
1073 if (!meta)
1074 return -ENOMEM;
1076 comp = zcomp_create(zram->compressor);
1077 if (IS_ERR(comp)) {
1078 pr_err("Cannot initialise %s compressing backend\n",
1079 zram->compressor);
1080 err = PTR_ERR(comp);
1081 goto out_free_meta;
1084 down_write(&zram->init_lock);
1085 if (init_done(zram)) {
1086 pr_info("Cannot change disksize for initialized device\n");
1087 err = -EBUSY;
1088 goto out_destroy_comp;
1091 init_waitqueue_head(&zram->io_done);
1092 atomic_set(&zram->refcount, 1);
1093 zram->meta = meta;
1094 zram->comp = comp;
1095 zram->disksize = disksize;
1096 set_capacity(zram->disk, zram->disksize >> SECTOR_SHIFT);
1097 up_write(&zram->init_lock);
1100 * Revalidate disk out of the init_lock to avoid lockdep splat.
1101 * It's okay because disk's capacity is protected by init_lock
1102 * so that revalidate_disk always sees up-to-date capacity.
1104 revalidate_disk(zram->disk);
1106 return len;
1108 out_destroy_comp:
1109 up_write(&zram->init_lock);
1110 zcomp_destroy(comp);
1111 out_free_meta:
1112 zram_meta_free(meta, disksize);
1113 return err;
1116 static ssize_t reset_store(struct device *dev,
1117 struct device_attribute *attr, const char *buf, size_t len)
1119 int ret;
1120 unsigned short do_reset;
1121 struct zram *zram;
1122 struct block_device *bdev;
1124 ret = kstrtou16(buf, 10, &do_reset);
1125 if (ret)
1126 return ret;
1128 if (!do_reset)
1129 return -EINVAL;
1131 zram = dev_to_zram(dev);
1132 bdev = bdget_disk(zram->disk, 0);
1133 if (!bdev)
1134 return -ENOMEM;
1136 mutex_lock(&bdev->bd_mutex);
1137 /* Do not reset an active device or claimed device */
1138 if (bdev->bd_openers || zram->claim) {
1139 mutex_unlock(&bdev->bd_mutex);
1140 bdput(bdev);
1141 return -EBUSY;
1144 /* From now on, anyone can't open /dev/zram[0-9] */
1145 zram->claim = true;
1146 mutex_unlock(&bdev->bd_mutex);
1148 /* Make sure all the pending I/O are finished */
1149 fsync_bdev(bdev);
1150 zram_reset_device(zram);
1151 revalidate_disk(zram->disk);
1152 bdput(bdev);
1154 mutex_lock(&bdev->bd_mutex);
1155 zram->claim = false;
1156 mutex_unlock(&bdev->bd_mutex);
1158 return len;
1161 static int zram_open(struct block_device *bdev, fmode_t mode)
1163 int ret = 0;
1164 struct zram *zram;
1166 WARN_ON(!mutex_is_locked(&bdev->bd_mutex));
1168 zram = bdev->bd_disk->private_data;
1169 /* zram was claimed to reset so open request fails */
1170 if (zram->claim)
1171 ret = -EBUSY;
1173 return ret;
1176 static const struct block_device_operations zram_devops = {
1177 .open = zram_open,
1178 .swap_slot_free_notify = zram_slot_free_notify,
1179 .rw_page = zram_rw_page,
1180 .owner = THIS_MODULE
1183 static DEVICE_ATTR_WO(compact);
1184 static DEVICE_ATTR_RW(disksize);
1185 static DEVICE_ATTR_RO(initstate);
1186 static DEVICE_ATTR_WO(reset);
1187 static DEVICE_ATTR_RO(orig_data_size);
1188 static DEVICE_ATTR_RO(mem_used_total);
1189 static DEVICE_ATTR_RW(mem_limit);
1190 static DEVICE_ATTR_RW(mem_used_max);
1191 static DEVICE_ATTR_RW(max_comp_streams);
1192 static DEVICE_ATTR_RW(comp_algorithm);
1194 static struct attribute *zram_disk_attrs[] = {
1195 &dev_attr_disksize.attr,
1196 &dev_attr_initstate.attr,
1197 &dev_attr_reset.attr,
1198 &dev_attr_num_reads.attr,
1199 &dev_attr_num_writes.attr,
1200 &dev_attr_failed_reads.attr,
1201 &dev_attr_failed_writes.attr,
1202 &dev_attr_compact.attr,
1203 &dev_attr_invalid_io.attr,
1204 &dev_attr_notify_free.attr,
1205 &dev_attr_zero_pages.attr,
1206 &dev_attr_orig_data_size.attr,
1207 &dev_attr_compr_data_size.attr,
1208 &dev_attr_mem_used_total.attr,
1209 &dev_attr_mem_limit.attr,
1210 &dev_attr_mem_used_max.attr,
1211 &dev_attr_max_comp_streams.attr,
1212 &dev_attr_comp_algorithm.attr,
1213 &dev_attr_io_stat.attr,
1214 &dev_attr_mm_stat.attr,
1215 &dev_attr_debug_stat.attr,
1216 NULL,
1219 static struct attribute_group zram_disk_attr_group = {
1220 .attrs = zram_disk_attrs,
1224 * Allocate and initialize new zram device. the function returns
1225 * '>= 0' device_id upon success, and negative value otherwise.
1227 static int zram_add(void)
1229 struct zram *zram;
1230 struct request_queue *queue;
1231 int ret, device_id;
1233 zram = kzalloc(sizeof(struct zram), GFP_KERNEL);
1234 if (!zram)
1235 return -ENOMEM;
1237 ret = idr_alloc(&zram_index_idr, zram, 0, 0, GFP_KERNEL);
1238 if (ret < 0)
1239 goto out_free_dev;
1240 device_id = ret;
1242 init_rwsem(&zram->init_lock);
1244 queue = blk_alloc_queue(GFP_KERNEL);
1245 if (!queue) {
1246 pr_err("Error allocating disk queue for device %d\n",
1247 device_id);
1248 ret = -ENOMEM;
1249 goto out_free_idr;
1252 blk_queue_make_request(queue, zram_make_request);
1254 /* gendisk structure */
1255 zram->disk = alloc_disk(1);
1256 if (!zram->disk) {
1257 pr_err("Error allocating disk structure for device %d\n",
1258 device_id);
1259 ret = -ENOMEM;
1260 goto out_free_queue;
1263 zram->disk->major = zram_major;
1264 zram->disk->first_minor = device_id;
1265 zram->disk->fops = &zram_devops;
1266 zram->disk->queue = queue;
1267 zram->disk->queue->queuedata = zram;
1268 zram->disk->private_data = zram;
1269 snprintf(zram->disk->disk_name, 16, "zram%d", device_id);
1271 /* Actual capacity set using syfs (/sys/block/zram<id>/disksize */
1272 set_capacity(zram->disk, 0);
1273 /* zram devices sort of resembles non-rotational disks */
1274 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, zram->disk->queue);
1275 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, zram->disk->queue);
1277 * To ensure that we always get PAGE_SIZE aligned
1278 * and n*PAGE_SIZED sized I/O requests.
1280 blk_queue_physical_block_size(zram->disk->queue, PAGE_SIZE);
1281 blk_queue_logical_block_size(zram->disk->queue,
1282 ZRAM_LOGICAL_BLOCK_SIZE);
1283 blk_queue_io_min(zram->disk->queue, PAGE_SIZE);
1284 blk_queue_io_opt(zram->disk->queue, PAGE_SIZE);
1285 zram->disk->queue->limits.discard_granularity = PAGE_SIZE;
1286 blk_queue_max_discard_sectors(zram->disk->queue, UINT_MAX);
1288 * zram_bio_discard() will clear all logical blocks if logical block
1289 * size is identical with physical block size(PAGE_SIZE). But if it is
1290 * different, we will skip discarding some parts of logical blocks in
1291 * the part of the request range which isn't aligned to physical block
1292 * size. So we can't ensure that all discarded logical blocks are
1293 * zeroed.
1295 if (ZRAM_LOGICAL_BLOCK_SIZE == PAGE_SIZE)
1296 zram->disk->queue->limits.discard_zeroes_data = 1;
1297 else
1298 zram->disk->queue->limits.discard_zeroes_data = 0;
1299 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, zram->disk->queue);
1301 add_disk(zram->disk);
1303 ret = sysfs_create_group(&disk_to_dev(zram->disk)->kobj,
1304 &zram_disk_attr_group);
1305 if (ret < 0) {
1306 pr_err("Error creating sysfs group for device %d\n",
1307 device_id);
1308 goto out_free_disk;
1310 strlcpy(zram->compressor, default_compressor, sizeof(zram->compressor));
1311 zram->meta = NULL;
1313 pr_info("Added device: %s\n", zram->disk->disk_name);
1314 return device_id;
1316 out_free_disk:
1317 del_gendisk(zram->disk);
1318 put_disk(zram->disk);
1319 out_free_queue:
1320 blk_cleanup_queue(queue);
1321 out_free_idr:
1322 idr_remove(&zram_index_idr, device_id);
1323 out_free_dev:
1324 kfree(zram);
1325 return ret;
1328 static int zram_remove(struct zram *zram)
1330 struct block_device *bdev;
1332 bdev = bdget_disk(zram->disk, 0);
1333 if (!bdev)
1334 return -ENOMEM;
1336 mutex_lock(&bdev->bd_mutex);
1337 if (bdev->bd_openers || zram->claim) {
1338 mutex_unlock(&bdev->bd_mutex);
1339 bdput(bdev);
1340 return -EBUSY;
1343 zram->claim = true;
1344 mutex_unlock(&bdev->bd_mutex);
1347 * Remove sysfs first, so no one will perform a disksize
1348 * store while we destroy the devices. This also helps during
1349 * hot_remove -- zram_reset_device() is the last holder of
1350 * ->init_lock, no later/concurrent disksize_store() or any
1351 * other sysfs handlers are possible.
1353 sysfs_remove_group(&disk_to_dev(zram->disk)->kobj,
1354 &zram_disk_attr_group);
1356 /* Make sure all the pending I/O are finished */
1357 fsync_bdev(bdev);
1358 zram_reset_device(zram);
1359 bdput(bdev);
1361 pr_info("Removed device: %s\n", zram->disk->disk_name);
1363 blk_cleanup_queue(zram->disk->queue);
1364 del_gendisk(zram->disk);
1365 put_disk(zram->disk);
1366 kfree(zram);
1367 return 0;
1370 /* zram-control sysfs attributes */
1371 static ssize_t hot_add_show(struct class *class,
1372 struct class_attribute *attr,
1373 char *buf)
1375 int ret;
1377 mutex_lock(&zram_index_mutex);
1378 ret = zram_add();
1379 mutex_unlock(&zram_index_mutex);
1381 if (ret < 0)
1382 return ret;
1383 return scnprintf(buf, PAGE_SIZE, "%d\n", ret);
1386 static ssize_t hot_remove_store(struct class *class,
1387 struct class_attribute *attr,
1388 const char *buf,
1389 size_t count)
1391 struct zram *zram;
1392 int ret, dev_id;
1394 /* dev_id is gendisk->first_minor, which is `int' */
1395 ret = kstrtoint(buf, 10, &dev_id);
1396 if (ret)
1397 return ret;
1398 if (dev_id < 0)
1399 return -EINVAL;
1401 mutex_lock(&zram_index_mutex);
1403 zram = idr_find(&zram_index_idr, dev_id);
1404 if (zram) {
1405 ret = zram_remove(zram);
1406 idr_remove(&zram_index_idr, dev_id);
1407 } else {
1408 ret = -ENODEV;
1411 mutex_unlock(&zram_index_mutex);
1412 return ret ? ret : count;
1415 static struct class_attribute zram_control_class_attrs[] = {
1416 __ATTR_RO(hot_add),
1417 __ATTR_WO(hot_remove),
1418 __ATTR_NULL,
1421 static struct class zram_control_class = {
1422 .name = "zram-control",
1423 .owner = THIS_MODULE,
1424 .class_attrs = zram_control_class_attrs,
1427 static int zram_remove_cb(int id, void *ptr, void *data)
1429 zram_remove(ptr);
1430 return 0;
1433 static void destroy_devices(void)
1435 class_unregister(&zram_control_class);
1436 idr_for_each(&zram_index_idr, &zram_remove_cb, NULL);
1437 idr_destroy(&zram_index_idr);
1438 unregister_blkdev(zram_major, "zram");
1441 static int __init zram_init(void)
1443 int ret;
1445 ret = class_register(&zram_control_class);
1446 if (ret) {
1447 pr_err("Unable to register zram-control class\n");
1448 return ret;
1451 zram_major = register_blkdev(0, "zram");
1452 if (zram_major <= 0) {
1453 pr_err("Unable to get major number\n");
1454 class_unregister(&zram_control_class);
1455 return -EBUSY;
1458 while (num_devices != 0) {
1459 mutex_lock(&zram_index_mutex);
1460 ret = zram_add();
1461 mutex_unlock(&zram_index_mutex);
1462 if (ret < 0)
1463 goto out_error;
1464 num_devices--;
1467 return 0;
1469 out_error:
1470 destroy_devices();
1471 return ret;
1474 static void __exit zram_exit(void)
1476 destroy_devices();
1479 module_init(zram_init);
1480 module_exit(zram_exit);
1482 module_param(num_devices, uint, 0);
1483 MODULE_PARM_DESC(num_devices, "Number of pre-created zram devices");
1485 MODULE_LICENSE("Dual BSD/GPL");
1486 MODULE_AUTHOR("Nitin Gupta <ngupta@vflare.org>");
1487 MODULE_DESCRIPTION("Compressed RAM Block Device");