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>
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",
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) \
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)); \
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 int 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 int valid_io_request(struct zram
*zram
,
118 sector_t start
, unsigned int size
)
122 /* unaligned request */
123 if (unlikely(start
& (ZRAM_SECTOR_PER_LOGICAL_BLOCK
- 1)))
125 if (unlikely(size
& (ZRAM_LOGICAL_BLOCK_SIZE
- 1)))
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
))
134 /* I/O request is valid */
138 static void update_position(u32
*index
, int *offset
, struct bio_vec
*bvec
)
140 if (*offset
+ bvec
->bv_len
>= PAGE_SIZE
)
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
);
155 old_max
= atomic_long_cmpxchg(
156 &zram
->stats
.max_used_pages
, cur_max
, pages
);
157 } while (old_max
!= cur_max
);
160 static int page_zero_filled(void *ptr
)
165 page
= (unsigned long *)ptr
;
167 for (pos
= 0; pos
!= PAGE_SIZE
/ sizeof(*page
); pos
++) {
175 static void handle_zero_page(struct bio_vec
*bvec
)
177 struct page
*page
= bvec
->bv_page
;
180 user_mem
= kmap_atomic(page
);
181 if (is_partial_io(bvec
))
182 memset(user_mem
+ bvec
->bv_offset
, 0, bvec
->bv_len
);
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
)
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
)
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
)
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
)
257 struct zram
*zram
= dev_to_zram(dev
);
259 limit
= memparse(buf
, &tmp
);
260 if (buf
== tmp
) /* no chars parsed, invalid input */
263 down_write(&zram
->init_lock
);
264 zram
->limit_pages
= PAGE_ALIGN(limit
) >> PAGE_SHIFT
;
265 up_write(&zram
->init_lock
);
270 static ssize_t
mem_used_max_show(struct device
*dev
,
271 struct device_attribute
*attr
, char *buf
)
274 struct zram
*zram
= dev_to_zram(dev
);
276 deprecated_attr_warn("mem_used_max");
277 down_read(&zram
->init_lock
);
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
)
290 struct zram
*zram
= dev_to_zram(dev
);
292 err
= kstrtoul(buf
, 10, &val
);
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
);
307 static ssize_t
max_comp_streams_show(struct device
*dev
,
308 struct device_attribute
*attr
, char *buf
)
311 struct zram
*zram
= dev_to_zram(dev
);
313 down_read(&zram
->init_lock
);
314 val
= zram
->max_comp_streams
;
315 up_read(&zram
->init_lock
);
317 return scnprintf(buf
, PAGE_SIZE
, "%d\n", val
);
320 static ssize_t
max_comp_streams_store(struct device
*dev
,
321 struct device_attribute
*attr
, const char *buf
, size_t len
)
324 struct zram
*zram
= dev_to_zram(dev
);
327 ret
= kstrtoint(buf
, 0, &num
);
333 down_write(&zram
->init_lock
);
334 if (init_done(zram
)) {
335 if (!zcomp_set_max_streams(zram
->comp
, num
)) {
336 pr_info("Cannot change max compression streams\n");
342 zram
->max_comp_streams
= num
;
345 up_write(&zram
->init_lock
);
349 static ssize_t
comp_algorithm_show(struct device
*dev
,
350 struct device_attribute
*attr
, char *buf
)
353 struct zram
*zram
= dev_to_zram(dev
);
355 down_read(&zram
->init_lock
);
356 sz
= zcomp_available_show(zram
->compressor
, buf
);
357 up_read(&zram
->init_lock
);
362 static ssize_t
comp_algorithm_store(struct device
*dev
,
363 struct device_attribute
*attr
, const char *buf
, size_t len
)
365 struct zram
*zram
= dev_to_zram(dev
);
368 down_write(&zram
->init_lock
);
369 if (init_done(zram
)) {
370 up_write(&zram
->init_lock
);
371 pr_info("Can't change algorithm for initialized device\n");
374 strlcpy(zram
->compressor
, buf
, sizeof(zram
->compressor
));
376 /* ignore trailing newline */
377 sz
= strlen(zram
->compressor
);
378 if (sz
> 0 && zram
->compressor
[sz
- 1] == '\n')
379 zram
->compressor
[sz
- 1] = 0x00;
381 if (!zcomp_available_algorithm(zram
->compressor
))
384 up_write(&zram
->init_lock
);
388 static ssize_t
compact_store(struct device
*dev
,
389 struct device_attribute
*attr
, const char *buf
, size_t len
)
391 unsigned long nr_migrated
;
392 struct zram
*zram
= dev_to_zram(dev
);
393 struct zram_meta
*meta
;
395 down_read(&zram
->init_lock
);
396 if (!init_done(zram
)) {
397 up_read(&zram
->init_lock
);
402 nr_migrated
= zs_compact(meta
->mem_pool
);
403 atomic64_add(nr_migrated
, &zram
->stats
.num_migrated
);
404 up_read(&zram
->init_lock
);
409 static ssize_t
io_stat_show(struct device
*dev
,
410 struct device_attribute
*attr
, char *buf
)
412 struct zram
*zram
= dev_to_zram(dev
);
415 down_read(&zram
->init_lock
);
416 ret
= scnprintf(buf
, PAGE_SIZE
,
417 "%8llu %8llu %8llu %8llu\n",
418 (u64
)atomic64_read(&zram
->stats
.failed_reads
),
419 (u64
)atomic64_read(&zram
->stats
.failed_writes
),
420 (u64
)atomic64_read(&zram
->stats
.invalid_io
),
421 (u64
)atomic64_read(&zram
->stats
.notify_free
));
422 up_read(&zram
->init_lock
);
427 static ssize_t
mm_stat_show(struct device
*dev
,
428 struct device_attribute
*attr
, char *buf
)
430 struct zram
*zram
= dev_to_zram(dev
);
431 u64 orig_size
, mem_used
= 0;
435 down_read(&zram
->init_lock
);
437 mem_used
= zs_get_total_pages(zram
->meta
->mem_pool
);
439 orig_size
= atomic64_read(&zram
->stats
.pages_stored
);
440 max_used
= atomic_long_read(&zram
->stats
.max_used_pages
);
442 ret
= scnprintf(buf
, PAGE_SIZE
,
443 "%8llu %8llu %8llu %8lu %8ld %8llu %8llu\n",
444 orig_size
<< PAGE_SHIFT
,
445 (u64
)atomic64_read(&zram
->stats
.compr_data_size
),
446 mem_used
<< PAGE_SHIFT
,
447 zram
->limit_pages
<< PAGE_SHIFT
,
448 max_used
<< PAGE_SHIFT
,
449 (u64
)atomic64_read(&zram
->stats
.zero_pages
),
450 (u64
)atomic64_read(&zram
->stats
.num_migrated
));
451 up_read(&zram
->init_lock
);
456 static DEVICE_ATTR_RO(io_stat
);
457 static DEVICE_ATTR_RO(mm_stat
);
458 ZRAM_ATTR_RO(num_reads
);
459 ZRAM_ATTR_RO(num_writes
);
460 ZRAM_ATTR_RO(failed_reads
);
461 ZRAM_ATTR_RO(failed_writes
);
462 ZRAM_ATTR_RO(invalid_io
);
463 ZRAM_ATTR_RO(notify_free
);
464 ZRAM_ATTR_RO(zero_pages
);
465 ZRAM_ATTR_RO(compr_data_size
);
467 static inline bool zram_meta_get(struct zram
*zram
)
469 if (atomic_inc_not_zero(&zram
->refcount
))
474 static inline void zram_meta_put(struct zram
*zram
)
476 atomic_dec(&zram
->refcount
);
479 static void zram_meta_free(struct zram_meta
*meta
, u64 disksize
)
481 size_t num_pages
= disksize
>> PAGE_SHIFT
;
484 /* Free all pages that are still in this zram device */
485 for (index
= 0; index
< num_pages
; index
++) {
486 unsigned long handle
= meta
->table
[index
].handle
;
491 zs_free(meta
->mem_pool
, handle
);
494 zs_destroy_pool(meta
->mem_pool
);
499 static struct zram_meta
*zram_meta_alloc(int device_id
, u64 disksize
)
503 struct zram_meta
*meta
= kmalloc(sizeof(*meta
), GFP_KERNEL
);
508 num_pages
= disksize
>> PAGE_SHIFT
;
509 meta
->table
= vzalloc(num_pages
* sizeof(*meta
->table
));
511 pr_err("Error allocating zram address table\n");
515 snprintf(pool_name
, sizeof(pool_name
), "zram%d", device_id
);
516 meta
->mem_pool
= zs_create_pool(pool_name
, GFP_NOIO
| __GFP_HIGHMEM
);
517 if (!meta
->mem_pool
) {
518 pr_err("Error creating memory pool\n");
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
);
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
)
566 struct zram_meta
*meta
= zram
->meta
;
567 unsigned long handle
;
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
);
580 cmem
= zs_map_object(meta
->mem_pool
, handle
, ZS_MM_RO
);
581 if (size
== PAGE_SIZE
)
582 copy_page(mem
, cmem
);
584 ret
= zcomp_decompress(zram
->comp
, cmem
, size
, mem
);
585 zs_unmap_object(meta
->mem_pool
, handle
);
586 bit_spin_unlock(ZRAM_ACCESS
, &meta
->table
[index
].value
);
588 /* Should NEVER happen. Return bio error if it does. */
590 pr_err("Decompression failed! err=%d, page=%u\n", ret
, index
);
597 static int zram_bvec_read(struct zram
*zram
, struct bio_vec
*bvec
,
598 u32 index
, int offset
)
602 unsigned char *user_mem
, *uncmem
= NULL
;
603 struct zram_meta
*meta
= zram
->meta
;
604 page
= bvec
->bv_page
;
606 bit_spin_lock(ZRAM_ACCESS
, &meta
->table
[index
].value
);
607 if (unlikely(!meta
->table
[index
].handle
) ||
608 zram_test_flag(meta
, index
, ZRAM_ZERO
)) {
609 bit_spin_unlock(ZRAM_ACCESS
, &meta
->table
[index
].value
);
610 handle_zero_page(bvec
);
613 bit_spin_unlock(ZRAM_ACCESS
, &meta
->table
[index
].value
);
615 if (is_partial_io(bvec
))
616 /* Use a temporary buffer to decompress the page */
617 uncmem
= kmalloc(PAGE_SIZE
, GFP_NOIO
);
619 user_mem
= kmap_atomic(page
);
620 if (!is_partial_io(bvec
))
624 pr_info("Unable to allocate temp memory\n");
629 ret
= zram_decompress_page(zram
, uncmem
, index
);
630 /* Should NEVER happen. Return bio error if it does. */
634 if (is_partial_io(bvec
))
635 memcpy(user_mem
+ bvec
->bv_offset
, uncmem
+ offset
,
638 flush_dcache_page(page
);
641 kunmap_atomic(user_mem
);
642 if (is_partial_io(bvec
))
647 static int zram_bvec_write(struct zram
*zram
, struct bio_vec
*bvec
, u32 index
,
652 unsigned long handle
;
654 unsigned char *user_mem
, *cmem
, *src
, *uncmem
= NULL
;
655 struct zram_meta
*meta
= zram
->meta
;
656 struct zcomp_strm
*zstrm
= NULL
;
657 unsigned long alloced_pages
;
659 page
= bvec
->bv_page
;
660 if (is_partial_io(bvec
)) {
662 * This is a partial IO. We need to read the full page
663 * before to write the changes.
665 uncmem
= kmalloc(PAGE_SIZE
, GFP_NOIO
);
670 ret
= zram_decompress_page(zram
, uncmem
, index
);
675 zstrm
= zcomp_strm_find(zram
->comp
);
676 user_mem
= kmap_atomic(page
);
678 if (is_partial_io(bvec
)) {
679 memcpy(uncmem
+ offset
, user_mem
+ bvec
->bv_offset
,
681 kunmap_atomic(user_mem
);
687 if (page_zero_filled(uncmem
)) {
689 kunmap_atomic(user_mem
);
690 /* Free memory associated with this sector now. */
691 bit_spin_lock(ZRAM_ACCESS
, &meta
->table
[index
].value
);
692 zram_free_page(zram
, index
);
693 zram_set_flag(meta
, index
, ZRAM_ZERO
);
694 bit_spin_unlock(ZRAM_ACCESS
, &meta
->table
[index
].value
);
696 atomic64_inc(&zram
->stats
.zero_pages
);
701 ret
= zcomp_compress(zram
->comp
, zstrm
, uncmem
, &clen
);
702 if (!is_partial_io(bvec
)) {
703 kunmap_atomic(user_mem
);
709 pr_err("Compression failed! err=%d\n", ret
);
713 if (unlikely(clen
> max_zpage_size
)) {
715 if (is_partial_io(bvec
))
719 handle
= zs_malloc(meta
->mem_pool
, clen
);
721 pr_info("Error allocating memory for compressed page: %u, size=%zu\n",
727 alloced_pages
= zs_get_total_pages(meta
->mem_pool
);
728 if (zram
->limit_pages
&& alloced_pages
> zram
->limit_pages
) {
729 zs_free(meta
->mem_pool
, handle
);
734 update_used_max(zram
, alloced_pages
);
736 cmem
= zs_map_object(meta
->mem_pool
, handle
, ZS_MM_WO
);
738 if ((clen
== PAGE_SIZE
) && !is_partial_io(bvec
)) {
739 src
= kmap_atomic(page
);
740 copy_page(cmem
, src
);
743 memcpy(cmem
, src
, clen
);
746 zcomp_strm_release(zram
->comp
, zstrm
);
748 zs_unmap_object(meta
->mem_pool
, handle
);
751 * Free memory associated with this sector
752 * before overwriting unused sectors.
754 bit_spin_lock(ZRAM_ACCESS
, &meta
->table
[index
].value
);
755 zram_free_page(zram
, index
);
757 meta
->table
[index
].handle
= handle
;
758 zram_set_obj_size(meta
, index
, clen
);
759 bit_spin_unlock(ZRAM_ACCESS
, &meta
->table
[index
].value
);
762 atomic64_add(clen
, &zram
->stats
.compr_data_size
);
763 atomic64_inc(&zram
->stats
.pages_stored
);
766 zcomp_strm_release(zram
->comp
, zstrm
);
767 if (is_partial_io(bvec
))
773 * zram_bio_discard - handler on discard request
774 * @index: physical block index in PAGE_SIZE units
775 * @offset: byte offset within physical block
777 static void zram_bio_discard(struct zram
*zram
, u32 index
,
778 int offset
, struct bio
*bio
)
780 size_t n
= bio
->bi_iter
.bi_size
;
781 struct zram_meta
*meta
= zram
->meta
;
784 * zram manages data in physical block size units. Because logical block
785 * size isn't identical with physical block size on some arch, we
786 * could get a discard request pointing to a specific offset within a
787 * certain physical block. Although we can handle this request by
788 * reading that physiclal block and decompressing and partially zeroing
789 * and re-compressing and then re-storing it, this isn't reasonable
790 * because our intent with a discard request is to save memory. So
791 * skipping this logical block is appropriate here.
794 if (n
<= (PAGE_SIZE
- offset
))
797 n
-= (PAGE_SIZE
- offset
);
801 while (n
>= PAGE_SIZE
) {
802 bit_spin_lock(ZRAM_ACCESS
, &meta
->table
[index
].value
);
803 zram_free_page(zram
, index
);
804 bit_spin_unlock(ZRAM_ACCESS
, &meta
->table
[index
].value
);
805 atomic64_inc(&zram
->stats
.notify_free
);
811 static int zram_bvec_rw(struct zram
*zram
, struct bio_vec
*bvec
, u32 index
,
814 unsigned long start_time
= jiffies
;
817 generic_start_io_acct(rw
, bvec
->bv_len
>> SECTOR_SHIFT
,
821 atomic64_inc(&zram
->stats
.num_reads
);
822 ret
= zram_bvec_read(zram
, bvec
, index
, offset
);
824 atomic64_inc(&zram
->stats
.num_writes
);
825 ret
= zram_bvec_write(zram
, bvec
, index
, offset
);
828 generic_end_io_acct(rw
, &zram
->disk
->part0
, start_time
);
832 atomic64_inc(&zram
->stats
.failed_reads
);
834 atomic64_inc(&zram
->stats
.failed_writes
);
840 static void __zram_make_request(struct zram
*zram
, struct bio
*bio
)
845 struct bvec_iter iter
;
847 index
= bio
->bi_iter
.bi_sector
>> SECTORS_PER_PAGE_SHIFT
;
848 offset
= (bio
->bi_iter
.bi_sector
&
849 (SECTORS_PER_PAGE
- 1)) << SECTOR_SHIFT
;
851 if (unlikely(bio
->bi_rw
& REQ_DISCARD
)) {
852 zram_bio_discard(zram
, index
, offset
, bio
);
857 rw
= bio_data_dir(bio
);
858 bio_for_each_segment(bvec
, bio
, iter
) {
859 int max_transfer_size
= PAGE_SIZE
- offset
;
861 if (bvec
.bv_len
> max_transfer_size
) {
863 * zram_bvec_rw() can only make operation on a single
864 * zram page. Split the bio vector.
868 bv
.bv_page
= bvec
.bv_page
;
869 bv
.bv_len
= max_transfer_size
;
870 bv
.bv_offset
= bvec
.bv_offset
;
872 if (zram_bvec_rw(zram
, &bv
, index
, offset
, rw
) < 0)
875 bv
.bv_len
= bvec
.bv_len
- max_transfer_size
;
876 bv
.bv_offset
+= max_transfer_size
;
877 if (zram_bvec_rw(zram
, &bv
, index
+ 1, 0, rw
) < 0)
880 if (zram_bvec_rw(zram
, &bvec
, index
, offset
, rw
) < 0)
883 update_position(&index
, &offset
, &bvec
);
886 set_bit(BIO_UPTODATE
, &bio
->bi_flags
);
895 * Handler function for all zram I/O requests.
897 static void zram_make_request(struct request_queue
*queue
, struct bio
*bio
)
899 struct zram
*zram
= queue
->queuedata
;
901 if (unlikely(!zram_meta_get(zram
)))
904 if (!valid_io_request(zram
, bio
->bi_iter
.bi_sector
,
905 bio
->bi_iter
.bi_size
)) {
906 atomic64_inc(&zram
->stats
.invalid_io
);
910 __zram_make_request(zram
, bio
);
919 static void zram_slot_free_notify(struct block_device
*bdev
,
923 struct zram_meta
*meta
;
925 zram
= bdev
->bd_disk
->private_data
;
928 bit_spin_lock(ZRAM_ACCESS
, &meta
->table
[index
].value
);
929 zram_free_page(zram
, index
);
930 bit_spin_unlock(ZRAM_ACCESS
, &meta
->table
[index
].value
);
931 atomic64_inc(&zram
->stats
.notify_free
);
934 static int zram_rw_page(struct block_device
*bdev
, sector_t sector
,
935 struct page
*page
, int rw
)
937 int offset
, err
= -EIO
;
942 zram
= bdev
->bd_disk
->private_data
;
943 if (unlikely(!zram_meta_get(zram
)))
946 if (!valid_io_request(zram
, sector
, PAGE_SIZE
)) {
947 atomic64_inc(&zram
->stats
.invalid_io
);
952 index
= sector
>> SECTORS_PER_PAGE_SHIFT
;
953 offset
= sector
& (SECTORS_PER_PAGE
- 1) << SECTOR_SHIFT
;
956 bv
.bv_len
= PAGE_SIZE
;
959 err
= zram_bvec_rw(zram
, &bv
, index
, offset
, rw
);
964 * If I/O fails, just return error(ie, non-zero) without
965 * calling page_endio.
966 * It causes resubmit the I/O with bio request by upper functions
967 * of rw_page(e.g., swap_readpage, __swap_writepage) and
968 * bio->bi_end_io does things to handle the error
969 * (e.g., SetPageError, set_page_dirty and extra works).
972 page_endio(page
, rw
, 0);
976 static void zram_reset_device(struct zram
*zram
)
978 struct zram_meta
*meta
;
982 down_write(&zram
->init_lock
);
984 zram
->limit_pages
= 0;
986 if (!init_done(zram
)) {
987 up_write(&zram
->init_lock
);
993 disksize
= zram
->disksize
;
995 * Refcount will go down to 0 eventually and r/w handler
996 * cannot handle further I/O so it will bail out by
997 * check zram_meta_get.
1001 * We want to free zram_meta in process context to avoid
1002 * deadlock between reclaim path and any other locks.
1004 wait_event(zram
->io_done
, atomic_read(&zram
->refcount
) == 0);
1007 memset(&zram
->stats
, 0, sizeof(zram
->stats
));
1009 zram
->max_comp_streams
= 1;
1011 set_capacity(zram
->disk
, 0);
1012 part_stat_set_all(&zram
->disk
->part0
, 0);
1014 up_write(&zram
->init_lock
);
1015 /* I/O operation under all of CPU are done so let's free */
1016 zram_meta_free(meta
, disksize
);
1017 zcomp_destroy(comp
);
1020 static ssize_t
disksize_store(struct device
*dev
,
1021 struct device_attribute
*attr
, const char *buf
, size_t len
)
1025 struct zram_meta
*meta
;
1026 struct zram
*zram
= dev_to_zram(dev
);
1029 disksize
= memparse(buf
, NULL
);
1033 disksize
= PAGE_ALIGN(disksize
);
1034 meta
= zram_meta_alloc(zram
->disk
->first_minor
, disksize
);
1038 comp
= zcomp_create(zram
->compressor
, zram
->max_comp_streams
);
1040 pr_info("Cannot initialise %s compressing backend\n",
1042 err
= PTR_ERR(comp
);
1046 down_write(&zram
->init_lock
);
1047 if (init_done(zram
)) {
1048 pr_info("Cannot change disksize for initialized device\n");
1050 goto out_destroy_comp
;
1053 init_waitqueue_head(&zram
->io_done
);
1054 atomic_set(&zram
->refcount
, 1);
1057 zram
->disksize
= disksize
;
1058 set_capacity(zram
->disk
, zram
->disksize
>> SECTOR_SHIFT
);
1059 up_write(&zram
->init_lock
);
1062 * Revalidate disk out of the init_lock to avoid lockdep splat.
1063 * It's okay because disk's capacity is protected by init_lock
1064 * so that revalidate_disk always sees up-to-date capacity.
1066 revalidate_disk(zram
->disk
);
1071 up_write(&zram
->init_lock
);
1072 zcomp_destroy(comp
);
1074 zram_meta_free(meta
, disksize
);
1078 static ssize_t
reset_store(struct device
*dev
,
1079 struct device_attribute
*attr
, const char *buf
, size_t len
)
1082 unsigned short do_reset
;
1084 struct block_device
*bdev
;
1086 ret
= kstrtou16(buf
, 10, &do_reset
);
1093 zram
= dev_to_zram(dev
);
1094 bdev
= bdget_disk(zram
->disk
, 0);
1098 mutex_lock(&bdev
->bd_mutex
);
1099 /* Do not reset an active device or claimed device */
1100 if (bdev
->bd_openers
|| zram
->claim
) {
1101 mutex_unlock(&bdev
->bd_mutex
);
1106 /* From now on, anyone can't open /dev/zram[0-9] */
1108 mutex_unlock(&bdev
->bd_mutex
);
1110 /* Make sure all the pending I/O are finished */
1112 zram_reset_device(zram
);
1113 revalidate_disk(zram
->disk
);
1116 mutex_lock(&bdev
->bd_mutex
);
1117 zram
->claim
= false;
1118 mutex_unlock(&bdev
->bd_mutex
);
1123 static int zram_open(struct block_device
*bdev
, fmode_t mode
)
1128 WARN_ON(!mutex_is_locked(&bdev
->bd_mutex
));
1130 zram
= bdev
->bd_disk
->private_data
;
1131 /* zram was claimed to reset so open request fails */
1138 static const struct block_device_operations zram_devops
= {
1140 .swap_slot_free_notify
= zram_slot_free_notify
,
1141 .rw_page
= zram_rw_page
,
1142 .owner
= THIS_MODULE
1145 static DEVICE_ATTR_WO(compact
);
1146 static DEVICE_ATTR_RW(disksize
);
1147 static DEVICE_ATTR_RO(initstate
);
1148 static DEVICE_ATTR_WO(reset
);
1149 static DEVICE_ATTR_RO(orig_data_size
);
1150 static DEVICE_ATTR_RO(mem_used_total
);
1151 static DEVICE_ATTR_RW(mem_limit
);
1152 static DEVICE_ATTR_RW(mem_used_max
);
1153 static DEVICE_ATTR_RW(max_comp_streams
);
1154 static DEVICE_ATTR_RW(comp_algorithm
);
1156 static struct attribute
*zram_disk_attrs
[] = {
1157 &dev_attr_disksize
.attr
,
1158 &dev_attr_initstate
.attr
,
1159 &dev_attr_reset
.attr
,
1160 &dev_attr_num_reads
.attr
,
1161 &dev_attr_num_writes
.attr
,
1162 &dev_attr_failed_reads
.attr
,
1163 &dev_attr_failed_writes
.attr
,
1164 &dev_attr_compact
.attr
,
1165 &dev_attr_invalid_io
.attr
,
1166 &dev_attr_notify_free
.attr
,
1167 &dev_attr_zero_pages
.attr
,
1168 &dev_attr_orig_data_size
.attr
,
1169 &dev_attr_compr_data_size
.attr
,
1170 &dev_attr_mem_used_total
.attr
,
1171 &dev_attr_mem_limit
.attr
,
1172 &dev_attr_mem_used_max
.attr
,
1173 &dev_attr_max_comp_streams
.attr
,
1174 &dev_attr_comp_algorithm
.attr
,
1175 &dev_attr_io_stat
.attr
,
1176 &dev_attr_mm_stat
.attr
,
1180 static struct attribute_group zram_disk_attr_group
= {
1181 .attrs
= zram_disk_attrs
,
1185 * Allocate and initialize new zram device. the function returns
1186 * '>= 0' device_id upon success, and negative value otherwise.
1188 static int zram_add(void)
1191 struct request_queue
*queue
;
1194 zram
= kzalloc(sizeof(struct zram
), GFP_KERNEL
);
1198 ret
= idr_alloc(&zram_index_idr
, zram
, 0, 0, GFP_KERNEL
);
1203 init_rwsem(&zram
->init_lock
);
1205 queue
= blk_alloc_queue(GFP_KERNEL
);
1207 pr_err("Error allocating disk queue for device %d\n",
1213 blk_queue_make_request(queue
, zram_make_request
);
1215 /* gendisk structure */
1216 zram
->disk
= alloc_disk(1);
1218 pr_warn("Error allocating disk structure for device %d\n",
1221 goto out_free_queue
;
1224 zram
->disk
->major
= zram_major
;
1225 zram
->disk
->first_minor
= device_id
;
1226 zram
->disk
->fops
= &zram_devops
;
1227 zram
->disk
->queue
= queue
;
1228 zram
->disk
->queue
->queuedata
= zram
;
1229 zram
->disk
->private_data
= zram
;
1230 snprintf(zram
->disk
->disk_name
, 16, "zram%d", device_id
);
1232 /* Actual capacity set using syfs (/sys/block/zram<id>/disksize */
1233 set_capacity(zram
->disk
, 0);
1234 /* zram devices sort of resembles non-rotational disks */
1235 queue_flag_set_unlocked(QUEUE_FLAG_NONROT
, zram
->disk
->queue
);
1236 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM
, zram
->disk
->queue
);
1238 * To ensure that we always get PAGE_SIZE aligned
1239 * and n*PAGE_SIZED sized I/O requests.
1241 blk_queue_physical_block_size(zram
->disk
->queue
, PAGE_SIZE
);
1242 blk_queue_logical_block_size(zram
->disk
->queue
,
1243 ZRAM_LOGICAL_BLOCK_SIZE
);
1244 blk_queue_io_min(zram
->disk
->queue
, PAGE_SIZE
);
1245 blk_queue_io_opt(zram
->disk
->queue
, PAGE_SIZE
);
1246 zram
->disk
->queue
->limits
.discard_granularity
= PAGE_SIZE
;
1247 zram
->disk
->queue
->limits
.max_discard_sectors
= UINT_MAX
;
1249 * zram_bio_discard() will clear all logical blocks if logical block
1250 * size is identical with physical block size(PAGE_SIZE). But if it is
1251 * different, we will skip discarding some parts of logical blocks in
1252 * the part of the request range which isn't aligned to physical block
1253 * size. So we can't ensure that all discarded logical blocks are
1256 if (ZRAM_LOGICAL_BLOCK_SIZE
== PAGE_SIZE
)
1257 zram
->disk
->queue
->limits
.discard_zeroes_data
= 1;
1259 zram
->disk
->queue
->limits
.discard_zeroes_data
= 0;
1260 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD
, zram
->disk
->queue
);
1262 add_disk(zram
->disk
);
1264 ret
= sysfs_create_group(&disk_to_dev(zram
->disk
)->kobj
,
1265 &zram_disk_attr_group
);
1267 pr_warn("Error creating sysfs group");
1270 strlcpy(zram
->compressor
, default_compressor
, sizeof(zram
->compressor
));
1272 zram
->max_comp_streams
= 1;
1274 pr_info("Added device: %s\n", zram
->disk
->disk_name
);
1278 del_gendisk(zram
->disk
);
1279 put_disk(zram
->disk
);
1281 blk_cleanup_queue(queue
);
1283 idr_remove(&zram_index_idr
, device_id
);
1289 static int zram_remove(struct zram
*zram
)
1291 struct block_device
*bdev
;
1293 bdev
= bdget_disk(zram
->disk
, 0);
1297 mutex_lock(&bdev
->bd_mutex
);
1298 if (bdev
->bd_openers
|| zram
->claim
) {
1299 mutex_unlock(&bdev
->bd_mutex
);
1305 mutex_unlock(&bdev
->bd_mutex
);
1308 * Remove sysfs first, so no one will perform a disksize
1309 * store while we destroy the devices. This also helps during
1310 * hot_remove -- zram_reset_device() is the last holder of
1311 * ->init_lock, no later/concurrent disksize_store() or any
1312 * other sysfs handlers are possible.
1314 sysfs_remove_group(&disk_to_dev(zram
->disk
)->kobj
,
1315 &zram_disk_attr_group
);
1317 /* Make sure all the pending I/O are finished */
1319 zram_reset_device(zram
);
1322 pr_info("Removed device: %s\n", zram
->disk
->disk_name
);
1324 idr_remove(&zram_index_idr
, zram
->disk
->first_minor
);
1325 blk_cleanup_queue(zram
->disk
->queue
);
1326 del_gendisk(zram
->disk
);
1327 put_disk(zram
->disk
);
1332 /* zram-control sysfs attributes */
1333 static ssize_t
hot_add_show(struct class *class,
1334 struct class_attribute
*attr
,
1339 mutex_lock(&zram_index_mutex
);
1341 mutex_unlock(&zram_index_mutex
);
1345 return scnprintf(buf
, PAGE_SIZE
, "%d\n", ret
);
1348 static ssize_t
hot_remove_store(struct class *class,
1349 struct class_attribute
*attr
,
1356 /* dev_id is gendisk->first_minor, which is `int' */
1357 ret
= kstrtoint(buf
, 10, &dev_id
);
1363 mutex_lock(&zram_index_mutex
);
1365 zram
= idr_find(&zram_index_idr
, dev_id
);
1367 ret
= zram_remove(zram
);
1371 mutex_unlock(&zram_index_mutex
);
1372 return ret
? ret
: count
;
1375 static struct class_attribute zram_control_class_attrs
[] = {
1377 __ATTR_WO(hot_remove
),
1381 static struct class zram_control_class
= {
1382 .name
= "zram-control",
1383 .owner
= THIS_MODULE
,
1384 .class_attrs
= zram_control_class_attrs
,
1387 static int zram_remove_cb(int id
, void *ptr
, void *data
)
1393 static void destroy_devices(void)
1395 class_unregister(&zram_control_class
);
1396 idr_for_each(&zram_index_idr
, &zram_remove_cb
, NULL
);
1397 idr_destroy(&zram_index_idr
);
1398 unregister_blkdev(zram_major
, "zram");
1401 static int __init
zram_init(void)
1405 ret
= class_register(&zram_control_class
);
1407 pr_warn("Unable to register zram-control class\n");
1411 zram_major
= register_blkdev(0, "zram");
1412 if (zram_major
<= 0) {
1413 pr_warn("Unable to get major number\n");
1414 class_unregister(&zram_control_class
);
1418 while (num_devices
!= 0) {
1419 mutex_lock(&zram_index_mutex
);
1421 mutex_unlock(&zram_index_mutex
);
1434 static void __exit
zram_exit(void)
1439 module_init(zram_init
);
1440 module_exit(zram_exit
);
1442 module_param(num_devices
, uint
, 0);
1443 MODULE_PARM_DESC(num_devices
, "Number of pre-created zram devices");
1445 MODULE_LICENSE("Dual BSD/GPL");
1446 MODULE_AUTHOR("Nitin Gupta <ngupta@vflare.org>");
1447 MODULE_DESCRIPTION("Compressed RAM Block Device");