2 * Compressed RAM block device
4 * Copyright (C) 2008, 2009, 2010 Nitin Gupta
6 * This code is released using a dual license strategy: BSD/GPL
7 * You can choose the licence that better fits your requirements.
9 * Released under the terms of 3-clause BSD License
10 * Released under the terms of GNU General Public License Version 2.0
12 * Project home: http://compcache.googlecode.com
15 #define KMSG_COMPONENT "zram"
16 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
18 #ifdef CONFIG_ZRAM_DEBUG
22 #include <linux/module.h>
23 #include <linux/kernel.h>
24 #include <linux/bio.h>
25 #include <linux/bitops.h>
26 #include <linux/blkdev.h>
27 #include <linux/buffer_head.h>
28 #include <linux/device.h>
29 #include <linux/genhd.h>
30 #include <linux/highmem.h>
31 #include <linux/slab.h>
32 #include <linux/lzo.h>
33 #include <linux/string.h>
34 #include <linux/vmalloc.h>
39 static int zram_major
;
40 static struct zram
*zram_devices
;
42 /* Module params (documentation at end) */
43 static unsigned int num_devices
= 1;
45 static inline struct zram
*dev_to_zram(struct device
*dev
)
47 return (struct zram
*)dev_to_disk(dev
)->private_data
;
50 static ssize_t
disksize_show(struct device
*dev
,
51 struct device_attribute
*attr
, char *buf
)
53 struct zram
*zram
= dev_to_zram(dev
);
55 return sprintf(buf
, "%llu\n", zram
->disksize
);
58 static ssize_t
initstate_show(struct device
*dev
,
59 struct device_attribute
*attr
, char *buf
)
61 struct zram
*zram
= dev_to_zram(dev
);
63 return sprintf(buf
, "%u\n", zram
->init_done
);
66 static ssize_t
num_reads_show(struct device
*dev
,
67 struct device_attribute
*attr
, char *buf
)
69 struct zram
*zram
= dev_to_zram(dev
);
71 return sprintf(buf
, "%llu\n",
72 (u64
)atomic64_read(&zram
->stats
.num_reads
));
75 static ssize_t
num_writes_show(struct device
*dev
,
76 struct device_attribute
*attr
, char *buf
)
78 struct zram
*zram
= dev_to_zram(dev
);
80 return sprintf(buf
, "%llu\n",
81 (u64
)atomic64_read(&zram
->stats
.num_writes
));
84 static ssize_t
invalid_io_show(struct device
*dev
,
85 struct device_attribute
*attr
, char *buf
)
87 struct zram
*zram
= dev_to_zram(dev
);
89 return sprintf(buf
, "%llu\n",
90 (u64
)atomic64_read(&zram
->stats
.invalid_io
));
93 static ssize_t
notify_free_show(struct device
*dev
,
94 struct device_attribute
*attr
, char *buf
)
96 struct zram
*zram
= dev_to_zram(dev
);
98 return sprintf(buf
, "%llu\n",
99 (u64
)atomic64_read(&zram
->stats
.notify_free
));
102 static ssize_t
zero_pages_show(struct device
*dev
,
103 struct device_attribute
*attr
, char *buf
)
105 struct zram
*zram
= dev_to_zram(dev
);
107 return sprintf(buf
, "%u\n", zram
->stats
.pages_zero
);
110 static ssize_t
orig_data_size_show(struct device
*dev
,
111 struct device_attribute
*attr
, char *buf
)
113 struct zram
*zram
= dev_to_zram(dev
);
115 return sprintf(buf
, "%llu\n",
116 (u64
)(zram
->stats
.pages_stored
) << PAGE_SHIFT
);
119 static ssize_t
compr_data_size_show(struct device
*dev
,
120 struct device_attribute
*attr
, char *buf
)
122 struct zram
*zram
= dev_to_zram(dev
);
124 return sprintf(buf
, "%llu\n",
125 (u64
)atomic64_read(&zram
->stats
.compr_size
));
128 static ssize_t
mem_used_total_show(struct device
*dev
,
129 struct device_attribute
*attr
, char *buf
)
132 struct zram
*zram
= dev_to_zram(dev
);
133 struct zram_meta
*meta
= zram
->meta
;
135 down_read(&zram
->init_lock
);
137 val
= zs_get_total_size_bytes(meta
->mem_pool
);
138 up_read(&zram
->init_lock
);
140 return sprintf(buf
, "%llu\n", val
);
143 static int zram_test_flag(struct zram_meta
*meta
, u32 index
,
144 enum zram_pageflags flag
)
146 return meta
->table
[index
].flags
& BIT(flag
);
149 static void zram_set_flag(struct zram_meta
*meta
, u32 index
,
150 enum zram_pageflags flag
)
152 meta
->table
[index
].flags
|= BIT(flag
);
155 static void zram_clear_flag(struct zram_meta
*meta
, u32 index
,
156 enum zram_pageflags flag
)
158 meta
->table
[index
].flags
&= ~BIT(flag
);
161 static inline int is_partial_io(struct bio_vec
*bvec
)
163 return bvec
->bv_len
!= PAGE_SIZE
;
167 * Check if request is within bounds and aligned on zram logical blocks.
169 static inline int valid_io_request(struct zram
*zram
, struct bio
*bio
)
171 u64 start
, end
, bound
;
173 /* unaligned request */
174 if (unlikely(bio
->bi_sector
& (ZRAM_SECTOR_PER_LOGICAL_BLOCK
- 1)))
176 if (unlikely(bio
->bi_size
& (ZRAM_LOGICAL_BLOCK_SIZE
- 1)))
179 start
= bio
->bi_sector
;
180 end
= start
+ (bio
->bi_size
>> SECTOR_SHIFT
);
181 bound
= zram
->disksize
>> SECTOR_SHIFT
;
182 /* out of range range */
183 if (unlikely(start
>= bound
|| end
> bound
|| start
> end
))
186 /* I/O request is valid */
190 static void zram_meta_free(struct zram_meta
*meta
)
192 zs_destroy_pool(meta
->mem_pool
);
193 kfree(meta
->compress_workmem
);
194 free_pages((unsigned long)meta
->compress_buffer
, 1);
199 static struct zram_meta
*zram_meta_alloc(u64 disksize
)
202 struct zram_meta
*meta
= kmalloc(sizeof(*meta
), GFP_KERNEL
);
206 meta
->compress_workmem
= kzalloc(LZO1X_MEM_COMPRESS
, GFP_KERNEL
);
207 if (!meta
->compress_workmem
)
210 meta
->compress_buffer
=
211 (void *)__get_free_pages(GFP_KERNEL
| __GFP_ZERO
, 1);
212 if (!meta
->compress_buffer
) {
213 pr_err("Error allocating compressor buffer space\n");
217 num_pages
= disksize
>> PAGE_SHIFT
;
218 meta
->table
= vzalloc(num_pages
* sizeof(*meta
->table
));
220 pr_err("Error allocating zram address table\n");
224 meta
->mem_pool
= zs_create_pool(GFP_NOIO
| __GFP_HIGHMEM
);
225 if (!meta
->mem_pool
) {
226 pr_err("Error creating memory pool\n");
235 free_pages((unsigned long)meta
->compress_buffer
, 1);
237 kfree(meta
->compress_workmem
);
245 static void update_position(u32
*index
, int *offset
, struct bio_vec
*bvec
)
247 if (*offset
+ bvec
->bv_len
>= PAGE_SIZE
)
249 *offset
= (*offset
+ bvec
->bv_len
) % PAGE_SIZE
;
252 static int page_zero_filled(void *ptr
)
257 page
= (unsigned long *)ptr
;
259 for (pos
= 0; pos
!= PAGE_SIZE
/ sizeof(*page
); pos
++) {
267 static void handle_zero_page(struct bio_vec
*bvec
)
269 struct page
*page
= bvec
->bv_page
;
272 user_mem
= kmap_atomic(page
);
273 if (is_partial_io(bvec
))
274 memset(user_mem
+ bvec
->bv_offset
, 0, bvec
->bv_len
);
276 clear_page(user_mem
);
277 kunmap_atomic(user_mem
);
279 flush_dcache_page(page
);
282 static void zram_free_page(struct zram
*zram
, size_t index
)
284 struct zram_meta
*meta
= zram
->meta
;
285 unsigned long handle
= meta
->table
[index
].handle
;
286 u16 size
= meta
->table
[index
].size
;
288 if (unlikely(!handle
)) {
290 * No memory is allocated for zero filled pages.
291 * Simply clear zero page flag.
293 if (zram_test_flag(meta
, index
, ZRAM_ZERO
)) {
294 zram_clear_flag(meta
, index
, ZRAM_ZERO
);
295 zram
->stats
.pages_zero
--;
300 if (unlikely(size
> max_zpage_size
))
301 zram
->stats
.bad_compress
--;
303 zs_free(meta
->mem_pool
, handle
);
305 if (size
<= PAGE_SIZE
/ 2)
306 zram
->stats
.good_compress
--;
308 atomic64_sub(meta
->table
[index
].size
, &zram
->stats
.compr_size
);
309 zram
->stats
.pages_stored
--;
311 meta
->table
[index
].handle
= 0;
312 meta
->table
[index
].size
= 0;
315 static int zram_decompress_page(struct zram
*zram
, char *mem
, u32 index
)
318 size_t clen
= PAGE_SIZE
;
320 struct zram_meta
*meta
= zram
->meta
;
321 unsigned long handle
= meta
->table
[index
].handle
;
323 if (!handle
|| zram_test_flag(meta
, index
, ZRAM_ZERO
)) {
328 cmem
= zs_map_object(meta
->mem_pool
, handle
, ZS_MM_RO
);
329 if (meta
->table
[index
].size
== PAGE_SIZE
)
330 copy_page(mem
, cmem
);
332 ret
= lzo1x_decompress_safe(cmem
, meta
->table
[index
].size
,
334 zs_unmap_object(meta
->mem_pool
, handle
);
336 /* Should NEVER happen. Return bio error if it does. */
337 if (unlikely(ret
!= LZO_E_OK
)) {
338 pr_err("Decompression failed! err=%d, page=%u\n", ret
, index
);
339 atomic64_inc(&zram
->stats
.failed_reads
);
346 static int zram_bvec_read(struct zram
*zram
, struct bio_vec
*bvec
,
347 u32 index
, int offset
, struct bio
*bio
)
351 unsigned char *user_mem
, *uncmem
= NULL
;
352 struct zram_meta
*meta
= zram
->meta
;
353 page
= bvec
->bv_page
;
355 if (unlikely(!meta
->table
[index
].handle
) ||
356 zram_test_flag(meta
, index
, ZRAM_ZERO
)) {
357 handle_zero_page(bvec
);
361 if (is_partial_io(bvec
))
362 /* Use a temporary buffer to decompress the page */
363 uncmem
= kmalloc(PAGE_SIZE
, GFP_NOIO
);
365 user_mem
= kmap_atomic(page
);
366 if (!is_partial_io(bvec
))
370 pr_info("Unable to allocate temp memory\n");
375 ret
= zram_decompress_page(zram
, uncmem
, index
);
376 /* Should NEVER happen. Return bio error if it does. */
377 if (unlikely(ret
!= LZO_E_OK
))
380 if (is_partial_io(bvec
))
381 memcpy(user_mem
+ bvec
->bv_offset
, uncmem
+ offset
,
384 flush_dcache_page(page
);
387 kunmap_atomic(user_mem
);
388 if (is_partial_io(bvec
))
393 static int zram_bvec_write(struct zram
*zram
, struct bio_vec
*bvec
, u32 index
,
398 unsigned long handle
;
400 unsigned char *user_mem
, *cmem
, *src
, *uncmem
= NULL
;
401 struct zram_meta
*meta
= zram
->meta
;
403 page
= bvec
->bv_page
;
404 src
= meta
->compress_buffer
;
406 if (is_partial_io(bvec
)) {
408 * This is a partial IO. We need to read the full page
409 * before to write the changes.
411 uncmem
= kmalloc(PAGE_SIZE
, GFP_NOIO
);
416 ret
= zram_decompress_page(zram
, uncmem
, index
);
422 * System overwrites unused sectors. Free memory associated
423 * with this sector now.
425 if (meta
->table
[index
].handle
||
426 zram_test_flag(meta
, index
, ZRAM_ZERO
))
427 zram_free_page(zram
, index
);
429 user_mem
= kmap_atomic(page
);
431 if (is_partial_io(bvec
)) {
432 memcpy(uncmem
+ offset
, user_mem
+ bvec
->bv_offset
,
434 kunmap_atomic(user_mem
);
440 if (page_zero_filled(uncmem
)) {
441 kunmap_atomic(user_mem
);
442 zram
->stats
.pages_zero
++;
443 zram_set_flag(meta
, index
, ZRAM_ZERO
);
448 ret
= lzo1x_1_compress(uncmem
, PAGE_SIZE
, src
, &clen
,
449 meta
->compress_workmem
);
451 if (!is_partial_io(bvec
)) {
452 kunmap_atomic(user_mem
);
457 if (unlikely(ret
!= LZO_E_OK
)) {
458 pr_err("Compression failed! err=%d\n", ret
);
462 if (unlikely(clen
> max_zpage_size
)) {
463 zram
->stats
.bad_compress
++;
466 if (is_partial_io(bvec
))
470 handle
= zs_malloc(meta
->mem_pool
, clen
);
472 pr_info("Error allocating memory for compressed page: %u, size=%zu\n",
477 cmem
= zs_map_object(meta
->mem_pool
, handle
, ZS_MM_WO
);
479 if ((clen
== PAGE_SIZE
) && !is_partial_io(bvec
)) {
480 src
= kmap_atomic(page
);
481 copy_page(cmem
, src
);
484 memcpy(cmem
, src
, clen
);
487 zs_unmap_object(meta
->mem_pool
, handle
);
489 meta
->table
[index
].handle
= handle
;
490 meta
->table
[index
].size
= clen
;
493 atomic64_add(clen
, &zram
->stats
.compr_size
);
494 zram
->stats
.pages_stored
++;
495 if (clen
<= PAGE_SIZE
/ 2)
496 zram
->stats
.good_compress
++;
499 if (is_partial_io(bvec
))
503 atomic64_inc(&zram
->stats
.failed_writes
);
507 static int zram_bvec_rw(struct zram
*zram
, struct bio_vec
*bvec
, u32 index
,
508 int offset
, struct bio
*bio
, int rw
)
513 down_read(&zram
->lock
);
514 ret
= zram_bvec_read(zram
, bvec
, index
, offset
, bio
);
515 up_read(&zram
->lock
);
517 down_write(&zram
->lock
);
518 ret
= zram_bvec_write(zram
, bvec
, index
, offset
);
519 up_write(&zram
->lock
);
525 static void zram_reset_device(struct zram
*zram
)
528 struct zram_meta
*meta
;
530 down_write(&zram
->init_lock
);
531 if (!zram
->init_done
) {
532 up_write(&zram
->init_lock
);
539 /* Free all pages that are still in this zram device */
540 for (index
= 0; index
< zram
->disksize
>> PAGE_SHIFT
; index
++) {
541 unsigned long handle
= meta
->table
[index
].handle
;
545 zs_free(meta
->mem_pool
, handle
);
548 zram_meta_free(zram
->meta
);
551 memset(&zram
->stats
, 0, sizeof(zram
->stats
));
554 set_capacity(zram
->disk
, 0);
555 up_write(&zram
->init_lock
);
558 static void zram_init_device(struct zram
*zram
, struct zram_meta
*meta
)
560 if (zram
->disksize
> 2 * (totalram_pages
<< PAGE_SHIFT
)) {
562 "There is little point creating a zram of greater than "
563 "twice the size of memory since we expect a 2:1 compression "
564 "ratio. Note that zram uses about 0.1%% of the size of "
565 "the disk when not in use so a huge zram is "
567 "\tMemory Size: %lu kB\n"
568 "\tSize you selected: %llu kB\n"
569 "Continuing anyway ...\n",
570 (totalram_pages
<< PAGE_SHIFT
) >> 10, zram
->disksize
>> 10
574 /* zram devices sort of resembles non-rotational disks */
575 queue_flag_set_unlocked(QUEUE_FLAG_NONROT
, zram
->disk
->queue
);
580 pr_debug("Initialization done!\n");
583 static ssize_t
disksize_store(struct device
*dev
,
584 struct device_attribute
*attr
, const char *buf
, size_t len
)
587 struct zram_meta
*meta
;
588 struct zram
*zram
= dev_to_zram(dev
);
590 disksize
= memparse(buf
, NULL
);
594 disksize
= PAGE_ALIGN(disksize
);
595 meta
= zram_meta_alloc(disksize
);
596 down_write(&zram
->init_lock
);
597 if (zram
->init_done
) {
598 up_write(&zram
->init_lock
);
599 zram_meta_free(meta
);
600 pr_info("Cannot change disksize for initialized device\n");
604 zram
->disksize
= disksize
;
605 set_capacity(zram
->disk
, zram
->disksize
>> SECTOR_SHIFT
);
606 zram_init_device(zram
, meta
);
607 up_write(&zram
->init_lock
);
612 static ssize_t
reset_store(struct device
*dev
,
613 struct device_attribute
*attr
, const char *buf
, size_t len
)
616 unsigned short do_reset
;
618 struct block_device
*bdev
;
620 zram
= dev_to_zram(dev
);
621 bdev
= bdget_disk(zram
->disk
, 0);
623 /* Do not reset an active device! */
624 if (bdev
->bd_holders
)
627 ret
= kstrtou16(buf
, 10, &do_reset
);
634 /* Make sure all pending I/O is finished */
638 zram_reset_device(zram
);
642 static void __zram_make_request(struct zram
*zram
, struct bio
*bio
, int rw
)
646 struct bio_vec
*bvec
;
650 atomic64_inc(&zram
->stats
.num_reads
);
653 atomic64_inc(&zram
->stats
.num_writes
);
657 index
= bio
->bi_sector
>> SECTORS_PER_PAGE_SHIFT
;
658 offset
= (bio
->bi_sector
& (SECTORS_PER_PAGE
- 1)) << SECTOR_SHIFT
;
660 bio_for_each_segment(bvec
, bio
, i
) {
661 int max_transfer_size
= PAGE_SIZE
- offset
;
663 if (bvec
->bv_len
> max_transfer_size
) {
665 * zram_bvec_rw() can only make operation on a single
666 * zram page. Split the bio vector.
670 bv
.bv_page
= bvec
->bv_page
;
671 bv
.bv_len
= max_transfer_size
;
672 bv
.bv_offset
= bvec
->bv_offset
;
674 if (zram_bvec_rw(zram
, &bv
, index
, offset
, bio
, rw
) < 0)
677 bv
.bv_len
= bvec
->bv_len
- max_transfer_size
;
678 bv
.bv_offset
+= max_transfer_size
;
679 if (zram_bvec_rw(zram
, &bv
, index
+1, 0, bio
, rw
) < 0)
682 if (zram_bvec_rw(zram
, bvec
, index
, offset
, bio
, rw
)
686 update_position(&index
, &offset
, bvec
);
689 set_bit(BIO_UPTODATE
, &bio
->bi_flags
);
698 * Handler function for all zram I/O requests.
700 static void zram_make_request(struct request_queue
*queue
, struct bio
*bio
)
702 struct zram
*zram
= queue
->queuedata
;
704 down_read(&zram
->init_lock
);
705 if (unlikely(!zram
->init_done
))
708 if (!valid_io_request(zram
, bio
)) {
709 atomic64_inc(&zram
->stats
.invalid_io
);
713 __zram_make_request(zram
, bio
, bio_data_dir(bio
));
714 up_read(&zram
->init_lock
);
719 up_read(&zram
->init_lock
);
723 static void zram_slot_free_notify(struct block_device
*bdev
,
728 zram
= bdev
->bd_disk
->private_data
;
729 down_write(&zram
->lock
);
730 zram_free_page(zram
, index
);
731 up_write(&zram
->lock
);
732 atomic64_inc(&zram
->stats
.notify_free
);
735 static const struct block_device_operations zram_devops
= {
736 .swap_slot_free_notify
= zram_slot_free_notify
,
740 static DEVICE_ATTR(disksize
, S_IRUGO
| S_IWUSR
,
741 disksize_show
, disksize_store
);
742 static DEVICE_ATTR(initstate
, S_IRUGO
, initstate_show
, NULL
);
743 static DEVICE_ATTR(reset
, S_IWUSR
, NULL
, reset_store
);
744 static DEVICE_ATTR(num_reads
, S_IRUGO
, num_reads_show
, NULL
);
745 static DEVICE_ATTR(num_writes
, S_IRUGO
, num_writes_show
, NULL
);
746 static DEVICE_ATTR(invalid_io
, S_IRUGO
, invalid_io_show
, NULL
);
747 static DEVICE_ATTR(notify_free
, S_IRUGO
, notify_free_show
, NULL
);
748 static DEVICE_ATTR(zero_pages
, S_IRUGO
, zero_pages_show
, NULL
);
749 static DEVICE_ATTR(orig_data_size
, S_IRUGO
, orig_data_size_show
, NULL
);
750 static DEVICE_ATTR(compr_data_size
, S_IRUGO
, compr_data_size_show
, NULL
);
751 static DEVICE_ATTR(mem_used_total
, S_IRUGO
, mem_used_total_show
, NULL
);
753 static struct attribute
*zram_disk_attrs
[] = {
754 &dev_attr_disksize
.attr
,
755 &dev_attr_initstate
.attr
,
756 &dev_attr_reset
.attr
,
757 &dev_attr_num_reads
.attr
,
758 &dev_attr_num_writes
.attr
,
759 &dev_attr_invalid_io
.attr
,
760 &dev_attr_notify_free
.attr
,
761 &dev_attr_zero_pages
.attr
,
762 &dev_attr_orig_data_size
.attr
,
763 &dev_attr_compr_data_size
.attr
,
764 &dev_attr_mem_used_total
.attr
,
768 static struct attribute_group zram_disk_attr_group
= {
769 .attrs
= zram_disk_attrs
,
772 static int create_device(struct zram
*zram
, int device_id
)
776 init_rwsem(&zram
->lock
);
777 init_rwsem(&zram
->init_lock
);
779 zram
->queue
= blk_alloc_queue(GFP_KERNEL
);
781 pr_err("Error allocating disk queue for device %d\n",
786 blk_queue_make_request(zram
->queue
, zram_make_request
);
787 zram
->queue
->queuedata
= zram
;
789 /* gendisk structure */
790 zram
->disk
= alloc_disk(1);
792 pr_warn("Error allocating disk structure for device %d\n",
797 zram
->disk
->major
= zram_major
;
798 zram
->disk
->first_minor
= device_id
;
799 zram
->disk
->fops
= &zram_devops
;
800 zram
->disk
->queue
= zram
->queue
;
801 zram
->disk
->private_data
= zram
;
802 snprintf(zram
->disk
->disk_name
, 16, "zram%d", device_id
);
804 /* Actual capacity set using syfs (/sys/block/zram<id>/disksize */
805 set_capacity(zram
->disk
, 0);
808 * To ensure that we always get PAGE_SIZE aligned
809 * and n*PAGE_SIZED sized I/O requests.
811 blk_queue_physical_block_size(zram
->disk
->queue
, PAGE_SIZE
);
812 blk_queue_logical_block_size(zram
->disk
->queue
,
813 ZRAM_LOGICAL_BLOCK_SIZE
);
814 blk_queue_io_min(zram
->disk
->queue
, PAGE_SIZE
);
815 blk_queue_io_opt(zram
->disk
->queue
, PAGE_SIZE
);
817 add_disk(zram
->disk
);
819 ret
= sysfs_create_group(&disk_to_dev(zram
->disk
)->kobj
,
820 &zram_disk_attr_group
);
822 pr_warn("Error creating sysfs group");
830 del_gendisk(zram
->disk
);
831 put_disk(zram
->disk
);
833 blk_cleanup_queue(zram
->queue
);
838 static void destroy_device(struct zram
*zram
)
840 sysfs_remove_group(&disk_to_dev(zram
->disk
)->kobj
,
841 &zram_disk_attr_group
);
844 del_gendisk(zram
->disk
);
845 put_disk(zram
->disk
);
849 blk_cleanup_queue(zram
->queue
);
852 static int __init
zram_init(void)
856 if (num_devices
> max_num_devices
) {
857 pr_warn("Invalid value for num_devices: %u\n",
863 zram_major
= register_blkdev(0, "zram");
864 if (zram_major
<= 0) {
865 pr_warn("Unable to get major number\n");
870 /* Allocate the device array and initialize each one */
871 zram_devices
= kzalloc(num_devices
* sizeof(struct zram
), GFP_KERNEL
);
877 for (dev_id
= 0; dev_id
< num_devices
; dev_id
++) {
878 ret
= create_device(&zram_devices
[dev_id
], dev_id
);
883 pr_info("Created %u device(s) ...\n", num_devices
);
889 destroy_device(&zram_devices
[--dev_id
]);
892 unregister_blkdev(zram_major
, "zram");
897 static void __exit
zram_exit(void)
902 for (i
= 0; i
< num_devices
; i
++) {
903 zram
= &zram_devices
[i
];
905 get_disk(zram
->disk
);
906 destroy_device(zram
);
907 zram_reset_device(zram
);
908 put_disk(zram
->disk
);
911 unregister_blkdev(zram_major
, "zram");
914 pr_debug("Cleanup done!\n");
917 module_init(zram_init
);
918 module_exit(zram_exit
);
920 module_param(num_devices
, uint
, 0);
921 MODULE_PARM_DESC(num_devices
, "Number of zram devices");
923 MODULE_LICENSE("Dual BSD/GPL");
924 MODULE_AUTHOR("Nitin Gupta <ngupta@vflare.org>");
925 MODULE_DESCRIPTION("Compressed RAM Block Device");