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author | Nitin Gupta <ngupta@vflare.org> | 2010-06-01 13:31:24 +0530 |
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committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-06-18 12:46:42 -0700 |
commit | 16a4bfb9e9dfefbd28ee170fa3e259bc88d81eb5 (patch) | |
tree | fc8cdc97f97b699c7ed0e0a08eacd5a3b1f3058f /drivers/staging/zram/zram_drv.c | |
parent | a1dd52afa94238d361d70502b219409ea115e235 (diff) | |
download | kernel_samsung_espresso10-16a4bfb9e9dfefbd28ee170fa3e259bc88d81eb5.zip kernel_samsung_espresso10-16a4bfb9e9dfefbd28ee170fa3e259bc88d81eb5.tar.gz kernel_samsung_espresso10-16a4bfb9e9dfefbd28ee170fa3e259bc88d81eb5.tar.bz2 |
Staging: Rename ramzswap files to zram
Related changes:
- Modify revelant Kconfig and Makefile accordingly.
- Change include filenames in code.
- Remove dependency on CONFIG_SWAP in Kconfig as zram usage
is no longer limited to swap disks.
Signed-off-by: Nitin Gupta <ngupta@vflare.org>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/staging/zram/zram_drv.c')
-rw-r--r-- | drivers/staging/zram/zram_drv.c | 805 |
1 files changed, 805 insertions, 0 deletions
diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c new file mode 100644 index 0000000..e9b064c --- /dev/null +++ b/drivers/staging/zram/zram_drv.c @@ -0,0 +1,805 @@ +/* + * Compressed RAM based swap device + * + * Copyright (C) 2008, 2009, 2010 Nitin Gupta + * + * This code is released using a dual license strategy: BSD/GPL + * You can choose the licence that better fits your requirements. + * + * Released under the terms of 3-clause BSD License + * Released under the terms of GNU General Public License Version 2.0 + * + * Project home: http://compcache.googlecode.com + */ + +#define KMSG_COMPONENT "ramzswap" +#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/bitops.h> +#include <linux/blkdev.h> +#include <linux/buffer_head.h> +#include <linux/device.h> +#include <linux/genhd.h> +#include <linux/highmem.h> +#include <linux/slab.h> +#include <linux/lzo.h> +#include <linux/string.h> +#include <linux/swap.h> +#include <linux/swapops.h> +#include <linux/vmalloc.h> + +#include "zram_drv.h" + +/* Globals */ +static int ramzswap_major; +static struct ramzswap *devices; + +/* Module params (documentation at end) */ +static unsigned int num_devices; + +static int rzs_test_flag(struct ramzswap *rzs, u32 index, + enum rzs_pageflags flag) +{ + return rzs->table[index].flags & BIT(flag); +} + +static void rzs_set_flag(struct ramzswap *rzs, u32 index, + enum rzs_pageflags flag) +{ + rzs->table[index].flags |= BIT(flag); +} + +static void rzs_clear_flag(struct ramzswap *rzs, u32 index, + enum rzs_pageflags flag) +{ + rzs->table[index].flags &= ~BIT(flag); +} + +static int page_zero_filled(void *ptr) +{ + unsigned int pos; + unsigned long *page; + + page = (unsigned long *)ptr; + + for (pos = 0; pos != PAGE_SIZE / sizeof(*page); pos++) { + if (page[pos]) + return 0; + } + + return 1; +} + +static void ramzswap_set_disksize(struct ramzswap *rzs, size_t totalram_bytes) +{ + if (!rzs->disksize) { + pr_info( + "disk size not provided. You can use disksize_kb module " + "param to specify size.\nUsing default: (%u%% of RAM).\n", + default_disksize_perc_ram + ); + rzs->disksize = default_disksize_perc_ram * + (totalram_bytes / 100); + } + + if (rzs->disksize > 2 * (totalram_bytes)) { + pr_info( + "There is little point creating a ramzswap of greater than " + "twice the size of memory since we expect a 2:1 compression " + "ratio. Note that ramzswap uses about 0.1%% of the size of " + "the swap device when not in use so a huge ramzswap is " + "wasteful.\n" + "\tMemory Size: %zu kB\n" + "\tSize you selected: %zu kB\n" + "Continuing anyway ...\n", + totalram_bytes >> 10, rzs->disksize + ); + } + + rzs->disksize &= PAGE_MASK; +} + +static void ramzswap_ioctl_get_stats(struct ramzswap *rzs, + struct ramzswap_ioctl_stats *s) +{ + s->disksize = rzs->disksize; + +#if defined(CONFIG_RAMZSWAP_STATS) + { + struct ramzswap_stats *rs = &rzs->stats; + size_t succ_writes, mem_used; + unsigned int good_compress_perc = 0, no_compress_perc = 0; + + mem_used = xv_get_total_size_bytes(rzs->mem_pool) + + (rs->pages_expand << PAGE_SHIFT); + succ_writes = rzs_stat64_read(rzs, &rs->num_writes) - + rzs_stat64_read(rzs, &rs->failed_writes); + + if (succ_writes && rs->pages_stored) { + good_compress_perc = rs->good_compress * 100 + / rs->pages_stored; + no_compress_perc = rs->pages_expand * 100 + / rs->pages_stored; + } + + s->num_reads = rzs_stat64_read(rzs, &rs->num_reads); + s->num_writes = rzs_stat64_read(rzs, &rs->num_writes); + s->failed_reads = rzs_stat64_read(rzs, &rs->failed_reads); + s->failed_writes = rzs_stat64_read(rzs, &rs->failed_writes); + s->invalid_io = rzs_stat64_read(rzs, &rs->invalid_io); + s->notify_free = rzs_stat64_read(rzs, &rs->notify_free); + s->pages_zero = rs->pages_zero; + + s->good_compress_pct = good_compress_perc; + s->pages_expand_pct = no_compress_perc; + + s->pages_stored = rs->pages_stored; + s->pages_used = mem_used >> PAGE_SHIFT; + s->orig_data_size = rs->pages_stored << PAGE_SHIFT; + s->compr_data_size = rs->compr_size; + s->mem_used_total = mem_used; + } +#endif /* CONFIG_RAMZSWAP_STATS */ +} + +static void ramzswap_free_page(struct ramzswap *rzs, size_t index) +{ + u32 clen; + void *obj; + + struct page *page = rzs->table[index].page; + u32 offset = rzs->table[index].offset; + + if (unlikely(!page)) { + /* + * No memory is allocated for zero filled pages. + * Simply clear zero page flag. + */ + if (rzs_test_flag(rzs, index, RZS_ZERO)) { + rzs_clear_flag(rzs, index, RZS_ZERO); + rzs_stat_dec(&rzs->stats.pages_zero); + } + return; + } + + if (unlikely(rzs_test_flag(rzs, index, RZS_UNCOMPRESSED))) { + clen = PAGE_SIZE; + __free_page(page); + rzs_clear_flag(rzs, index, RZS_UNCOMPRESSED); + rzs_stat_dec(&rzs->stats.pages_expand); + goto out; + } + + obj = kmap_atomic(page, KM_USER0) + offset; + clen = xv_get_object_size(obj) - sizeof(struct zobj_header); + kunmap_atomic(obj, KM_USER0); + + xv_free(rzs->mem_pool, page, offset); + if (clen <= PAGE_SIZE / 2) + rzs_stat_dec(&rzs->stats.good_compress); + +out: + rzs->stats.compr_size -= clen; + rzs_stat_dec(&rzs->stats.pages_stored); + + rzs->table[index].page = NULL; + rzs->table[index].offset = 0; +} + +static void handle_zero_page(struct page *page) +{ + void *user_mem; + + user_mem = kmap_atomic(page, KM_USER0); + memset(user_mem, 0, PAGE_SIZE); + kunmap_atomic(user_mem, KM_USER0); + + flush_dcache_page(page); +} + +static void handle_uncompressed_page(struct ramzswap *rzs, + struct page *page, u32 index) +{ + unsigned char *user_mem, *cmem; + + user_mem = kmap_atomic(page, KM_USER0); + cmem = kmap_atomic(rzs->table[index].page, KM_USER1) + + rzs->table[index].offset; + + memcpy(user_mem, cmem, PAGE_SIZE); + kunmap_atomic(user_mem, KM_USER0); + kunmap_atomic(cmem, KM_USER1); + + flush_dcache_page(page); +} + +static int ramzswap_read(struct ramzswap *rzs, struct bio *bio) +{ + + int i; + u32 index; + struct bio_vec *bvec; + + rzs_stat64_inc(rzs, &rzs->stats.num_reads); + + index = bio->bi_sector >> SECTORS_PER_PAGE_SHIFT; + bio_for_each_segment(bvec, bio, i) { + int ret; + size_t clen; + struct page *page; + struct zobj_header *zheader; + unsigned char *user_mem, *cmem; + + page = bvec->bv_page; + + if (rzs_test_flag(rzs, index, RZS_ZERO)) { + handle_zero_page(page); + continue; + } + + /* Requested page is not present in compressed area */ + if (unlikely(!rzs->table[index].page)) { + pr_debug("Read before write: sector=%lu, size=%u", + (ulong)(bio->bi_sector), bio->bi_size); + /* Do nothing */ + continue; + } + + /* Page is stored uncompressed since it's incompressible */ + if (unlikely(rzs_test_flag(rzs, index, RZS_UNCOMPRESSED))) { + handle_uncompressed_page(rzs, page, index); + continue; + } + + user_mem = kmap_atomic(page, KM_USER0); + clen = PAGE_SIZE; + + cmem = kmap_atomic(rzs->table[index].page, KM_USER1) + + rzs->table[index].offset; + + ret = lzo1x_decompress_safe( + cmem + sizeof(*zheader), + xv_get_object_size(cmem) - sizeof(*zheader), + user_mem, &clen); + + kunmap_atomic(user_mem, KM_USER0); + kunmap_atomic(cmem, KM_USER1); + + /* Should NEVER happen. Return bio error if it does. */ + if (unlikely(ret != LZO_E_OK)) { + pr_err("Decompression failed! err=%d, page=%u\n", + ret, index); + rzs_stat64_inc(rzs, &rzs->stats.failed_reads); + goto out; + } + + flush_dcache_page(page); + index++; + } + + set_bit(BIO_UPTODATE, &bio->bi_flags); + bio_endio(bio, 0); + return 0; + +out: + bio_io_error(bio); + return 0; +} + +static int ramzswap_write(struct ramzswap *rzs, struct bio *bio) +{ + int i; + u32 index; + struct bio_vec *bvec; + + rzs_stat64_inc(rzs, &rzs->stats.num_writes); + + index = bio->bi_sector >> SECTORS_PER_PAGE_SHIFT; + + bio_for_each_segment(bvec, bio, i) { + int ret; + u32 offset; + size_t clen; + struct zobj_header *zheader; + struct page *page, *page_store; + unsigned char *user_mem, *cmem, *src; + + page = bvec->bv_page; + src = rzs->compress_buffer; + + /* + * System overwrites unused sectors. Free memory associated + * with this sector now. + */ + if (rzs->table[index].page || + rzs_test_flag(rzs, index, RZS_ZERO)) + ramzswap_free_page(rzs, index); + + mutex_lock(&rzs->lock); + + user_mem = kmap_atomic(page, KM_USER0); + if (page_zero_filled(user_mem)) { + kunmap_atomic(user_mem, KM_USER0); + mutex_unlock(&rzs->lock); + rzs_stat_inc(&rzs->stats.pages_zero); + rzs_set_flag(rzs, index, RZS_ZERO); + continue; + } + + ret = lzo1x_1_compress(user_mem, PAGE_SIZE, src, &clen, + rzs->compress_workmem); + + kunmap_atomic(user_mem, KM_USER0); + + if (unlikely(ret != LZO_E_OK)) { + mutex_unlock(&rzs->lock); + pr_err("Compression failed! err=%d\n", ret); + rzs_stat64_inc(rzs, &rzs->stats.failed_writes); + goto out; + } + + /* + * Page is incompressible. Store it as-is (uncompressed) + * since we do not want to return too many swap write + * errors which has side effect of hanging the system. + */ + if (unlikely(clen > max_zpage_size)) { + clen = PAGE_SIZE; + page_store = alloc_page(GFP_NOIO | __GFP_HIGHMEM); + if (unlikely(!page_store)) { + mutex_unlock(&rzs->lock); + pr_info("Error allocating memory for " + "incompressible page: %u\n", index); + rzs_stat64_inc(rzs, &rzs->stats.failed_writes); + goto out; + } + + offset = 0; + rzs_set_flag(rzs, index, RZS_UNCOMPRESSED); + rzs_stat_inc(&rzs->stats.pages_expand); + rzs->table[index].page = page_store; + src = kmap_atomic(page, KM_USER0); + goto memstore; + } + + if (xv_malloc(rzs->mem_pool, clen + sizeof(*zheader), + &rzs->table[index].page, &offset, + GFP_NOIO | __GFP_HIGHMEM)) { + mutex_unlock(&rzs->lock); + pr_info("Error allocating memory for compressed " + "page: %u, size=%zu\n", index, clen); + rzs_stat64_inc(rzs, &rzs->stats.failed_writes); + goto out; + } + +memstore: + rzs->table[index].offset = offset; + + cmem = kmap_atomic(rzs->table[index].page, KM_USER1) + + rzs->table[index].offset; + +#if 0 + /* Back-reference needed for memory defragmentation */ + if (!rzs_test_flag(rzs, index, RZS_UNCOMPRESSED)) { + zheader = (struct zobj_header *)cmem; + zheader->table_idx = index; + cmem += sizeof(*zheader); + } +#endif + + memcpy(cmem, src, clen); + + kunmap_atomic(cmem, KM_USER1); + if (unlikely(rzs_test_flag(rzs, index, RZS_UNCOMPRESSED))) + kunmap_atomic(src, KM_USER0); + + /* Update stats */ + rzs->stats.compr_size += clen; + rzs_stat_inc(&rzs->stats.pages_stored); + if (clen <= PAGE_SIZE / 2) + rzs_stat_inc(&rzs->stats.good_compress); + + mutex_unlock(&rzs->lock); + index++; + } + + set_bit(BIO_UPTODATE, &bio->bi_flags); + bio_endio(bio, 0); + return 0; + +out: + bio_io_error(bio); + return 0; +} + +/* + * Check if request is within bounds and page aligned. + */ +static inline int valid_io_request(struct ramzswap *rzs, struct bio *bio) +{ + if (unlikely( + (bio->bi_sector >= (rzs->disksize >> SECTOR_SHIFT)) || + (bio->bi_sector & (SECTORS_PER_PAGE - 1)) || + (bio->bi_size & (PAGE_SIZE - 1)))) { + + return 0; + } + + /* I/O request is valid */ + return 1; +} + +/* + * Handler function for all ramzswap I/O requests. + */ +static int ramzswap_make_request(struct request_queue *queue, struct bio *bio) +{ + int ret = 0; + struct ramzswap *rzs = queue->queuedata; + + if (unlikely(!rzs->init_done)) { + bio_io_error(bio); + return 0; + } + + if (!valid_io_request(rzs, bio)) { + rzs_stat64_inc(rzs, &rzs->stats.invalid_io); + bio_io_error(bio); + return 0; + } + + switch (bio_data_dir(bio)) { + case READ: + ret = ramzswap_read(rzs, bio); + break; + + case WRITE: + ret = ramzswap_write(rzs, bio); + break; + } + + return ret; +} + +static void reset_device(struct ramzswap *rzs) +{ + size_t index; + + /* Do not accept any new I/O request */ + rzs->init_done = 0; + + /* Free various per-device buffers */ + kfree(rzs->compress_workmem); + free_pages((unsigned long)rzs->compress_buffer, 1); + + rzs->compress_workmem = NULL; + rzs->compress_buffer = NULL; + + /* Free all pages that are still in this ramzswap device */ + for (index = 0; index < rzs->disksize >> PAGE_SHIFT; index++) { + struct page *page; + u16 offset; + + page = rzs->table[index].page; + offset = rzs->table[index].offset; + + if (!page) + continue; + + if (unlikely(rzs_test_flag(rzs, index, RZS_UNCOMPRESSED))) + __free_page(page); + else + xv_free(rzs->mem_pool, page, offset); + } + + vfree(rzs->table); + rzs->table = NULL; + + xv_destroy_pool(rzs->mem_pool); + rzs->mem_pool = NULL; + + /* Reset stats */ + memset(&rzs->stats, 0, sizeof(rzs->stats)); + + rzs->disksize = 0; +} + +static int ramzswap_ioctl_init_device(struct ramzswap *rzs) +{ + int ret; + size_t num_pages; + + if (rzs->init_done) { + pr_info("Device already initialized!\n"); + return -EBUSY; + } + + ramzswap_set_disksize(rzs, totalram_pages << PAGE_SHIFT); + + rzs->compress_workmem = kzalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL); + if (!rzs->compress_workmem) { + pr_err("Error allocating compressor working memory!\n"); + ret = -ENOMEM; + goto fail; + } + + rzs->compress_buffer = (void *)__get_free_pages(__GFP_ZERO, 1); + if (!rzs->compress_buffer) { + pr_err("Error allocating compressor buffer space\n"); + ret = -ENOMEM; + goto fail; + } + + num_pages = rzs->disksize >> PAGE_SHIFT; + rzs->table = vmalloc(num_pages * sizeof(*rzs->table)); + if (!rzs->table) { + pr_err("Error allocating ramzswap address table\n"); + /* To prevent accessing table entries during cleanup */ + rzs->disksize = 0; + ret = -ENOMEM; + goto fail; + } + memset(rzs->table, 0, num_pages * sizeof(*rzs->table)); + + set_capacity(rzs->disk, rzs->disksize >> SECTOR_SHIFT); + + /* ramzswap devices sort of resembles non-rotational disks */ + queue_flag_set_unlocked(QUEUE_FLAG_NONROT, rzs->disk->queue); + + rzs->mem_pool = xv_create_pool(); + if (!rzs->mem_pool) { + pr_err("Error creating memory pool\n"); + ret = -ENOMEM; + goto fail; + } + + rzs->init_done = 1; + + pr_debug("Initialization done!\n"); + return 0; + +fail: + reset_device(rzs); + + pr_err("Initialization failed: err=%d\n", ret); + return ret; +} + +static int ramzswap_ioctl_reset_device(struct ramzswap *rzs) +{ + if (rzs->init_done) + reset_device(rzs); + + return 0; +} + +static int ramzswap_ioctl(struct block_device *bdev, fmode_t mode, + unsigned int cmd, unsigned long arg) +{ + int ret = 0; + size_t disksize_kb; + + struct ramzswap *rzs = bdev->bd_disk->private_data; + + switch (cmd) { + case RZSIO_SET_DISKSIZE_KB: + if (rzs->init_done) { + ret = -EBUSY; + goto out; + } + if (copy_from_user(&disksize_kb, (void *)arg, + _IOC_SIZE(cmd))) { + ret = -EFAULT; + goto out; + } + rzs->disksize = disksize_kb << 10; + pr_info("Disk size set to %zu kB\n", disksize_kb); + break; + + case RZSIO_GET_STATS: + { + struct ramzswap_ioctl_stats *stats; + if (!rzs->init_done) { + ret = -ENOTTY; + goto out; + } + stats = kzalloc(sizeof(*stats), GFP_KERNEL); + if (!stats) { + ret = -ENOMEM; + goto out; + } + ramzswap_ioctl_get_stats(rzs, stats); + if (copy_to_user((void *)arg, stats, sizeof(*stats))) { + kfree(stats); + ret = -EFAULT; + goto out; + } + kfree(stats); + break; + } + case RZSIO_INIT: + ret = ramzswap_ioctl_init_device(rzs); + break; + + case RZSIO_RESET: + /* Do not reset an active device! */ + if (bdev->bd_holders) { + ret = -EBUSY; + goto out; + } + + /* Make sure all pending I/O is finished */ + if (bdev) + fsync_bdev(bdev); + + ret = ramzswap_ioctl_reset_device(rzs); + break; + + default: + pr_info("Invalid ioctl %u\n", cmd); + ret = -ENOTTY; + } + +out: + return ret; +} + +void ramzswap_slot_free_notify(struct block_device *bdev, unsigned long index) +{ + struct ramzswap *rzs; + + rzs = bdev->bd_disk->private_data; + ramzswap_free_page(rzs, index); + rzs_stat64_inc(rzs, &rzs->stats.notify_free); +} + +static const struct block_device_operations ramzswap_devops = { + .ioctl = ramzswap_ioctl, + .swap_slot_free_notify = ramzswap_slot_free_notify, + .owner = THIS_MODULE +}; + +static int create_device(struct ramzswap *rzs, int device_id) +{ + int ret = 0; + + mutex_init(&rzs->lock); + spin_lock_init(&rzs->stat64_lock); + + rzs->queue = blk_alloc_queue(GFP_KERNEL); + if (!rzs->queue) { + pr_err("Error allocating disk queue for device %d\n", + device_id); + ret = -ENOMEM; + goto out; + } + + blk_queue_make_request(rzs->queue, ramzswap_make_request); + rzs->queue->queuedata = rzs; + + /* gendisk structure */ + rzs->disk = alloc_disk(1); + if (!rzs->disk) { + blk_cleanup_queue(rzs->queue); + pr_warning("Error allocating disk structure for device %d\n", + device_id); + ret = -ENOMEM; + goto out; + } + + rzs->disk->major = ramzswap_major; + rzs->disk->first_minor = device_id; + rzs->disk->fops = &ramzswap_devops; + rzs->disk->queue = rzs->queue; + rzs->disk->private_data = rzs; + snprintf(rzs->disk->disk_name, 16, "ramzswap%d", device_id); + + /* Actual capacity set using RZSIO_SET_DISKSIZE_KB ioctl */ + set_capacity(rzs->disk, 0); + + /* + * To ensure that we always get PAGE_SIZE aligned + * and n*PAGE_SIZED sized I/O requests. + */ + blk_queue_physical_block_size(rzs->disk->queue, PAGE_SIZE); + blk_queue_logical_block_size(rzs->disk->queue, PAGE_SIZE); + blk_queue_io_min(rzs->disk->queue, PAGE_SIZE); + blk_queue_io_opt(rzs->disk->queue, PAGE_SIZE); + + add_disk(rzs->disk); + + rzs->init_done = 0; + +out: + return ret; +} + +static void destroy_device(struct ramzswap *rzs) +{ + if (rzs->disk) { + del_gendisk(rzs->disk); + put_disk(rzs->disk); + } + + if (rzs->queue) + blk_cleanup_queue(rzs->queue); +} + +static int __init ramzswap_init(void) +{ + int ret, dev_id; + + if (num_devices > max_num_devices) { + pr_warning("Invalid value for num_devices: %u\n", + num_devices); + ret = -EINVAL; + goto out; + } + + ramzswap_major = register_blkdev(0, "ramzswap"); + if (ramzswap_major <= 0) { + pr_warning("Unable to get major number\n"); + ret = -EBUSY; + goto out; + } + + if (!num_devices) { + pr_info("num_devices not specified. Using default: 1\n"); + num_devices = 1; + } + + /* Allocate the device array and initialize each one */ + pr_info("Creating %u devices ...\n", num_devices); + devices = kzalloc(num_devices * sizeof(struct ramzswap), GFP_KERNEL); + if (!devices) { + ret = -ENOMEM; + goto unregister; + } + + for (dev_id = 0; dev_id < num_devices; dev_id++) { + ret = create_device(&devices[dev_id], dev_id); + if (ret) + goto free_devices; + } + + return 0; + +free_devices: + while (dev_id) + destroy_device(&devices[--dev_id]); +unregister: + unregister_blkdev(ramzswap_major, "ramzswap"); +out: + return ret; +} + +static void __exit ramzswap_exit(void) +{ + int i; + struct ramzswap *rzs; + + for (i = 0; i < num_devices; i++) { + rzs = &devices[i]; + + destroy_device(rzs); + if (rzs->init_done) + reset_device(rzs); + } + + unregister_blkdev(ramzswap_major, "ramzswap"); + + kfree(devices); + pr_debug("Cleanup done!\n"); +} + +module_param(num_devices, uint, 0); +MODULE_PARM_DESC(num_devices, "Number of ramzswap devices"); + +module_init(ramzswap_init); +module_exit(ramzswap_exit); + +MODULE_LICENSE("Dual BSD/GPL"); +MODULE_AUTHOR("Nitin Gupta <ngupta@vflare.org>"); +MODULE_DESCRIPTION("Compressed RAM Based Swap Device"); |