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/*
* Copyright (C) 2014 Sergey Senozhatsky.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/lz4.h>
#include <linux/vmalloc.h>
#include <linux/mm.h>
#include "zcomp_lz4.h"
static void *zcomp_lz4_create(void)
{
void *ret;
/*
* This function can be called in swapout/fs write path
* so we can't use GFP_FS|IO. And it assumes we already
* have at least one stream in zram initialization so we
* don't do best effort to allocate more stream in here.
* A default stream will work well without further multiple
* streams. That's why we use NORETRY | NOWARN.
*/
ret = kzalloc(LZ4_MEM_COMPRESS, GFP_NOIO | __GFP_NORETRY |
__GFP_NOWARN);
if (!ret)
ret = __vmalloc(LZ4_MEM_COMPRESS,
GFP_NOIO | __GFP_NORETRY | __GFP_NOWARN |
__GFP_ZERO | __GFP_HIGHMEM,
PAGE_KERNEL);
return ret;
}
static void zcomp_lz4_destroy(void *private)
{
kvfree(private);
}
static int zcomp_lz4_compress(const unsigned char *src, unsigned char *dst,
size_t *dst_len, void *private)
{
/* return : Success if return 0 */
return lz4_compress(src, PAGE_SIZE, dst, dst_len, private);
}
static int zcomp_lz4_decompress(const unsigned char *src, size_t src_len,
unsigned char *dst)
{
size_t dst_len = PAGE_SIZE;
/* return : Success if return 0 */
return lz4_decompress_unknownoutputsize(src, src_len, dst, &dst_len);
}
struct zcomp_backend zcomp_lz4 = {
.compress = zcomp_lz4_compress,
.decompress = zcomp_lz4_decompress,
.create = zcomp_lz4_create,
.destroy = zcomp_lz4_destroy,
.name = "lz4",
};
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