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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/string.h>
#include <linux/slab.h>
#include <linux/wait.h>
#include <linux/sched.h>
#include "zcomp.h"
#include "zcomp_lzo.h"
static struct zcomp_backend *find_backend(const char *compress)
{
if (strncmp(compress, "lzo", 3) == 0)
return &zcomp_lzo;
return NULL;
}
static void zcomp_strm_free(struct zcomp *comp, struct zcomp_strm *zstrm)
{
if (zstrm->private)
comp->backend->destroy(zstrm->private);
free_pages((unsigned long)zstrm->buffer, 1);
kfree(zstrm);
}
/*
* allocate new zcomp_strm structure with ->private initialized by
* backend, return NULL on error
*/
static struct zcomp_strm *zcomp_strm_alloc(struct zcomp *comp)
{
struct zcomp_strm *zstrm = kmalloc(sizeof(*zstrm), GFP_KERNEL);
if (!zstrm)
return NULL;
zstrm->private = comp->backend->create();
/*
* allocate 2 pages. 1 for compressed data, plus 1 extra for the
* case when compressed size is larger than the original one
*/
zstrm->buffer = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 1);
if (!zstrm->private || !zstrm->buffer) {
zcomp_strm_free(comp, zstrm);
zstrm = NULL;
}
return zstrm;
}
struct zcomp_strm *zcomp_strm_find(struct zcomp *comp)
{
mutex_lock(&comp->strm_lock);
return comp->zstrm;
}
void zcomp_strm_release(struct zcomp *comp, struct zcomp_strm *zstrm)
{
mutex_unlock(&comp->strm_lock);
}
int zcomp_compress(struct zcomp *comp, struct zcomp_strm *zstrm,
const unsigned char *src, size_t *dst_len)
{
return comp->backend->compress(src, zstrm->buffer, dst_len,
zstrm->private);
}
int zcomp_decompress(struct zcomp *comp, const unsigned char *src,
size_t src_len, unsigned char *dst)
{
return comp->backend->decompress(src, src_len, dst);
}
void zcomp_destroy(struct zcomp *comp)
{
zcomp_strm_free(comp, comp->zstrm);
kfree(comp);
}
/*
* search available compressors for requested algorithm.
* allocate new zcomp and initialize it. return NULL
* if requested algorithm is not supported or in case
* of init error
*/
struct zcomp *zcomp_create(const char *compress)
{
struct zcomp *comp;
struct zcomp_backend *backend;
backend = find_backend(compress);
if (!backend)
return NULL;
comp = kzalloc(sizeof(struct zcomp), GFP_KERNEL);
if (!comp)
return NULL;
comp->backend = backend;
mutex_init(&comp->strm_lock);
comp->zstrm = zcomp_strm_alloc(comp);
if (!comp->zstrm) {
kfree(comp);
return NULL;
}
return comp;
}
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