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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/err.h>
#include <linux/slab.h>
#include <linux/wait.h>
#include <linux/sched.h>
#include <linux/cpu.h>
#include "zcomp.h"
#include "zcomp_lzo.h"
#ifdef CONFIG_ZRAM_LZ4_COMPRESS
#include "zcomp_lz4.h"
#endif
static struct zcomp_backend *backends[] = {
&zcomp_lzo,
#ifdef CONFIG_ZRAM_LZ4_COMPRESS
&zcomp_lz4,
#endif
NULL
};
static struct zcomp_backend *find_backend(const char *compress)
{
int i = 0;
while (backends[i]) {
if (sysfs_streq(compress, backends[i]->name))
break;
i++;
}
return backends[i];
}
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, gfp_t flags)
{
struct zcomp_strm *zstrm = kmalloc(sizeof(*zstrm), flags);
if (!zstrm)
return NULL;
zstrm->private = comp->backend->create(flags);
/*
* 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(flags | __GFP_ZERO, 1);
if (!zstrm->private || !zstrm->buffer) {
zcomp_strm_free(comp, zstrm);
zstrm = NULL;
}
return zstrm;
}
/* show available compressors */
ssize_t zcomp_available_show(const char *comp, char *buf)
{
ssize_t sz = 0;
int i = 0;
while (backends[i]) {
if (!strcmp(comp, backends[i]->name))
sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2,
"[%s] ", backends[i]->name);
else
sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2,
"%s ", backends[i]->name);
i++;
}
sz += scnprintf(buf + sz, PAGE_SIZE - sz, "\n");
return sz;
}
bool zcomp_available_algorithm(const char *comp)
{
return find_backend(comp) != NULL;
}
struct zcomp_strm *zcomp_strm_find(struct zcomp *comp)
{
return *get_cpu_ptr(comp->stream);
}
void zcomp_strm_release(struct zcomp *comp, struct zcomp_strm *zstrm)
{
put_cpu_ptr(comp->stream);
}
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);
}
static int __zcomp_cpu_notifier(struct zcomp *comp,
unsigned long action, unsigned long cpu)
{
struct zcomp_strm *zstrm;
switch (action) {
case CPU_UP_PREPARE:
if (WARN_ON(*per_cpu_ptr(comp->stream, cpu)))
break;
zstrm = zcomp_strm_alloc(comp, GFP_KERNEL);
if (IS_ERR_OR_NULL(zstrm)) {
pr_err("Can't allocate a compression stream\n");
return NOTIFY_BAD;
}
*per_cpu_ptr(comp->stream, cpu) = zstrm;
break;
case CPU_DEAD:
case CPU_UP_CANCELED:
zstrm = *per_cpu_ptr(comp->stream, cpu);
if (!IS_ERR_OR_NULL(zstrm))
zcomp_strm_free(comp, zstrm);
*per_cpu_ptr(comp->stream, cpu) = NULL;
break;
default:
break;
}
return NOTIFY_OK;
}
static int zcomp_cpu_notifier(struct notifier_block *nb,
unsigned long action, void *pcpu)
{
unsigned long cpu = (unsigned long)pcpu;
struct zcomp *comp = container_of(nb, typeof(*comp), notifier);
return __zcomp_cpu_notifier(comp, action, cpu);
}
static int zcomp_init(struct zcomp *comp)
{
unsigned long cpu;
int ret;
comp->notifier.notifier_call = zcomp_cpu_notifier;
comp->stream = alloc_percpu(struct zcomp_strm *);
if (!comp->stream)
return -ENOMEM;
cpu_notifier_register_begin();
for_each_online_cpu(cpu) {
ret = __zcomp_cpu_notifier(comp, CPU_UP_PREPARE, cpu);
if (ret == NOTIFY_BAD)
goto cleanup;
}
__register_cpu_notifier(&comp->notifier);
cpu_notifier_register_done();
return 0;
cleanup:
for_each_online_cpu(cpu)
__zcomp_cpu_notifier(comp, CPU_UP_CANCELED, cpu);
cpu_notifier_register_done();
return -ENOMEM;
}
void zcomp_destroy(struct zcomp *comp)
{
unsigned long cpu;
cpu_notifier_register_begin();
for_each_online_cpu(cpu)
__zcomp_cpu_notifier(comp, CPU_UP_CANCELED, cpu);
__unregister_cpu_notifier(&comp->notifier);
cpu_notifier_register_done();
free_percpu(comp->stream);
kfree(comp);
}
/*
* search available compressors for requested algorithm.
* allocate new zcomp and initialize it. return compressing
* backend pointer or ERR_PTR if things went bad. ERR_PTR(-EINVAL)
* if requested algorithm is not supported, ERR_PTR(-ENOMEM) in
* case of allocation error, or any other error potentially
* returned by zcomp_init().
*/
struct zcomp *zcomp_create(const char *compress)
{
struct zcomp *comp;
struct zcomp_backend *backend;
int error;
backend = find_backend(compress);
if (!backend)
return ERR_PTR(-EINVAL);
comp = kzalloc(sizeof(struct zcomp), GFP_KERNEL);
if (!comp)
return ERR_PTR(-ENOMEM);
comp->backend = backend;
error = zcomp_init(comp);
if (error) {
kfree(comp);
return ERR_PTR(error);
}
return comp;
}
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