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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2013
* Phillip Lougher <phillip@squashfs.org.uk>
*/
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/percpu.h>
#include <linux/buffer_head.h>
#include <linux/local_lock.h>
#include "squashfs_fs.h"
#include "squashfs_fs_sb.h"
#include "decompressor.h"
#include "squashfs.h"
/*
* This file implements multi-threaded decompression using percpu
* variables, one thread per cpu core.
*/
struct squashfs_stream {
void *stream;
local_lock_t lock;
};
static void *squashfs_decompressor_create(struct squashfs_sb_info *msblk,
void *comp_opts)
{
struct squashfs_stream *stream;
struct squashfs_stream __percpu *percpu;
int err, cpu;
percpu = alloc_percpu(struct squashfs_stream);
if (percpu == NULL)
return ERR_PTR(-ENOMEM);
for_each_possible_cpu(cpu) {
stream = per_cpu_ptr(percpu, cpu);
stream->stream = msblk->decompressor->init(msblk, comp_opts);
if (IS_ERR(stream->stream)) {
err = PTR_ERR(stream->stream);
goto out;
}
local_lock_init(&stream->lock);
}
kfree(comp_opts);
return (__force void *) percpu;
out:
for_each_possible_cpu(cpu) {
stream = per_cpu_ptr(percpu, cpu);
if (!IS_ERR_OR_NULL(stream->stream))
msblk->decompressor->free(stream->stream);
}
free_percpu(percpu);
return ERR_PTR(err);
}
static void squashfs_decompressor_destroy(struct squashfs_sb_info *msblk)
{
struct squashfs_stream __percpu *percpu =
(struct squashfs_stream __percpu *) msblk->stream;
struct squashfs_stream *stream;
int cpu;
if (msblk->stream) {
for_each_possible_cpu(cpu) {
stream = per_cpu_ptr(percpu, cpu);
msblk->decompressor->free(stream->stream);
}
free_percpu(percpu);
}
}
static int squashfs_decompress(struct squashfs_sb_info *msblk, struct bio *bio,
int offset, int length, struct squashfs_page_actor *output)
{
struct squashfs_stream *stream;
struct squashfs_stream __percpu *percpu =
(struct squashfs_stream __percpu *) msblk->stream;
int res;
local_lock(&percpu->lock);
stream = this_cpu_ptr(percpu);
res = msblk->decompressor->decompress(msblk, stream->stream, bio,
offset, length, output);
local_unlock(&percpu->lock);
if (res < 0)
ERROR("%s decompression failed, data probably corrupt\n",
msblk->decompressor->name);
return res;
}
static int squashfs_max_decompressors(void)
{
return num_possible_cpus();
}
const struct squashfs_decompressor_thread_ops squashfs_decompressor_percpu = {
.create = squashfs_decompressor_create,
.destroy = squashfs_decompressor_destroy,
.decompress = squashfs_decompress,
.max_decompressors = squashfs_max_decompressors,
};
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