// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2013
 * Phillip Lougher <phillip@squashfs.org.uk>
 */

#include <linux/types.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/bio.h>

#include "squashfs_fs.h"
#include "squashfs_fs_sb.h"
#include "decompressor.h"
#include "squashfs.h"

/*
 * This file implements single-threaded decompression in the
 * decompressor framework
 */

struct squashfs_stream {
        void            *stream;
        struct mutex    mutex;
};

static void *squashfs_decompressor_create(struct squashfs_sb_info *msblk,
                                                void *comp_opts)
{
        struct squashfs_stream *stream;
        int err = -ENOMEM;

        stream = kmalloc_obj(*stream);
        if (stream == NULL)
                goto out;

        stream->stream = msblk->decompressor->init(msblk, comp_opts);
        if (IS_ERR(stream->stream)) {
                err = PTR_ERR(stream->stream);
                goto out;
        }

        kfree(comp_opts);
        mutex_init(&stream->mutex);
        return stream;

out:
        kfree(stream);
        return ERR_PTR(err);
}

static void squashfs_decompressor_destroy(struct squashfs_sb_info *msblk)
{
        struct squashfs_stream *stream = msblk->stream;

        if (stream) {
                msblk->decompressor->free(stream->stream);
                kfree(stream);
        }
}

static int squashfs_decompress(struct squashfs_sb_info *msblk, struct bio *bio,
                        int offset, int length,
                        struct squashfs_page_actor *output)
{
        int res;
        struct squashfs_stream *stream = msblk->stream;

        mutex_lock(&stream->mutex);
        res = msblk->decompressor->decompress(msblk, stream->stream, bio,
                offset, length, output);
        mutex_unlock(&stream->mutex);

        if (res < 0)
                ERROR("%s decompression failed, data probably corrupt\n",
                        msblk->decompressor->name);

        return res;
}

static int squashfs_max_decompressors(void)
{
        return 1;
}

const struct squashfs_decompressor_thread_ops squashfs_decompressor_single = {
        .create = squashfs_decompressor_create,
        .destroy = squashfs_decompressor_destroy,
        .decompress = squashfs_decompress,
        .max_decompressors = squashfs_max_decompressors,
};