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/*
* Squashfs - a compressed read only filesystem for Linux
*
* Copyright (c) 2016-present, Facebook, Inc.
* All rights reserved.
*
* 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,
* or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* zstd_wrapper.c
*/
#include <linux/mutex.h>
#include <linux/buffer_head.h>
#include <linux/slab.h>
#include <linux/zstd.h>
#include <linux/vmalloc.h>
#include "squashfs_fs.h"
#include "squashfs_fs_sb.h"
#include "squashfs.h"
#include "decompressor.h"
#include "page_actor.h"
struct workspace {
void *mem;
size_t mem_size;
size_t window_size;
};
static void *zstd_init(struct squashfs_sb_info *msblk, void *buff)
{
struct workspace *wksp = kmalloc(sizeof(*wksp), GFP_KERNEL);
if (wksp == NULL)
goto failed;
wksp->window_size = max_t(size_t,
msblk->block_size, SQUASHFS_METADATA_SIZE);
wksp->mem_size = ZSTD_DStreamWorkspaceBound(wksp->window_size);
wksp->mem = vmalloc(wksp->mem_size);
if (wksp->mem == NULL)
goto failed;
return wksp;
failed:
ERROR("Failed to allocate zstd workspace\n");
kfree(wksp);
return ERR_PTR(-ENOMEM);
}
static void zstd_free(void *strm)
{
struct workspace *wksp = strm;
if (wksp)
vfree(wksp->mem);
kfree(wksp);
}
static int zstd_uncompress(struct squashfs_sb_info *msblk, void *strm,
struct buffer_head **bh, int b, int offset, int length,
struct squashfs_page_actor *output)
{
struct workspace *wksp = strm;
ZSTD_DStream *stream;
size_t total_out = 0;
size_t zstd_err;
int k = 0;
ZSTD_inBuffer in_buf = { NULL, 0, 0 };
ZSTD_outBuffer out_buf = { NULL, 0, 0 };
stream = ZSTD_initDStream(wksp->window_size, wksp->mem, wksp->mem_size);
if (!stream) {
ERROR("Failed to initialize zstd decompressor\n");
goto out;
}
out_buf.size = PAGE_SIZE;
out_buf.dst = squashfs_first_page(output);
do {
if (in_buf.pos == in_buf.size && k < b) {
int avail = min(length, msblk->devblksize - offset);
length -= avail;
in_buf.src = bh[k]->b_data + offset;
in_buf.size = avail;
in_buf.pos = 0;
offset = 0;
}
if (out_buf.pos == out_buf.size) {
out_buf.dst = squashfs_next_page(output);
if (out_buf.dst == NULL) {
/* Shouldn't run out of pages
* before stream is done.
*/
squashfs_finish_page(output);
goto out;
}
out_buf.pos = 0;
out_buf.size = PAGE_SIZE;
}
total_out -= out_buf.pos;
zstd_err = ZSTD_decompressStream(stream, &out_buf, &in_buf);
total_out += out_buf.pos; /* add the additional data produced */
if (in_buf.pos == in_buf.size && k < b)
put_bh(bh[k++]);
} while (zstd_err != 0 && !ZSTD_isError(zstd_err));
squashfs_finish_page(output);
if (ZSTD_isError(zstd_err)) {
ERROR("zstd decompression error: %d\n",
(int)ZSTD_getErrorCode(zstd_err));
goto out;
}
if (k < b)
goto out;
return (int)total_out;
out:
for (; k < b; k++)
put_bh(bh[k]);
return -EIO;
}
const struct squashfs_decompressor squashfs_zstd_comp_ops = {
.init = zstd_init,
.free = zstd_free,
.decompress = zstd_uncompress,
.id = ZSTD_COMPRESSION,
.name = "zstd",
.supported = 1
};
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