// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Squashfs - a compressed read only filesystem for Linux
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*
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* Copyright (c) 2016-present, Facebook, Inc.
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* All rights reserved.
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*
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* zstd_wrapper.c
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*/
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#include <linux/mutex.h>
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#include <linux/bio.h>
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#include <linux/slab.h>
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#include <linux/zstd.h>
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#include <linux/vmalloc.h>
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#include "squashfs_fs.h"
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#include "squashfs_fs_sb.h"
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#include "squashfs.h"
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#include "decompressor.h"
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#include "page_actor.h"
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struct workspace {
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void *mem;
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size_t mem_size;
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size_t window_size;
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};
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static void *zstd_init(struct squashfs_sb_info *msblk, void *buff)
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{
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struct workspace *wksp = kmalloc(sizeof(*wksp), GFP_KERNEL);
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if (wksp == NULL)
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goto failed;
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wksp->window_size = max_t(size_t,
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msblk->block_size, SQUASHFS_METADATA_SIZE);
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wksp->mem_size = ZSTD_DStreamWorkspaceBound(wksp->window_size);
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wksp->mem = vmalloc(wksp->mem_size);
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if (wksp->mem == NULL)
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goto failed;
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return wksp;
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failed:
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ERROR("Failed to allocate zstd workspace\n");
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kfree(wksp);
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return ERR_PTR(-ENOMEM);
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}
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static void zstd_free(void *strm)
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{
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struct workspace *wksp = strm;
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if (wksp)
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vfree(wksp->mem);
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kfree(wksp);
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}
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static int zstd_uncompress(struct squashfs_sb_info *msblk, void *strm,
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struct bio *bio, int offset, int length,
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struct squashfs_page_actor *output)
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{
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struct workspace *wksp = strm;
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ZSTD_DStream *stream;
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size_t total_out = 0;
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int error = 0;
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ZSTD_inBuffer in_buf = { NULL, 0, 0 };
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ZSTD_outBuffer out_buf = { NULL, 0, 0 };
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struct bvec_iter_all iter_all = {};
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struct bio_vec *bvec = bvec_init_iter_all(&iter_all);
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stream = ZSTD_initDStream(wksp->window_size, wksp->mem, wksp->mem_size);
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if (!stream) {
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ERROR("Failed to initialize zstd decompressor\n");
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return -EIO;
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}
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out_buf.size = PAGE_SIZE;
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out_buf.dst = squashfs_first_page(output);
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for (;;) {
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size_t zstd_err;
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if (in_buf.pos == in_buf.size) {
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const void *data;
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int avail;
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if (!bio_next_segment(bio, &iter_all)) {
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error = -EIO;
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break;
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}
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avail = min(length, ((int)bvec->bv_len) - offset);
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data = page_address(bvec->bv_page) + bvec->bv_offset;
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length -= avail;
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in_buf.src = data + offset;
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in_buf.size = avail;
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in_buf.pos = 0;
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offset = 0;
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}
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if (out_buf.pos == out_buf.size) {
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out_buf.dst = squashfs_next_page(output);
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if (out_buf.dst == NULL) {
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/* Shouldn't run out of pages
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* before stream is done.
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*/
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error = -EIO;
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break;
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}
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out_buf.pos = 0;
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out_buf.size = PAGE_SIZE;
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}
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total_out -= out_buf.pos;
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zstd_err = ZSTD_decompressStream(stream, &out_buf, &in_buf);
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total_out += out_buf.pos; /* add the additional data produced */
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if (zstd_err == 0)
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break;
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if (ZSTD_isError(zstd_err)) {
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ERROR("zstd decompression error: %d\n",
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(int)ZSTD_getErrorCode(zstd_err));
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error = -EIO;
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break;
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}
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}
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squashfs_finish_page(output);
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return error ? error : total_out;
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}
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const struct squashfs_decompressor squashfs_zstd_comp_ops = {
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.init = zstd_init,
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.free = zstd_free,
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.decompress = zstd_uncompress,
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.id = ZSTD_COMPRESSION,
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.name = "zstd",
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.supported = 1
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};
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