155 lines · c
1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Squashfs - a compressed read only filesystem for Linux4 *5 * Copyright (c) 2016-present, Facebook, Inc.6 * All rights reserved.7 *8 * zstd_wrapper.c9 */10 11#include <linux/mutex.h>12#include <linux/bio.h>13#include <linux/slab.h>14#include <linux/zstd.h>15#include <linux/vmalloc.h>16 17#include "squashfs_fs.h"18#include "squashfs_fs_sb.h"19#include "squashfs.h"20#include "decompressor.h"21#include "page_actor.h"22 23struct workspace {24 void *mem;25 size_t mem_size;26 size_t window_size;27};28 29static void *zstd_init(struct squashfs_sb_info *msblk, void *buff)30{31 struct workspace *wksp = kmalloc(sizeof(*wksp), GFP_KERNEL);32 33 if (wksp == NULL)34 goto failed;35 wksp->window_size = max_t(size_t,36 msblk->block_size, SQUASHFS_METADATA_SIZE);37 wksp->mem_size = zstd_dstream_workspace_bound(wksp->window_size);38 wksp->mem = vmalloc(wksp->mem_size);39 if (wksp->mem == NULL)40 goto failed;41 42 return wksp;43 44failed:45 ERROR("Failed to allocate zstd workspace\n");46 kfree(wksp);47 return ERR_PTR(-ENOMEM);48}49 50 51static void zstd_free(void *strm)52{53 struct workspace *wksp = strm;54 55 if (wksp)56 vfree(wksp->mem);57 kfree(wksp);58}59 60 61static int zstd_uncompress(struct squashfs_sb_info *msblk, void *strm,62 struct bio *bio, int offset, int length,63 struct squashfs_page_actor *output)64{65 struct workspace *wksp = strm;66 zstd_dstream *stream;67 size_t total_out = 0;68 int error = 0;69 zstd_in_buffer in_buf = { NULL, 0, 0 };70 zstd_out_buffer out_buf = { NULL, 0, 0 };71 struct bvec_iter_all iter_all = {};72 struct bio_vec *bvec = bvec_init_iter_all(&iter_all);73 74 stream = zstd_init_dstream(wksp->window_size, wksp->mem, wksp->mem_size);75 76 if (!stream) {77 ERROR("Failed to initialize zstd decompressor\n");78 return -EIO;79 }80 81 out_buf.size = PAGE_SIZE;82 out_buf.dst = squashfs_first_page(output);83 if (IS_ERR(out_buf.dst)) {84 error = PTR_ERR(out_buf.dst);85 goto finish;86 }87 88 for (;;) {89 size_t zstd_err;90 91 if (in_buf.pos == in_buf.size) {92 const void *data;93 int avail;94 95 if (!bio_next_segment(bio, &iter_all)) {96 error = -EIO;97 break;98 }99 100 avail = min(length, ((int)bvec->bv_len) - offset);101 data = bvec_virt(bvec);102 length -= avail;103 in_buf.src = data + offset;104 in_buf.size = avail;105 in_buf.pos = 0;106 offset = 0;107 }108 109 if (out_buf.pos == out_buf.size) {110 out_buf.dst = squashfs_next_page(output);111 if (IS_ERR(out_buf.dst)) {112 error = PTR_ERR(out_buf.dst);113 break;114 } else if (out_buf.dst == NULL) {115 /* Shouldn't run out of pages116 * before stream is done.117 */118 error = -EIO;119 break;120 }121 out_buf.pos = 0;122 out_buf.size = PAGE_SIZE;123 }124 125 total_out -= out_buf.pos;126 zstd_err = zstd_decompress_stream(stream, &out_buf, &in_buf);127 total_out += out_buf.pos; /* add the additional data produced */128 if (zstd_err == 0)129 break;130 131 if (zstd_is_error(zstd_err)) {132 ERROR("zstd decompression error: %d\n",133 (int)zstd_get_error_code(zstd_err));134 error = -EIO;135 break;136 }137 }138 139finish:140 141 squashfs_finish_page(output);142 143 return error ? error : total_out;144}145 146const struct squashfs_decompressor squashfs_zstd_comp_ops = {147 .init = zstd_init,148 .free = zstd_free,149 .decompress = zstd_uncompress,150 .id = ZSTD_COMPRESSION,151 .name = "zstd",152 .alloc_buffer = 1,153 .supported = 1154};155