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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright (c) 2013, 20144 * Phillip Lougher <phillip@squashfs.org.uk>5 */6 7#include <linux/bio.h>8#include <linux/mutex.h>9#include <linux/slab.h>10#include <linux/vmalloc.h>11#include <linux/lz4.h>12 13#include "squashfs_fs.h"14#include "squashfs_fs_sb.h"15#include "squashfs.h"16#include "decompressor.h"17#include "page_actor.h"18 19#define LZ4_LEGACY 120 21struct lz4_comp_opts {22 __le32 version;23 __le32 flags;24};25 26struct squashfs_lz4 {27 void *input;28 void *output;29};30 31 32static void *lz4_comp_opts(struct squashfs_sb_info *msblk,33 void *buff, int len)34{35 struct lz4_comp_opts *comp_opts = buff;36 37 /* LZ4 compressed filesystems always have compression options */38 if (comp_opts == NULL || len < sizeof(*comp_opts))39 return ERR_PTR(-EIO);40 41 if (le32_to_cpu(comp_opts->version) != LZ4_LEGACY) {42 /* LZ4 format currently used by the kernel is the 'legacy'43 * format */44 ERROR("Unknown LZ4 version\n");45 return ERR_PTR(-EINVAL);46 }47 48 return NULL;49}50 51 52static void *lz4_init(struct squashfs_sb_info *msblk, void *buff)53{54 int block_size = max_t(int, msblk->block_size, SQUASHFS_METADATA_SIZE);55 struct squashfs_lz4 *stream;56 57 stream = kzalloc(sizeof(*stream), GFP_KERNEL);58 if (stream == NULL)59 goto failed;60 stream->input = vmalloc(block_size);61 if (stream->input == NULL)62 goto failed2;63 stream->output = vmalloc(block_size);64 if (stream->output == NULL)65 goto failed3;66 67 return stream;68 69failed3:70 vfree(stream->input);71failed2:72 kfree(stream);73failed:74 ERROR("Failed to initialise LZ4 decompressor\n");75 return ERR_PTR(-ENOMEM);76}77 78 79static void lz4_free(void *strm)80{81 struct squashfs_lz4 *stream = strm;82 83 if (stream) {84 vfree(stream->input);85 vfree(stream->output);86 }87 kfree(stream);88}89 90 91static int lz4_uncompress(struct squashfs_sb_info *msblk, void *strm,92 struct bio *bio, int offset, int length,93 struct squashfs_page_actor *output)94{95 struct bvec_iter_all iter_all = {};96 struct bio_vec *bvec = bvec_init_iter_all(&iter_all);97 struct squashfs_lz4 *stream = strm;98 void *buff = stream->input, *data;99 int bytes = length, res;100 101 while (bio_next_segment(bio, &iter_all)) {102 int avail = min(bytes, ((int)bvec->bv_len) - offset);103 104 data = bvec_virt(bvec);105 memcpy(buff, data + offset, avail);106 buff += avail;107 bytes -= avail;108 offset = 0;109 }110 111 res = LZ4_decompress_safe(stream->input, stream->output,112 length, output->length);113 114 if (res < 0)115 return -EIO;116 117 bytes = res;118 data = squashfs_first_page(output);119 buff = stream->output;120 while (data) {121 if (bytes <= PAGE_SIZE) {122 if (!IS_ERR(data))123 memcpy(data, buff, bytes);124 break;125 }126 if (!IS_ERR(data))127 memcpy(data, buff, PAGE_SIZE);128 buff += PAGE_SIZE;129 bytes -= PAGE_SIZE;130 data = squashfs_next_page(output);131 }132 squashfs_finish_page(output);133 134 return res;135}136 137const struct squashfs_decompressor squashfs_lz4_comp_ops = {138 .init = lz4_init,139 .comp_opts = lz4_comp_opts,140 .free = lz4_free,141 .decompress = lz4_uncompress,142 .id = LZ4_COMPRESSION,143 .name = "lz4",144 .alloc_buffer = 0,145 .supported = 1146};147