linux/fs/ubifs/compress.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * This file is part of UBIFS.
   4 *
   5 * Copyright (C) 2006-2008 Nokia Corporation.
   6 * Copyright (C) 2006, 2007 University of Szeged, Hungary
   7 *
   8 * Authors: Adrian Hunter
   9 *          Artem Bityutskiy (Битюцкий Артём)
  10 *          Zoltan Sogor
  11 */
  12
  13/*
  14 * This file provides a single place to access to compression and
  15 * decompression.
  16 */
  17
  18#include <linux/crypto.h>
  19#include "ubifs.h"
  20
  21/* Fake description object for the "none" compressor */
  22static struct ubifs_compressor none_compr = {
  23        .compr_type = UBIFS_COMPR_NONE,
  24        .name = "none",
  25        .capi_name = "",
  26};
  27
  28#ifdef CONFIG_UBIFS_FS_LZO
  29static DEFINE_MUTEX(lzo_mutex);
  30
  31static struct ubifs_compressor lzo_compr = {
  32        .compr_type = UBIFS_COMPR_LZO,
  33        .comp_mutex = &lzo_mutex,
  34        .name = "lzo",
  35        .capi_name = "lzo",
  36};
  37#else
  38static struct ubifs_compressor lzo_compr = {
  39        .compr_type = UBIFS_COMPR_LZO,
  40        .name = "lzo",
  41};
  42#endif
  43
  44#ifdef CONFIG_UBIFS_FS_ZLIB
  45static DEFINE_MUTEX(deflate_mutex);
  46static DEFINE_MUTEX(inflate_mutex);
  47
  48static struct ubifs_compressor zlib_compr = {
  49        .compr_type = UBIFS_COMPR_ZLIB,
  50        .comp_mutex = &deflate_mutex,
  51        .decomp_mutex = &inflate_mutex,
  52        .name = "zlib",
  53        .capi_name = "deflate",
  54};
  55#else
  56static struct ubifs_compressor zlib_compr = {
  57        .compr_type = UBIFS_COMPR_ZLIB,
  58        .name = "zlib",
  59};
  60#endif
  61
  62#ifdef CONFIG_UBIFS_FS_ZSTD
  63static DEFINE_MUTEX(zstd_enc_mutex);
  64static DEFINE_MUTEX(zstd_dec_mutex);
  65
  66static struct ubifs_compressor zstd_compr = {
  67        .compr_type = UBIFS_COMPR_ZSTD,
  68        .comp_mutex = &zstd_enc_mutex,
  69        .decomp_mutex = &zstd_dec_mutex,
  70        .name = "zstd",
  71        .capi_name = "zstd",
  72};
  73#else
  74static struct ubifs_compressor zstd_compr = {
  75        .compr_type = UBIFS_COMPR_ZSTD,
  76        .name = "zstd",
  77};
  78#endif
  79
  80/* All UBIFS compressors */
  81struct ubifs_compressor *ubifs_compressors[UBIFS_COMPR_TYPES_CNT];
  82
  83/**
  84 * ubifs_compress - compress data.
  85 * @in_buf: data to compress
  86 * @in_len: length of the data to compress
  87 * @out_buf: output buffer where compressed data should be stored
  88 * @out_len: output buffer length is returned here
  89 * @compr_type: type of compression to use on enter, actually used compression
  90 *              type on exit
  91 *
  92 * This function compresses input buffer @in_buf of length @in_len and stores
  93 * the result in the output buffer @out_buf and the resulting length in
  94 * @out_len. If the input buffer does not compress, it is just copied to the
  95 * @out_buf. The same happens if @compr_type is %UBIFS_COMPR_NONE or if
  96 * compression error occurred.
  97 *
  98 * Note, if the input buffer was not compressed, it is copied to the output
  99 * buffer and %UBIFS_COMPR_NONE is returned in @compr_type.
 100 */
 101void ubifs_compress(const struct ubifs_info *c, const void *in_buf,
 102                    int in_len, void *out_buf, int *out_len, int *compr_type)
 103{
 104        int err;
 105        struct ubifs_compressor *compr = ubifs_compressors[*compr_type];
 106
 107        if (*compr_type == UBIFS_COMPR_NONE)
 108                goto no_compr;
 109
 110        /* If the input data is small, do not even try to compress it */
 111        if (in_len < UBIFS_MIN_COMPR_LEN)
 112                goto no_compr;
 113
 114        if (compr->comp_mutex)
 115                mutex_lock(compr->comp_mutex);
 116        err = crypto_comp_compress(compr->cc, in_buf, in_len, out_buf,
 117                                   (unsigned int *)out_len);
 118        if (compr->comp_mutex)
 119                mutex_unlock(compr->comp_mutex);
 120        if (unlikely(err)) {
 121                ubifs_warn(c, "cannot compress %d bytes, compressor %s, error %d, leave data uncompressed",
 122                           in_len, compr->name, err);
 123                goto no_compr;
 124        }
 125
 126        /*
 127         * If the data compressed only slightly, it is better to leave it
 128         * uncompressed to improve read speed.
 129         */
 130        if (in_len - *out_len < UBIFS_MIN_COMPRESS_DIFF)
 131                goto no_compr;
 132
 133        return;
 134
 135no_compr:
 136        memcpy(out_buf, in_buf, in_len);
 137        *out_len = in_len;
 138        *compr_type = UBIFS_COMPR_NONE;
 139}
 140
 141/**
 142 * ubifs_decompress - decompress data.
 143 * @in_buf: data to decompress
 144 * @in_len: length of the data to decompress
 145 * @out_buf: output buffer where decompressed data should
 146 * @out_len: output length is returned here
 147 * @compr_type: type of compression
 148 *
 149 * This function decompresses data from buffer @in_buf into buffer @out_buf.
 150 * The length of the uncompressed data is returned in @out_len. This functions
 151 * returns %0 on success or a negative error code on failure.
 152 */
 153int ubifs_decompress(const struct ubifs_info *c, const void *in_buf,
 154                     int in_len, void *out_buf, int *out_len, int compr_type)
 155{
 156        int err;
 157        struct ubifs_compressor *compr;
 158
 159        if (unlikely(compr_type < 0 || compr_type >= UBIFS_COMPR_TYPES_CNT)) {
 160                ubifs_err(c, "invalid compression type %d", compr_type);
 161                return -EINVAL;
 162        }
 163
 164        compr = ubifs_compressors[compr_type];
 165
 166        if (unlikely(!compr->capi_name)) {
 167                ubifs_err(c, "%s compression is not compiled in", compr->name);
 168                return -EINVAL;
 169        }
 170
 171        if (compr_type == UBIFS_COMPR_NONE) {
 172                memcpy(out_buf, in_buf, in_len);
 173                *out_len = in_len;
 174                return 0;
 175        }
 176
 177        if (compr->decomp_mutex)
 178                mutex_lock(compr->decomp_mutex);
 179        err = crypto_comp_decompress(compr->cc, in_buf, in_len, out_buf,
 180                                     (unsigned int *)out_len);
 181        if (compr->decomp_mutex)
 182                mutex_unlock(compr->decomp_mutex);
 183        if (err)
 184                ubifs_err(c, "cannot decompress %d bytes, compressor %s, error %d",
 185                          in_len, compr->name, err);
 186
 187        return err;
 188}
 189
 190/**
 191 * compr_init - initialize a compressor.
 192 * @compr: compressor description object
 193 *
 194 * This function initializes the requested compressor and returns zero in case
 195 * of success or a negative error code in case of failure.
 196 */
 197static int __init compr_init(struct ubifs_compressor *compr)
 198{
 199        if (compr->capi_name) {
 200                compr->cc = crypto_alloc_comp(compr->capi_name, 0, 0);
 201                if (IS_ERR(compr->cc)) {
 202                        pr_err("UBIFS error (pid %d): cannot initialize compressor %s, error %ld",
 203                               current->pid, compr->name, PTR_ERR(compr->cc));
 204                        return PTR_ERR(compr->cc);
 205                }
 206        }
 207
 208        ubifs_compressors[compr->compr_type] = compr;
 209        return 0;
 210}
 211
 212/**
 213 * compr_exit - de-initialize a compressor.
 214 * @compr: compressor description object
 215 */
 216static void compr_exit(struct ubifs_compressor *compr)
 217{
 218        if (compr->capi_name)
 219                crypto_free_comp(compr->cc);
 220        return;
 221}
 222
 223/**
 224 * ubifs_compressors_init - initialize UBIFS compressors.
 225 *
 226 * This function initializes the compressor which were compiled in. Returns
 227 * zero in case of success and a negative error code in case of failure.
 228 */
 229int __init ubifs_compressors_init(void)
 230{
 231        int err;
 232
 233        err = compr_init(&lzo_compr);
 234        if (err)
 235                return err;
 236
 237        err = compr_init(&zstd_compr);
 238        if (err)
 239                goto out_lzo;
 240
 241        err = compr_init(&zlib_compr);
 242        if (err)
 243                goto out_zstd;
 244
 245        ubifs_compressors[UBIFS_COMPR_NONE] = &none_compr;
 246        return 0;
 247
 248out_zstd:
 249        compr_exit(&zstd_compr);
 250out_lzo:
 251        compr_exit(&lzo_compr);
 252        return err;
 253}
 254
 255/**
 256 * ubifs_compressors_exit - de-initialize UBIFS compressors.
 257 */
 258void ubifs_compressors_exit(void)
 259{
 260        compr_exit(&lzo_compr);
 261        compr_exit(&zlib_compr);
 262        compr_exit(&zstd_compr);
 263}
 264
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