module/spl/spl-zlib.c

   1 /*****************************************************************************\
   2  *  Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
   3  *  Copyright (C) 2007 The Regents of the University of California.
   4  *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
   5  *  Written by Brian Behlendorf <behlendorf1@llnl.gov>.
   6  *  UCRL-CODE-235197
   7  *
   8  *  This file is part of the SPL, Solaris Porting Layer.
   9  *  For details, see <http://zfsonlinux.org/>.
  10  *
  11  *  The SPL is free software; you can redistribute it and/or modify it
  12  *  under the terms of the GNU General Public License as published by the
  13  *  Free Software Foundation; either version 2 of the License, or (at your
  14  *  option) any later version.
  15  *
  16  *  The SPL is distributed in the hope that it will be useful, but WITHOUT
  17  *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  18  *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  19  *  for more details.
  20  *
  21  *  You should have received a copy of the GNU General Public License along
  22  *  with the SPL.  If not, see <http://www.gnu.org/licenses/>.
  23  *
  24  *
  25  *  z_compress_level/z_uncompress are nearly identical copies of the
  26  *  compress2/uncompress functions provided by the official zlib package
  27  *  available at http://zlib.net/.  The only changes made we to slightly
  28  *  adapt the functions called to match the linux kernel implementation
  29  *  of zlib.  The full zlib license follows:
  30  *
  31  *  zlib.h -- interface of the 'zlib' general purpose compression library
  32  *  version 1.2.5, April 19th, 2010
  33  *
  34  *  Copyright (C) 1995-2010 Jean-loup Gailly and Mark Adler
  35  *
  36  *  This software is provided 'as-is', without any express or implied
  37  *  warranty.  In no event will the authors be held liable for any damages
  38  *  arising from the use of this software.
  39  *
  40  *  Permission is granted to anyone to use this software for any purpose,
  41  *  including commercial applications, and to alter it and redistribute it
  42  *  freely, subject to the following restrictions:
  43  *
  44  *  1. The origin of this software must not be misrepresented; you must not
  45  *     claim that you wrote the original software. If you use this software
  46  *     in a product, an acknowledgment in the product documentation would be
  47  *     appreciated but is not required.
  48  *  2. Altered source versions must be plainly marked as such, and must not be
  49  *     misrepresented as being the original software.
  50  *  3. This notice may not be removed or altered from any source distribution.
  51  *
  52  *  Jean-loup Gailly
  53  *  Mark Adler
  54 \*****************************************************************************/
  55
  56
  57 #include <sys/kmem.h>
  58 #include <sys/kmem_cache.h>
  59 #include <sys/zmod.h>
  60 #include <linux/zlib_compat.h>
  61
  62 static spl_kmem_cache_t *zlib_workspace_cache;
  63
  64 /*
  65  * A kmem_cache is used for the zlib workspaces to avoid having to vmalloc
  66  * and vfree for every call.  Using a kmem_cache also has the advantage
  67  * that improves the odds that the memory used will be local to this cpu.
  68  * To further improve things it might be wise to create a dedicated per-cpu
  69  * workspace for use.  This would take some additional care because we then
  70  * must disable preemption around the critical section, and verify that
  71  * zlib_deflate* and zlib_inflate* never internally call schedule().
  72  */
  73 static void *
  74 zlib_workspace_alloc(int flags)
  75 {
  76         return (kmem_cache_alloc(zlib_workspace_cache, flags & ~(__GFP_FS)));
  77 }
  78
  79 static void
  80 zlib_workspace_free(void *workspace)
  81 {
  82         kmem_cache_free(zlib_workspace_cache, workspace);
  83 }
  84
  85 /*
  86  * Compresses the source buffer into the destination buffer. The level
  87  * parameter has the same meaning as in deflateInit.  sourceLen is the byte
  88  * length of the source buffer. Upon entry, destLen is the total size of the
  89  * destination buffer, which must be at least 0.1% larger than sourceLen plus
  90  * 12 bytes. Upon exit, destLen is the actual size of the compressed buffer.
  91  *
  92  * compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
  93  * memory, Z_BUF_ERROR if there was not enough room in the output buffer,
  94  * Z_STREAM_ERROR if the level parameter is invalid.
  95  */
  96 int
  97 z_compress_level(void *dest, size_t *destLen, const void *source,
  98     size_t sourceLen, int level)
  99 {
 100         z_stream stream;
 101         int err;
 102
 103         stream.next_in = (Byte *)source;
 104         stream.avail_in = (uInt)sourceLen;
 105         stream.next_out = dest;
 106         stream.avail_out = (uInt)*destLen;
 107
 108         if ((size_t)stream.avail_out != *destLen)
 109                 return (Z_BUF_ERROR);
 110
 111         stream.workspace = zlib_workspace_alloc(KM_SLEEP);
 112         if (!stream.workspace)
 113                 return (Z_MEM_ERROR);
 114
 115         err = zlib_deflateInit(&stream, level);
 116         if (err != Z_OK) {
 117                 zlib_workspace_free(stream.workspace);
 118                 return (err);
 119         }
 120
 121         err = zlib_deflate(&stream, Z_FINISH);
 122         if (err != Z_STREAM_END) {
 123                 zlib_deflateEnd(&stream);
 124                 zlib_workspace_free(stream.workspace);
 125                 return (err == Z_OK ? Z_BUF_ERROR : err);
 126         }
 127         *destLen = stream.total_out;
 128
 129         err = zlib_deflateEnd(&stream);
 130         zlib_workspace_free(stream.workspace);
 131
 132         return (err);
 133 }
 134 EXPORT_SYMBOL(z_compress_level);
 135
 136 /*
 137  * Decompresses the source buffer into the destination buffer.  sourceLen is
 138  * the byte length of the source buffer. Upon entry, destLen is the total
 139  * size of the destination buffer, which must be large enough to hold the
 140  * entire uncompressed data. (The size of the uncompressed data must have
 141  * been saved previously by the compressor and transmitted to the decompressor
 142  * by some mechanism outside the scope of this compression library.)
 143  * Upon exit, destLen is the actual size of the compressed buffer.
 144  * This function can be used to decompress a whole file at once if the
 145  * input file is mmap'ed.
 146  *
 147  * uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
 148  * enough memory, Z_BUF_ERROR if there was not enough room in the output
 149  * buffer, or Z_DATA_ERROR if the input data was corrupted.
 150  */
 151 int
 152 z_uncompress(void *dest, size_t *destLen, const void *source, size_t sourceLen)
 153 {
 154         z_stream stream;
 155         int err;
 156
 157         stream.next_in = (Byte *)source;
 158         stream.avail_in = (uInt)sourceLen;
 159         stream.next_out = dest;
 160         stream.avail_out = (uInt)*destLen;
 161
 162         if ((size_t)stream.avail_out != *destLen)
 163                 return (Z_BUF_ERROR);
 164
 165         stream.workspace = zlib_workspace_alloc(KM_SLEEP);
 166         if (!stream.workspace)
 167                 return (Z_MEM_ERROR);
 168
 169         err = zlib_inflateInit(&stream);
 170         if (err != Z_OK) {
 171                 zlib_workspace_free(stream.workspace);
 172                 return (err);
 173         }
 174
 175         err = zlib_inflate(&stream, Z_FINISH);
 176         if (err != Z_STREAM_END) {
 177                 zlib_inflateEnd(&stream);
 178                 zlib_workspace_free(stream.workspace);
 179
 180                 if (err == Z_NEED_DICT ||
 181                     (err == Z_BUF_ERROR && stream.avail_in == 0))
 182                         return (Z_DATA_ERROR);
 183
 184                 return (err);
 185         }
 186         *destLen = stream.total_out;
 187
 188         err = zlib_inflateEnd(&stream);
 189         zlib_workspace_free(stream.workspace);
 190
 191         return (err);
 192 }
 193 EXPORT_SYMBOL(z_uncompress);
 194
 195 int
 196 spl_zlib_init(void)
 197 {
 198         int size;
 199
 200         size = MAX(spl_zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
 201             zlib_inflate_workspacesize());
 202
 203         zlib_workspace_cache = kmem_cache_create(
 204             "spl_zlib_workspace_cache",
 205             size, 0, NULL, NULL, NULL, NULL, NULL,
 206             KMC_VMEM | KMC_NOEMERGENCY);
 207         if (!zlib_workspace_cache)
 208                 return (1);
 209
 210         return (0);
 211 }
 212
 213 void
 214 spl_zlib_fini(void)
 215 {
 216         kmem_cache_destroy(zlib_workspace_cache);
 217         zlib_workspace_cache = NULL;
 218 }