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