lustre/include/obd_cksum.h

   1 /*
   2  * GPL HEADER START
   3  *
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License version 2 for more details (a copy is included
  14  * in the LICENSE file that accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * version 2 along with this program; If not, see
  18  * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
  19  *
  20  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  21  * CA 95054 USA or visit www.sun.com if you need additional information or
  22  * have any questions.
  23  *
  24  * GPL HEADER END
  25  */
  26 /*
  27  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
  28  * Use is subject to license terms.
  29  */
  30 /*
  31  * This file is part of Lustre, http://www.lustre.org/
  32  * Lustre is a trademark of Sun Microsystems, Inc.
  33  */
  34
  35 #ifndef __OBD_CKSUM
  36 #define __OBD_CKSUM
  37 #include <libcfs/libcfs.h>
  38 #include <libcfs/libcfs_crypto.h>
  39 #include <lustre/lustre_idl.h>
  40
  41 static inline unsigned char cksum_obd2cfs(cksum_type_t cksum_type)
  42 {
  43         switch (cksum_type) {
  44         case OBD_CKSUM_CRC32:
  45                 return CFS_HASH_ALG_CRC32;
  46         case OBD_CKSUM_ADLER:
  47                 return CFS_HASH_ALG_ADLER32;
  48         case OBD_CKSUM_CRC32C:
  49                 return CFS_HASH_ALG_CRC32C;
  50         default:
  51                 CERROR("Unknown checksum type (%x)!!!\n", cksum_type);
  52                 LBUG();
  53         }
  54         return 0;
  55 }
  56
  57 /* The OBD_FL_CKSUM_* flags is packed into 5 bits of o_flags, since there can
  58  * only be a single checksum type per RPC.
  59  *
  60  * The OBD_CHECKSUM_* type bits passed in ocd_cksum_types are a 32-bit bitmask
  61  * since they need to represent the full range of checksum algorithms that
  62  * both the client and server can understand.
  63  *
  64  * In case of an unsupported types/flags we fall back to ADLER
  65  * because that is supported by all clients since 1.8
  66  *
  67  * In case multiple algorithms are supported the best one is used. */
  68 static inline u32 cksum_type_pack(cksum_type_t cksum_type)
  69 {
  70         unsigned int    performance = 0, tmp;
  71         u32             flag = OBD_FL_CKSUM_ADLER;
  72
  73         if (cksum_type & OBD_CKSUM_CRC32) {
  74                 tmp = cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_CRC32));
  75                 if (tmp > performance) {
  76                         performance = tmp;
  77                         flag = OBD_FL_CKSUM_CRC32;
  78                 }
  79         }
  80         if (cksum_type & OBD_CKSUM_CRC32C) {
  81                 tmp = cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_CRC32C));
  82                 if (tmp > performance) {
  83                         performance = tmp;
  84                         flag = OBD_FL_CKSUM_CRC32C;
  85                 }
  86         }
  87         if (cksum_type & OBD_CKSUM_ADLER) {
  88                 tmp = cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_ADLER));
  89                 if (tmp > performance) {
  90                         performance = tmp;
  91                         flag = OBD_FL_CKSUM_ADLER;
  92                 }
  93         }
  94         if (unlikely(cksum_type && !(cksum_type & (OBD_CKSUM_CRC32C |
  95                                                    OBD_CKSUM_CRC32 |
  96                                                    OBD_CKSUM_ADLER))))
  97                 CWARN("unknown cksum type %x\n", cksum_type);
  98
  99         return flag;
 100 }
 101
 102 static inline cksum_type_t cksum_type_unpack(u32 o_flags)
 103 {
 104         switch (o_flags & OBD_FL_CKSUM_ALL) {
 105         case OBD_FL_CKSUM_CRC32C:
 106                 return OBD_CKSUM_CRC32C;
 107         case OBD_FL_CKSUM_CRC32:
 108                 return OBD_CKSUM_CRC32;
 109         default:
 110                 break;
 111         }
 112
 113         return OBD_CKSUM_ADLER;
 114 }
 115
 116 /* Return a bitmask of the checksum types supported on this system.
 117  * 1.8 supported ADLER it is base and not depend on hw
 118  * Client uses all available local algos
 119  */
 120 static inline cksum_type_t cksum_types_supported_client(void)
 121 {
 122         cksum_type_t ret = OBD_CKSUM_ADLER;
 123
 124         CDEBUG(D_INFO, "Crypto hash speed: crc %d, crc32c %d, adler %d\n",
 125                cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_CRC32)),
 126                cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_CRC32C)),
 127                cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_ADLER)));
 128
 129         if (cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_CRC32C)) > 0)
 130                 ret |= OBD_CKSUM_CRC32C;
 131         if (cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_CRC32)) > 0)
 132                 ret |= OBD_CKSUM_CRC32;
 133
 134         return ret;
 135 }
 136
 137 /* Server uses algos that perform at 50% or better of the Adler */
 138 static inline cksum_type_t cksum_types_supported_server(void)
 139 {
 140         int          base_speed;
 141         cksum_type_t    ret = OBD_CKSUM_ADLER;
 142
 143         CDEBUG(D_INFO, "Crypto hash speed: crc %d, crc32c %d, adler %d\n",
 144                cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_CRC32)),
 145                cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_CRC32C)),
 146                cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_ADLER)));
 147
 148         base_speed = cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_ADLER)) / 2;
 149
 150         if (cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_CRC32C)) >=
 151             base_speed)
 152                 ret |= OBD_CKSUM_CRC32C;
 153         if (cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_CRC32)) >=
 154             base_speed)
 155                 ret |= OBD_CKSUM_CRC32;
 156
 157         return ret;
 158 }
 159
 160
 161 /* Select the best checksum algorithm among those supplied in the cksum_types
 162  * input.
 163  *
 164  * Currently, calling cksum_type_pack() with a mask will return the fastest
 165  * checksum type due to its benchmarking at libcfs module load.
 166  * Caution is advised, however, since what is fastest on a single client may
 167  * not be the fastest or most efficient algorithm on the server.  */
 168 static inline cksum_type_t cksum_type_select(cksum_type_t cksum_types)
 169 {
 170         return cksum_type_unpack(cksum_type_pack(cksum_types));
 171 }
 172
 173 /* Checksum algorithm names. Must be defined in the same order as the
 174  * OBD_CKSUM_* flags. */
 175 #define DECLARE_CKSUM_NAME char *cksum_name[] = {"crc32", "adler", "crc32c"}
 176
 177 #endif /* __OBD_H */