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.gnu.org/licenses/gpl-2.0.html
  19  *
  20  * GPL HEADER END
  21  */
  22 /*
  23  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
  24  * Use is subject to license terms.
  25  *
  26  * Copyright (c) 2014, Intel Corporation.
  27  */
  28 /*
  29  * This file is part of Lustre, http://www.lustre.org/
  30  * Lustre is a trademark of Sun Microsystems, Inc.
  31  */
  32
  33 #ifndef __OBD_CKSUM
  34 #define __OBD_CKSUM
  35 #include <libcfs/libcfs.h>
  36 #include <libcfs/libcfs_crypto.h>
  37 #include <lustre/lustre_idl.h>
  38
  39 static inline unsigned char cksum_obd2cfs(cksum_type_t cksum_type)
  40 {
  41         switch (cksum_type) {
  42         case OBD_CKSUM_CRC32:
  43                 return CFS_HASH_ALG_CRC32;
  44         case OBD_CKSUM_ADLER:
  45                 return CFS_HASH_ALG_ADLER32;
  46         case OBD_CKSUM_CRC32C:
  47                 return CFS_HASH_ALG_CRC32C;
  48         default:
  49                 CERROR("Unknown checksum type (%x)!!!\n", cksum_type);
  50                 LBUG();
  51         }
  52         return 0;
  53 }
  54
  55 /* The OBD_FL_CKSUM_* flags is packed into 5 bits of o_flags, since there can
  56  * only be a single checksum type per RPC.
  57  *
  58  * The OBD_CHECKSUM_* type bits passed in ocd_cksum_types are a 32-bit bitmask
  59  * since they need to represent the full range of checksum algorithms that
  60  * both the client and server can understand.
  61  *
  62  * In case of an unsupported types/flags we fall back to ADLER
  63  * because that is supported by all clients since 1.8
  64  *
  65  * In case multiple algorithms are supported the best one is used. */
  66 static inline u32 cksum_type_pack(cksum_type_t cksum_type)
  67 {
  68         unsigned int    performance = 0, tmp;
  69         u32             flag = OBD_FL_CKSUM_ADLER;
  70
  71         if (cksum_type & OBD_CKSUM_CRC32) {
  72                 tmp = cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_CRC32));
  73                 if (tmp > performance) {
  74                         performance = tmp;
  75                         flag = OBD_FL_CKSUM_CRC32;
  76                 }
  77         }
  78         if (cksum_type & OBD_CKSUM_CRC32C) {
  79                 tmp = cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_CRC32C));
  80                 if (tmp > performance) {
  81                         performance = tmp;
  82                         flag = OBD_FL_CKSUM_CRC32C;
  83                 }
  84         }
  85         if (cksum_type & OBD_CKSUM_ADLER) {
  86                 tmp = cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_ADLER));
  87                 if (tmp > performance) {
  88                         performance = tmp;
  89                         flag = OBD_FL_CKSUM_ADLER;
  90                 }
  91         }
  92         if (unlikely(cksum_type && !(cksum_type & (OBD_CKSUM_CRC32C |
  93                                                    OBD_CKSUM_CRC32 |
  94                                                    OBD_CKSUM_ADLER))))
  95                 CWARN("unknown cksum type %x\n", cksum_type);
  96
  97         return flag;
  98 }
  99
 100 static inline cksum_type_t cksum_type_unpack(u32 o_flags)
 101 {
 102         switch (o_flags & OBD_FL_CKSUM_ALL) {
 103         case OBD_FL_CKSUM_CRC32C:
 104                 return OBD_CKSUM_CRC32C;
 105         case OBD_FL_CKSUM_CRC32:
 106                 return OBD_CKSUM_CRC32;
 107         default:
 108                 break;
 109         }
 110
 111         return OBD_CKSUM_ADLER;
 112 }
 113
 114 /* Return a bitmask of the checksum types supported on this system.
 115  * 1.8 supported ADLER it is base and not depend on hw
 116  * Client uses all available local algos
 117  */
 118 static inline cksum_type_t cksum_types_supported_client(void)
 119 {
 120         cksum_type_t ret = OBD_CKSUM_ADLER;
 121
 122         CDEBUG(D_INFO, "Crypto hash speed: crc %d, crc32c %d, adler %d\n",
 123                cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_CRC32)),
 124                cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_CRC32C)),
 125                cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_ADLER)));
 126
 127         if (cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_CRC32C)) > 0)
 128                 ret |= OBD_CKSUM_CRC32C;
 129         if (cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_CRC32)) > 0)
 130                 ret |= OBD_CKSUM_CRC32;
 131
 132         return ret;
 133 }
 134
 135 /* Server uses algos that perform at 50% or better of the Adler */
 136 static inline cksum_type_t cksum_types_supported_server(void)
 137 {
 138         int          base_speed;
 139         cksum_type_t    ret = OBD_CKSUM_ADLER;
 140
 141         CDEBUG(D_INFO, "Crypto hash speed: crc %d, crc32c %d, adler %d\n",
 142                cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_CRC32)),
 143                cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_CRC32C)),
 144                cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_ADLER)));
 145
 146         base_speed = cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_ADLER)) / 2;
 147
 148         if (cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_CRC32C)) >=
 149             base_speed)
 150                 ret |= OBD_CKSUM_CRC32C;
 151         if (cfs_crypto_hash_speed(cksum_obd2cfs(OBD_CKSUM_CRC32)) >=
 152             base_speed)
 153                 ret |= OBD_CKSUM_CRC32;
 154
 155         return ret;
 156 }
 157
 158
 159 /* Select the best checksum algorithm among those supplied in the cksum_types
 160  * input.
 161  *
 162  * Currently, calling cksum_type_pack() with a mask will return the fastest
 163  * checksum type due to its benchmarking at libcfs module load.
 164  * Caution is advised, however, since what is fastest on a single client may
 165  * not be the fastest or most efficient algorithm on the server.  */
 166 static inline cksum_type_t cksum_type_select(cksum_type_t cksum_types)
 167 {
 168         return cksum_type_unpack(cksum_type_pack(cksum_types));
 169 }
 170
 171 /* Checksum algorithm names. Must be defined in the same order as the
 172  * OBD_CKSUM_* flags. */
 173 #define DECLARE_CKSUM_NAME char *cksum_name[] = {"crc32", "adler", "crc32c"}
 174
 175 #endif /* __OBD_H */