lustre/obdclass/integrity.c

   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) 2018, DataDirect Networks Storage.
  24  * Author: Li Xi.
  25  *
  26  * General data integrity functions
  27  */
  28 #include <linux/blkdev.h>
  29 #include <linux/crc-t10dif.h>
  30 #include <asm/checksum.h>
  31 #include <obd_class.h>
  32 #include <obd_cksum.h>
  33
  34 __u16 obd_dif_crc_fn(void *data, unsigned int len)
  35 {
  36         return cpu_to_be16(crc_t10dif(data, len));
  37 }
  38 EXPORT_SYMBOL(obd_dif_crc_fn);
  39
  40 __u16 obd_dif_ip_fn(void *data, unsigned int len)
  41 {
  42         return ip_compute_csum(data, len);
  43 }
  44 EXPORT_SYMBOL(obd_dif_ip_fn);
  45
  46 int obd_page_dif_generate_buffer(const char *obd_name, struct page *page,
  47                                  __u32 offset, __u32 length,
  48                                  __u16 *guard_start, int guard_number,
  49                                  int *used_number, int sector_size,
  50                                  obd_dif_csum_fn *fn)
  51 {
  52         unsigned int i;
  53         char *data_buf;
  54         __u16 *guard_buf = guard_start;
  55         unsigned int data_size;
  56         int used = 0;
  57
  58         data_buf = kmap(page) + offset;
  59         for (i = 0; i < length; i += sector_size) {
  60                 if (used >= guard_number) {
  61                         CERROR("%s: unexpected used guard number of DIF %u/%u, "
  62                                "data length %u, sector size %u: rc = %d\n",
  63                                obd_name, used, guard_number, length,
  64                                sector_size, -E2BIG);
  65                         return -E2BIG;
  66                 }
  67                 data_size = length - i;
  68                 if (data_size > sector_size)
  69                         data_size = sector_size;
  70                 *guard_buf = fn(data_buf, data_size);
  71                 guard_buf++;
  72                 data_buf += data_size;
  73                 used++;
  74         }
  75         kunmap(page);
  76         *used_number = used;
  77
  78         return 0;
  79 }
  80 EXPORT_SYMBOL(obd_page_dif_generate_buffer);
  81
  82 static int __obd_t10_performance_test(const char *obd_name,
  83                                       enum cksum_types cksum_type,
  84                                       struct page *data_page,
  85                                       int repeat_number)
  86 {
  87         unsigned char cfs_alg = cksum_obd2cfs(OBD_CKSUM_T10_TOP);
  88         struct cfs_crypto_hash_desc *hdesc;
  89         obd_dif_csum_fn *fn = NULL;
  90         unsigned int bufsize;
  91         unsigned char *buffer;
  92         struct page *__page;
  93         __u16 *guard_start;
  94         int guard_number;
  95         int used_number = 0;
  96         int sector_size = 0;
  97         __u32 cksum;
  98         int rc = 0;
  99         int rc2;
 100         int used;
 101         int i;
 102
 103         obd_t10_cksum2dif(cksum_type, &fn, &sector_size);
 104         if (!fn)
 105                 return -EINVAL;
 106
 107         __page = alloc_page(GFP_KERNEL);
 108         if (__page == NULL)
 109                 return -ENOMEM;
 110
 111         hdesc = cfs_crypto_hash_init(cfs_alg, NULL, 0);
 112         if (IS_ERR(hdesc)) {
 113                 rc = PTR_ERR(hdesc);
 114                 CERROR("%s: unable to initialize checksum hash %s: rc = %d\n",
 115                        obd_name, cfs_crypto_hash_name(cfs_alg), rc);
 116                 GOTO(out, rc);
 117         }
 118
 119         buffer = kmap(__page);
 120         guard_start = (__u16 *)buffer;
 121         guard_number = PAGE_SIZE / sizeof(*guard_start);
 122         for (i = 0; i < repeat_number; i++) {
 123                 /*
 124                  * The left guard number should be able to hold checksums of a
 125                  * whole page
 126                  */
 127                 rc = obd_page_dif_generate_buffer(obd_name, data_page, 0,
 128                                                   PAGE_SIZE,
 129                                                   guard_start + used_number,
 130                                                   guard_number - used_number,
 131                                                   &used, sector_size, fn);
 132                 if (rc)
 133                         break;
 134
 135                 used_number += used;
 136                 if (used_number == guard_number) {
 137                         cfs_crypto_hash_update_page(hdesc, __page, 0,
 138                                 used_number * sizeof(*guard_start));
 139                         used_number = 0;
 140                 }
 141         }
 142         kunmap(__page);
 143         if (rc)
 144                 GOTO(out_final, rc);
 145
 146         if (used_number != 0)
 147                 cfs_crypto_hash_update_page(hdesc, __page, 0,
 148                         used_number * sizeof(*guard_start));
 149
 150         bufsize = sizeof(cksum);
 151 out_final:
 152         rc2 = cfs_crypto_hash_final(hdesc, (unsigned char *)&cksum, &bufsize);
 153         rc = rc ? rc : rc2;
 154 out:
 155         __free_page(__page);
 156
 157         return rc;
 158 }
 159
 160 /**
 161  *  Array of T10PI checksum algorithm speed in MByte per second
 162  */
 163 static int obd_t10_cksum_speeds[OBD_T10_CKSUM_MAX];
 164
 165 static enum obd_t10_cksum_type
 166 obd_t10_cksum2type(enum cksum_types cksum_type)
 167 {
 168         switch (cksum_type) {
 169         case OBD_CKSUM_T10IP512:
 170                 return OBD_T10_CKSUM_IP512;
 171         case OBD_CKSUM_T10IP4K:
 172                 return OBD_T10_CKSUM_IP4K;
 173         case OBD_CKSUM_T10CRC512:
 174                 return OBD_T10_CKSUM_CRC512;
 175         case OBD_CKSUM_T10CRC4K:
 176                 return OBD_T10_CKSUM_CRC4K;
 177         default:
 178                 return OBD_T10_CKSUM_UNKNOWN;
 179         }
 180 }
 181
 182 static const char *obd_t10_cksum_name(enum obd_t10_cksum_type index)
 183 {
 184         DECLARE_CKSUM_NAME;
 185
 186         /* Need to skip "crc32", "adler", "crc32c", "reserved" */
 187         return cksum_name[3 + index];
 188 }
 189
 190 /**
 191  * Compute the speed of specified T10PI checksum type
 192  *
 193  * Run a speed test on the given T10PI checksum on buffer using a 1MB buffer
 194  * size. This is a reasonable buffer size for Lustre RPCs, even if the actual
 195  * RPC size is larger or smaller.
 196  *
 197  * The speed is stored internally in the obd_t10_cksum_speeds[] array, and
 198  * is available through the obd_t10_cksum_speed() function.
 199  *
 200  * This function needs to stay the same as cfs_crypto_performance_test() so
 201  * that the speeds are comparable. And this function should reflect the real
 202  * cost of the checksum calculation.
 203  *
 204  * \param[in] obd_name          name of the OBD device
 205  * \param[in] cksum_type        checksum type (OBD_CKSUM_T10*)
 206  */
 207 static void obd_t10_performance_test(const char *obd_name,
 208                                      enum cksum_types cksum_type)
 209 {
 210         enum obd_t10_cksum_type index = obd_t10_cksum2type(cksum_type);
 211         const int buf_len = max(PAGE_SIZE, 1048576UL);
 212         unsigned long bcount;
 213         unsigned long start;
 214         unsigned long end;
 215         struct page *page;
 216         int rc = 0;
 217         void *buf;
 218
 219         page = alloc_page(GFP_KERNEL);
 220         if (page == NULL) {
 221                 rc = -ENOMEM;
 222                 goto out;
 223         }
 224
 225         buf = kmap(page);
 226         memset(buf, 0xAD, PAGE_SIZE);
 227         kunmap(page);
 228
 229         for (start = jiffies, end = start + msecs_to_jiffies(MSEC_PER_SEC / 4),
 230              bcount = 0; time_before(jiffies, end) && rc == 0; bcount++) {
 231                 rc = __obd_t10_performance_test(obd_name, cksum_type, page,
 232                                                 buf_len / PAGE_SIZE);
 233                 if (rc)
 234                         break;
 235         }
 236         end = jiffies;
 237         __free_page(page);
 238 out:
 239         if (rc) {
 240                 obd_t10_cksum_speeds[index] = rc;
 241                 CDEBUG(D_INFO, "%s: T10 checksum algorithm %s test error: "
 242                        "rc = %d\n", obd_name, obd_t10_cksum_name(index), rc);
 243         } else {
 244                 unsigned long tmp;
 245
 246                 tmp = ((bcount * buf_len / jiffies_to_msecs(end - start)) *
 247                        1000) / (1024 * 1024);
 248                 obd_t10_cksum_speeds[index] = (int)tmp;
 249                 CDEBUG(D_CONFIG, "%s: T10 checksum algorithm %s speed = %d "
 250                        "MB/s\n", obd_name, obd_t10_cksum_name(index),
 251                        obd_t10_cksum_speeds[index]);
 252         }
 253 }
 254
 255 int obd_t10_cksum_speed(const char *obd_name,
 256                         enum cksum_types cksum_type)
 257 {
 258         enum obd_t10_cksum_type index = obd_t10_cksum2type(cksum_type);
 259
 260         if (unlikely(obd_t10_cksum_speeds[index] == 0)) {
 261                 static DEFINE_MUTEX(obd_t10_cksum_speed_mutex);
 262
 263                 mutex_lock(&obd_t10_cksum_speed_mutex);
 264                 if (obd_t10_cksum_speeds[index] == 0)
 265                         obd_t10_performance_test(obd_name, cksum_type);
 266                 mutex_unlock(&obd_t10_cksum_speed_mutex);
 267         }
 268
 269         return obd_t10_cksum_speeds[index];
 270 }
 271 EXPORT_SYMBOL(obd_t10_cksum_speed);