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author | Linus Torvalds <torvalds@linux-foundation.org> | 2010-08-10 15:38:19 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-08-10 15:38:19 -0700 |
commit | 3d30701b58970425e1d45994d6cb82f828924fdd (patch) | |
tree | 8b14cf462628bebf8548c1b8c205a674564052d1 /lib/raid6/mktables.c | |
parent | 8cbd84f2dd4e52a8771b191030c374ba3e56d291 (diff) | |
parent | fd8aa2c1811bf60ccb2d5de0579c6f62aec1772d (diff) | |
download | linux-3d30701b58970425e1d45994d6cb82f828924fdd.tar.gz linux-3d30701b58970425e1d45994d6cb82f828924fdd.tar.bz2 linux-3d30701b58970425e1d45994d6cb82f828924fdd.zip |
Merge branch 'for-linus' of git://neil.brown.name/md
* 'for-linus' of git://neil.brown.name/md: (24 commits)
md: clean up do_md_stop
md: fix another deadlock with removing sysfs attributes.
md: move revalidate_disk() back outside open_mutex
md/raid10: fix deadlock with unaligned read during resync
md/bitmap: separate out loading a bitmap from initialising the structures.
md/bitmap: prepare for storing write-intent-bitmap via dm-dirty-log.
md/bitmap: optimise scanning of empty bitmaps.
md/bitmap: clean up plugging calls.
md/bitmap: reduce dependence on sysfs.
md/bitmap: white space clean up and similar.
md/raid5: export raid5 unplugging interface.
md/plug: optionally use plugger to unplug an array during resync/recovery.
md/raid5: add simple plugging infrastructure.
md/raid5: export is_congested test
raid5: Don't set read-ahead when there is no queue
md: add support for raising dm events.
md: export various start/stop interfaces
md: split out md_rdev_init
md: be more careful setting MD_CHANGE_CLEAN
md/raid5: ensure we create a unique name for kmem_cache when mddev has no gendisk
...
Diffstat (limited to 'lib/raid6/mktables.c')
-rw-r--r-- | lib/raid6/mktables.c | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/lib/raid6/mktables.c b/lib/raid6/mktables.c new file mode 100644 index 000000000000..3b1500843bba --- /dev/null +++ b/lib/raid6/mktables.c @@ -0,0 +1,132 @@ +/* -*- linux-c -*- ------------------------------------------------------- * + * + * Copyright 2002-2007 H. Peter Anvin - All Rights Reserved + * + * This file is part of the Linux kernel, and is made available under + * the terms of the GNU General Public License version 2 or (at your + * option) any later version; incorporated herein by reference. + * + * ----------------------------------------------------------------------- */ + +/* + * mktables.c + * + * Make RAID-6 tables. This is a host user space program to be run at + * compile time. + */ + +#include <stdio.h> +#include <string.h> +#include <inttypes.h> +#include <stdlib.h> +#include <time.h> + +static uint8_t gfmul(uint8_t a, uint8_t b) +{ + uint8_t v = 0; + + while (b) { + if (b & 1) + v ^= a; + a = (a << 1) ^ (a & 0x80 ? 0x1d : 0); + b >>= 1; + } + + return v; +} + +static uint8_t gfpow(uint8_t a, int b) +{ + uint8_t v = 1; + + b %= 255; + if (b < 0) + b += 255; + + while (b) { + if (b & 1) + v = gfmul(v, a); + a = gfmul(a, a); + b >>= 1; + } + + return v; +} + +int main(int argc, char *argv[]) +{ + int i, j, k; + uint8_t v; + uint8_t exptbl[256], invtbl[256]; + + printf("#include <linux/raid/pq.h>\n"); + + /* Compute multiplication table */ + printf("\nconst u8 __attribute__((aligned(256)))\n" + "raid6_gfmul[256][256] =\n" + "{\n"); + for (i = 0; i < 256; i++) { + printf("\t{\n"); + for (j = 0; j < 256; j += 8) { + printf("\t\t"); + for (k = 0; k < 8; k++) + printf("0x%02x,%c", gfmul(i, j + k), + (k == 7) ? '\n' : ' '); + } + printf("\t},\n"); + } + printf("};\n"); + printf("#ifdef __KERNEL__\n"); + printf("EXPORT_SYMBOL(raid6_gfmul);\n"); + printf("#endif\n"); + + /* Compute power-of-2 table (exponent) */ + v = 1; + printf("\nconst u8 __attribute__((aligned(256)))\n" + "raid6_gfexp[256] =\n" "{\n"); + for (i = 0; i < 256; i += 8) { + printf("\t"); + for (j = 0; j < 8; j++) { + exptbl[i + j] = v; + printf("0x%02x,%c", v, (j == 7) ? '\n' : ' '); + v = gfmul(v, 2); + if (v == 1) + v = 0; /* For entry 255, not a real entry */ + } + } + printf("};\n"); + printf("#ifdef __KERNEL__\n"); + printf("EXPORT_SYMBOL(raid6_gfexp);\n"); + printf("#endif\n"); + + /* Compute inverse table x^-1 == x^254 */ + printf("\nconst u8 __attribute__((aligned(256)))\n" + "raid6_gfinv[256] =\n" "{\n"); + for (i = 0; i < 256; i += 8) { + printf("\t"); + for (j = 0; j < 8; j++) { + invtbl[i + j] = v = gfpow(i + j, 254); + printf("0x%02x,%c", v, (j == 7) ? '\n' : ' '); + } + } + printf("};\n"); + printf("#ifdef __KERNEL__\n"); + printf("EXPORT_SYMBOL(raid6_gfinv);\n"); + printf("#endif\n"); + + /* Compute inv(2^x + 1) (exponent-xor-inverse) table */ + printf("\nconst u8 __attribute__((aligned(256)))\n" + "raid6_gfexi[256] =\n" "{\n"); + for (i = 0; i < 256; i += 8) { + printf("\t"); + for (j = 0; j < 8; j++) + printf("0x%02x,%c", invtbl[exptbl[i + j] ^ 1], + (j == 7) ? '\n' : ' '); + } + printf("};\n"); + printf("#ifdef __KERNEL__\n"); + printf("EXPORT_SYMBOL(raid6_gfexi);\n"); + printf("#endif\n"); + + return 0; +} |