Copied from kernel code with minor modification.
Signed-off-by: Qu Wenruo <quwen...@cn.fujitsu.com>
---
.gitignore | 2 +
Makefile.in | 12 ++++-
mktables.c | 142 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
raid56.h | 7 +++
4 files changed, 161 insertions(+), 2 deletions(-)
create mode 100644 mktables.c
diff --git a/.gitignore b/.gitignore
index 214103d..2587661 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,6 +2,8 @@
*.static.o
*.o.d
tags
+mktables
+tables.c
.cc-defines.h
version.h
version
diff --git a/Makefile.in b/Makefile.in
index 73b2919..a25cda9 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -93,7 +93,7 @@ objects = ctree.o disk-io.o kernel-lib/radix-tree.o
extent-tree.o print-tree.o \
extent-cache.o extent_io.o volumes.o utils.o repair.o \
qgroup.o raid56.o free-space-cache.o kernel-lib/list_sort.o props.o \
ulist.o qgroup-verify.o backref.o string-table.o task-utils.o \
- inode.o file.o find-root.o free-space-tree.o help.o
+ inode.o file.o find-root.o free-space-tree.o help.o tables.o
cmds_objects = cmds-subvolume.o cmds-filesystem.o cmds-device.o cmds-scrub.o \
cmds-inspect.o cmds-balance.o cmds-send.o cmds-receive.o \
cmds-quota.o cmds-qgroup.o cmds-replace.o cmds-check.o \
@@ -310,6 +310,14 @@ version.h: version.sh version.h.in configure.ac
@echo " [SH] $@"
$(Q)bash ./config.status --silent $@
+mktables: mktables.c
+ @echo " [CC] $@"
+ $(Q)$(CC) $(CFLAGS) $< -o $@
+
+tables.c: mktables
+ @echo " [TABLE] $@"
+ $(Q)./mktables > $@ || ($(RM) -f $@ && exit 1)
+
$(libs_shared): $(libbtrfs_objects) $(lib_links) send.h
@echo " [LD] $@"
$(Q)$(CC) $(CFLAGS) $(libbtrfs_objects) $(LDFLAGS) $(LIBBTRFS_LIBS) \
@@ -430,7 +438,7 @@ clean-all: clean clean-doc clean-gen
clean: $(CLEANDIRS)
@echo "Cleaning"
- $(Q)$(RM) -f -- $(progs) cscope.out *.o *.o.d \
+ $(Q)$(RM) -f -- $(progs) cscope.out *.o *.o.d mktables tables.c \
kernel-lib/*.o kernel-lib/*.o.d \
dir-test ioctl-test quick-test send-test library-test
library-test-static \
btrfs.static mkfs.btrfs.static \
diff --git a/mktables.c b/mktables.c
new file mode 100644
index 0000000..10103f0
--- /dev/null
+++ b/mktables.c
@@ -0,0 +1,142 @@
+/* -*- 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 \"kerncompat.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");
+
+ /* Compute vector multiplication table */
+ printf("\nconst u8 __attribute__((aligned(256)))\n"
+ "raid6_vgfmul[256][32] =\n"
+ "{\n");
+ for (i = 0; i < 256; i++) {
+ printf("\t{\n");
+ for (j = 0; j < 16; j += 8) {
+ printf("\t\t");
+ for (k = 0; k < 8; k++)
+ printf("0x%02x,%c", gfmul(i, j + k),
+ (k == 7) ? '\n' : ' ');
+ }
+ for (j = 0; j < 16; j += 8) {
+ printf("\t\t");
+ for (k = 0; k < 8; k++)
+ printf("0x%02x,%c", gfmul(i, (j + k) << 4),
+ (k == 7) ? '\n' : ' ');
+ }
+ printf("\t},\n");
+ }
+ printf("};\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");
+
+ /* 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");
+
+ /* 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");
+
+ return 0;
+}
diff --git a/raid56.h b/raid56.h
index 54f0cde..a05c14b 100644
--- a/raid56.h
+++ b/raid56.h
@@ -18,3 +18,10 @@
void raid6_gen_syndrome(int disks, size_t bytes, void **ptrs);
int raid5_gen_result(int nr_devs, size_t stripe_len, int dest, void **data);
+
+/* Galois field tables */
+extern const u8 raid6_gfmul[256][256] __attribute__((aligned(256)));
+extern const u8 raid6_vgfmul[256][32] __attribute__((aligned(256)));
+extern const u8 raid6_gfexp[256] __attribute__((aligned(256)));
+extern const u8 raid6_gfinv[256] __attribute__((aligned(256)));
+extern const u8 raid6_gfexi[256] __attribute__((aligned(256)));
--
2.10.1
--
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