add crc32c and use it for r5l checksum

In kernel space, r5l checksum will use crc32c:
http://marc.info/?l=linux-raid&m=144598970529191
mdadm need to change too.

This patch ports a simplified crc32c algorithm from kernel code,
and used in super1.c:write_empty_r5l_meta_block();

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
This commit is contained in:
Song Liu 2015-10-28 12:06:06 -07:00 committed by NeilBrown
parent 356e69de79
commit 198d54787c
3 changed files with 109 additions and 8 deletions

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@ -133,7 +133,7 @@ OBJS = mdadm.o config.o policy.o mdstat.o ReadMe.o util.o maps.o lib.o \
mdopen.o super0.o super1.o super-ddf.o super-intel.o bitmap.o \
super-mbr.o super-gpt.o \
restripe.o sysfs.o sha1.o mapfile.o crc32.o sg_io.o msg.o xmalloc.o \
platform-intel.o probe_roms.o
platform-intel.o probe_roms.o crc32c.o
CHECK_OBJS = restripe.o sysfs.o maps.o lib.o xmalloc.o dlink.o

104
crc32c.c Normal file
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@ -0,0 +1,104 @@
/*
* Oct 28, 2015 Song Liu simplified the code and port it to mdadm
*
* Aug 8, 2011 Bob Pearson with help from Joakim Tjernlund and George Spelvin
* cleaned up code to current version of sparse and added the slicing-by-8
* algorithm to the closely similar existing slicing-by-4 algorithm.
*
* Oct 15, 2000 Matt Domsch <Matt_Domsch@dell.com>
* Nicer crc32 functions/docs submitted by linux@horizon.com. Thanks!
* Code was from the public domain, copyright abandoned. Code was
* subsequently included in the kernel, thus was re-licensed under the
* GNU GPL v2.
*
* Oct 12, 2000 Matt Domsch <Matt_Domsch@dell.com>
* Same crc32 function was used in 5 other places in the kernel.
* I made one version, and deleted the others.
* There are various incantations of crc32(). Some use a seed of 0 or ~0.
* Some xor at the end with ~0. The generic crc32() function takes
* seed as an argument, and doesn't xor at the end. Then individual
* users can do whatever they need.
* drivers/net/smc9194.c uses seed ~0, doesn't xor with ~0.
* fs/jffs2 uses seed 0, doesn't xor with ~0.
* fs/partitions/efi.c uses seed ~0, xor's with ~0.
*
* This source code is licensed under the GNU General Public License,
* Version 2. See the file COPYING for more details.
*/
#include <sys/types.h>
#include <asm/types.h>
#include <stdlib.h>
/*
* There are multiple 16-bit CRC polynomials in common use, but this is
* *the* standard CRC-32 polynomial, first popularized by Ethernet.
* x^32+x^26+x^23+x^22+x^16+x^12+x^11+x^10+x^8+x^7+x^5+x^4+x^2+x^1+x^0
*/
#define CRCPOLY_LE 0xedb88320
#define CRCPOLY_BE 0x04c11db7
/*
* This is the CRC32c polynomial, as outlined by Castagnoli.
* x^32+x^28+x^27+x^26+x^25+x^23+x^22+x^20+x^19+x^18+x^14+x^13+x^11+x^10+x^9+
* x^8+x^6+x^0
*/
#define CRC32C_POLY_LE 0x82F63B78
/**
* crc32_le_generic() - Calculate bitwise little-endian Ethernet AUTODIN II
* CRC32/CRC32C
* @crc: seed value for computation. ~0 for Ethernet, sometimes 0 for other
* uses, or the previous crc32/crc32c value if computing incrementally.
* @p: pointer to buffer over which CRC32/CRC32C is run
* @len: length of buffer @p
* @polynomial: CRC32/CRC32c LE polynomial
*/
static inline __u32 crc32_le_generic(__u32 crc, unsigned char const *p,
size_t len, __u32 polynomial)
{
int i;
while (len--) {
crc ^= *p++;
for (i = 0; i < 8; i++)
crc = (crc >> 1) ^ ((crc & 1) ? polynomial : 0);
}
return crc;
}
__u32 crc32_le(__u32 crc, unsigned char const *p, size_t len)
{
return crc32_le_generic(crc, p, len, CRCPOLY_LE);
}
__u32 crc32c_le(__u32 crc, unsigned char const *p, size_t len)
{
return crc32_le_generic(crc, p, len, CRC32C_POLY_LE);
}
/**
* crc32_be_generic() - Calculate bitwise big-endian Ethernet AUTODIN II CRC32
* @crc: seed value for computation. ~0 for Ethernet, sometimes 0 for
* other uses, or the previous crc32 value if computing incrementally.
* @p: pointer to buffer over which CRC32 is run
* @len: length of buffer @p
* @polynomial: CRC32 BE polynomial
*/
static inline __u32 crc32_be_generic(__u32 crc, unsigned char const *p,
size_t len, __u32 polynomial)
{
int i;
while (len--) {
crc ^= *p++ << 24;
for (i = 0; i < 8; i++)
crc =
(crc << 1) ^ ((crc & 0x80000000) ? polynomial :
0);
}
return crc;
}
__u32 crc32_be(__u32 crc, unsigned char const *p, size_t len)
{
return crc32_be_generic(crc, p, len, CRCPOLY_BE);
}

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@ -1625,10 +1625,7 @@ static unsigned long choose_bm_space(unsigned long devsize)
static void free_super1(struct supertype *st);
#define META_BLOCK_SIZE 4096
unsigned long crc32(
unsigned long crc,
const unsigned char *buf,
unsigned len);
__u32 crc32c_le(__u32 crc, unsigned char const *p, size_t len);
static int write_empty_r5l_meta_block(struct supertype *st, int fd)
{
@ -1652,9 +1649,9 @@ static int write_empty_r5l_meta_block(struct supertype *st, int fd)
mb->seq = __cpu_to_le64(random32());
mb->position = __cpu_to_le64(0);
crc = crc32(0xffffffff, sb->set_uuid, sizeof(sb->set_uuid));
crc = crc32(crc, (void *)mb, META_BLOCK_SIZE);
mb->checksum = __cpu_to_le32(crc);
crc = crc32c_le(0xffffffff, sb->set_uuid, sizeof(sb->set_uuid));
crc = crc32c_le(crc, (void *)mb, META_BLOCK_SIZE);
mb->checksum = crc;
if (lseek64(fd, (sb->data_offset) * 512, 0) < 0LL) {
pr_err("cannot seek to offset of the meta block\n");