173 lines
4.3 KiB
C
173 lines
4.3 KiB
C
/* -*- linux-c -*- ------------------------------------------------------- *
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*
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* Copyright 2002-2004 H. Peter Anvin - All Rights Reserved
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, Inc., 53 Temple Place Ste 330,
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* Boston MA 02111-1307, USA; either version 2 of the License, or
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* (at your option) any later version; incorporated herein by reference.
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*
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* ----------------------------------------------------------------------- */
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/*
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* Added helpers for unaligned native int access
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*/
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/*
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* raid6int1.c
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*
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* 1-way unrolled portable integer math RAID-6 instruction set
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*
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* This file was postprocessed using unroll.pl and then ported to userspace
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*/
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#include <stdint.h>
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#include <unistd.h>
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#include "kerncompat.h"
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#include "ctree.h"
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#include "disk-io.h"
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#include "volumes.h"
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#include "utils.h"
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/*
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* This is the C data type to use
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*/
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/* Change this from BITS_PER_LONG if there is something better... */
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#if BITS_PER_LONG == 64
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# define NBYTES(x) ((x) * 0x0101010101010101UL)
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# define NSIZE 8
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# define NSHIFT 3
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typedef uint64_t unative_t;
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#define put_unaligned_native(val,p) put_unaligned_64((val),(p))
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#define get_unaligned_native(p) get_unaligned_64((p))
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#else
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# define NBYTES(x) ((x) * 0x01010101U)
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# define NSIZE 4
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# define NSHIFT 2
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typedef uint32_t unative_t;
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#define put_unaligned_native(val,p) put_unaligned_32((val),(p))
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#define get_unaligned_native(p) get_unaligned_32((p))
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#endif
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/*
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* These sub-operations are separate inlines since they can sometimes be
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* specially optimized using architecture-specific hacks.
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*/
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/*
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* The SHLBYTE() operation shifts each byte left by 1, *not*
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* rolling over into the next byte
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*/
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static inline __attribute_const__ unative_t SHLBYTE(unative_t v)
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{
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unative_t vv;
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vv = (v << 1) & NBYTES(0xfe);
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return vv;
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}
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/*
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* The MASK() operation returns 0xFF in any byte for which the high
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* bit is 1, 0x00 for any byte for which the high bit is 0.
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*/
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static inline __attribute_const__ unative_t MASK(unative_t v)
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{
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unative_t vv;
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vv = v & NBYTES(0x80);
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vv = (vv << 1) - (vv >> 7); /* Overflow on the top bit is OK */
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return vv;
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}
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void raid6_gen_syndrome(int disks, size_t bytes, void **ptrs)
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{
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uint8_t **dptr = (uint8_t **)ptrs;
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uint8_t *p, *q;
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int d, z, z0;
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unative_t wd0, wq0, wp0, w10, w20;
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z0 = disks - 3; /* Highest data disk */
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p = dptr[z0+1]; /* XOR parity */
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q = dptr[z0+2]; /* RS syndrome */
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for ( d = 0 ; d < bytes ; d += NSIZE*1 ) {
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wq0 = wp0 = get_unaligned_native(&dptr[z0][d+0*NSIZE]);
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for ( z = z0-1 ; z >= 0 ; z-- ) {
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wd0 = get_unaligned_native(&dptr[z][d+0*NSIZE]);
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wp0 ^= wd0;
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w20 = MASK(wq0);
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w10 = SHLBYTE(wq0);
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w20 &= NBYTES(0x1d);
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w10 ^= w20;
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wq0 = w10 ^ wd0;
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}
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put_unaligned_native(wp0, &p[d+NSIZE*0]);
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put_unaligned_native(wq0, &q[d+NSIZE*0]);
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}
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}
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static void xor_range(char *dst, const char*src, size_t size)
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{
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/* Move to DWORD aligned */
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while (size && ((unsigned long)dst & sizeof(unsigned long))) {
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*dst++ ^= *src++;
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size--;
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}
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/* DWORD aligned part */
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while (size >= sizeof(unsigned long)) {
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*(unsigned long *)dst ^= *(unsigned long *)src;
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src += sizeof(unsigned long);
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dst += sizeof(unsigned long);
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size -= sizeof(unsigned long);
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}
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/* Remaining */
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while (size) {
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*dst++ ^= *src++;
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size--;
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}
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}
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/*
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* Generate desired data/parity stripe for RAID5
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*
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* @nr_devs: Total number of devices, including parity
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* @stripe_len: Stripe length
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* @data: Data, with special layout:
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* data[0]: Data stripe 0
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* data[nr_devs-2]: Last data stripe
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* data[nr_devs-1]: RAID5 parity
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* @dest: To generate which data. should follow above data layout
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*/
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int raid5_gen_result(int nr_devs, size_t stripe_len, int dest, void **data)
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{
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int i;
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char *buf = data[dest];
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/* Validation check */
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if (stripe_len <= 0 || stripe_len != BTRFS_STRIPE_LEN) {
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error("invalid parameter for %s", __func__);
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return -EINVAL;
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}
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if (dest >= nr_devs || nr_devs < 2) {
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error("invalid parameter for %s", __func__);
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return -EINVAL;
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}
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/* Shortcut for 2 devs RAID5, which is just RAID1 */
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if (nr_devs == 2) {
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memcpy(data[dest], data[1 - dest], stripe_len);
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return 0;
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}
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memset(buf, 0, stripe_len);
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for (i = 0; i < nr_devs; i++) {
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if (i == dest)
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continue;
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xor_range(buf, data[i], stripe_len);
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}
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return 0;
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}
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