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Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation inc 53 temple place ste 330 boston ma 02111 1307 usa either version 2 of the license or at your option any later version incorporated herein by reference extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 13 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190520170858.645641371@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
137 lines
3.3 KiB
C
137 lines
3.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* -*- linux-c -*- ------------------------------------------------------- *
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*
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* Copyright 2002 H. Peter Anvin - All Rights Reserved
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*
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* ----------------------------------------------------------------------- */
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/*
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* raid6/recov.c
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*
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* RAID-6 data recovery in dual failure mode. In single failure mode,
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* use the RAID-5 algorithm (or, in the case of Q failure, just reconstruct
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* the syndrome.)
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*/
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#include <linux/export.h>
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#include <linux/raid/pq.h>
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/* Recover two failed data blocks. */
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static void raid6_2data_recov_intx1(int disks, size_t bytes, int faila,
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int failb, void **ptrs)
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{
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u8 *p, *q, *dp, *dq;
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u8 px, qx, db;
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const u8 *pbmul; /* P multiplier table for B data */
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const u8 *qmul; /* Q multiplier table (for both) */
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p = (u8 *)ptrs[disks-2];
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q = (u8 *)ptrs[disks-1];
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/* Compute syndrome with zero for the missing data pages
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Use the dead data pages as temporary storage for
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delta p and delta q */
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dp = (u8 *)ptrs[faila];
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ptrs[faila] = (void *)raid6_empty_zero_page;
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ptrs[disks-2] = dp;
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dq = (u8 *)ptrs[failb];
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ptrs[failb] = (void *)raid6_empty_zero_page;
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ptrs[disks-1] = dq;
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raid6_call.gen_syndrome(disks, bytes, ptrs);
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/* Restore pointer table */
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ptrs[faila] = dp;
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ptrs[failb] = dq;
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ptrs[disks-2] = p;
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ptrs[disks-1] = q;
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/* Now, pick the proper data tables */
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pbmul = raid6_gfmul[raid6_gfexi[failb-faila]];
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qmul = raid6_gfmul[raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]]];
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/* Now do it... */
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while ( bytes-- ) {
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px = *p ^ *dp;
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qx = qmul[*q ^ *dq];
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*dq++ = db = pbmul[px] ^ qx; /* Reconstructed B */
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*dp++ = db ^ px; /* Reconstructed A */
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p++; q++;
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}
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}
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/* Recover failure of one data block plus the P block */
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static void raid6_datap_recov_intx1(int disks, size_t bytes, int faila,
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void **ptrs)
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{
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u8 *p, *q, *dq;
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const u8 *qmul; /* Q multiplier table */
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p = (u8 *)ptrs[disks-2];
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q = (u8 *)ptrs[disks-1];
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/* Compute syndrome with zero for the missing data page
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Use the dead data page as temporary storage for delta q */
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dq = (u8 *)ptrs[faila];
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ptrs[faila] = (void *)raid6_empty_zero_page;
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ptrs[disks-1] = dq;
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raid6_call.gen_syndrome(disks, bytes, ptrs);
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/* Restore pointer table */
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ptrs[faila] = dq;
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ptrs[disks-1] = q;
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/* Now, pick the proper data tables */
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qmul = raid6_gfmul[raid6_gfinv[raid6_gfexp[faila]]];
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/* Now do it... */
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while ( bytes-- ) {
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*p++ ^= *dq = qmul[*q ^ *dq];
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q++; dq++;
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}
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}
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const struct raid6_recov_calls raid6_recov_intx1 = {
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.data2 = raid6_2data_recov_intx1,
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.datap = raid6_datap_recov_intx1,
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.valid = NULL,
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.name = "intx1",
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.priority = 0,
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};
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#ifndef __KERNEL__
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/* Testing only */
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/* Recover two failed blocks. */
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void raid6_dual_recov(int disks, size_t bytes, int faila, int failb, void **ptrs)
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{
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if ( faila > failb ) {
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int tmp = faila;
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faila = failb;
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failb = tmp;
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}
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if ( failb == disks-1 ) {
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if ( faila == disks-2 ) {
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/* P+Q failure. Just rebuild the syndrome. */
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raid6_call.gen_syndrome(disks, bytes, ptrs);
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} else {
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/* data+Q failure. Reconstruct data from P,
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then rebuild syndrome. */
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/* NOT IMPLEMENTED - equivalent to RAID-5 */
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}
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} else {
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if ( failb == disks-2 ) {
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/* data+P failure. */
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raid6_datap_recov(disks, bytes, faila, ptrs);
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} else {
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/* data+data failure. */
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raid6_2data_recov(disks, bytes, faila, failb, ptrs);
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}
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}
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}
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#endif
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