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IABSD.fr/src/sys/dev/softraid_raid6.c
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- sys/dev/softraid_raid6.c
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/* $OpenBSD: softraid_raid6.c,v 1.74 2025/06/13 13:00:49 jsg Exp $ */ /* * Copyright (c) 2009 Marco Peereboom <marco@peereboom.us> * Copyright (c) 2009 Jordan Hargrave <jordan@openbsd.org> * * Permission to use, copy, modify, and distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ #include "bio.h" #include <sys/param.h> #include <sys/systm.h> #include <sys/buf.h> #include <sys/device.h> #include <sys/ioctl.h> #include <sys/malloc.h> #include <sys/kernel.h> #include <sys/disk.h> #include <sys/rwlock.h> #include <sys/queue.h> #include <sys/fcntl.h> #include <sys/mount.h> #include <sys/sensors.h> #include <sys/stat.h> #include <sys/task.h> #include <sys/conf.h> #include <sys/uio.h> #include <scsi/scsi_all.h> #include <scsi/scsiconf.h> #include <scsi/scsi_disk.h> #include <dev/softraidvar.h> uint8_t *gf_map[256]; uint8_t gf_pow[768]; int gf_log[256]; /* RAID 6 functions. */ int sr_raid6_create(struct sr_discipline *, struct bioc_createraid *, int, int64_t); int sr_raid6_assemble(struct sr_discipline *, struct bioc_createraid *, int, void *); int sr_raid6_init(struct sr_discipline *); int sr_raid6_rw(struct sr_workunit *); int sr_raid6_openings(struct sr_discipline *); void sr_raid6_intr(struct buf *); int sr_raid6_wu_done(struct sr_workunit *); void sr_raid6_set_chunk_state(struct sr_discipline *, int, int); void sr_raid6_set_vol_state(struct sr_discipline *); void sr_raid6_xorp(void *, void *, int); void sr_raid6_xorq(void *, void *, int, int); int sr_raid6_addio(struct sr_workunit *wu, int, daddr_t, long, void *, int, int, void *, void *, int); void gf_init(void); uint8_t gf_inv(uint8_t); int gf_premul(uint8_t); uint8_t gf_mul(uint8_t, uint8_t); #define SR_NOFAIL 0x00 #define SR_FAILX (1L << 0) #define SR_FAILY (1L << 1) #define SR_FAILP (1L << 2) #define SR_FAILQ (1L << 3) struct sr_raid6_opaque { int gn; void *pbuf; void *qbuf; }; /* discipline initialisation. */ void sr_raid6_discipline_init(struct sr_discipline *sd) { /* Initialize GF256 tables. */ gf_init(); /* Fill out discipline members. */ sd->sd_type = SR_MD_RAID6; strlcpy(sd->sd_name, "RAID 6", sizeof(sd->sd_name)); sd->sd_capabilities = SR_CAP_SYSTEM_DISK | SR_CAP_AUTO_ASSEMBLE | SR_CAP_REDUNDANT; sd->sd_max_wu = SR_RAID6_NOWU; /* Setup discipline specific function pointers. */ sd->sd_assemble = sr_raid6_assemble; sd->sd_create = sr_raid6_create; sd->sd_openings = sr_raid6_openings; sd->sd_scsi_rw = sr_raid6_rw; sd->sd_scsi_intr = sr_raid6_intr; sd->sd_scsi_wu_done = sr_raid6_wu_done; sd->sd_set_chunk_state = sr_raid6_set_chunk_state; sd->sd_set_vol_state = sr_raid6_set_vol_state; } int sr_raid6_create(struct sr_discipline *sd, struct bioc_createraid *bc, int no_chunk, int64_t coerced_size) { if (no_chunk < 4) { sr_error(sd->sd_sc, "%s requires four or more chunks", sd->sd_name); return EINVAL; } /* * XXX add variable strip size later even though MAXPHYS is really * the clever value, users like * to tinker with that type of stuff. */ sd->sd_meta->ssdi.ssd_strip_size = MAXPHYS; sd->sd_meta->ssdi.ssd_size = (coerced_size & ~(((u_int64_t)sd->sd_meta->ssdi.ssd_strip_size >> DEV_BSHIFT) - 1)) * (no_chunk - 2); return sr_raid6_init(sd); } int sr_raid6_assemble(struct sr_discipline *sd, struct bioc_createraid *bc, int no_chunk, void *data) { return sr_raid6_init(sd); } int sr_raid6_init(struct sr_discipline *sd) { /* Initialise runtime values. */ sd->mds.mdd_raid6.sr6_strip_bits = sr_validate_stripsize(sd->sd_meta->ssdi.ssd_strip_size); if (sd->mds.mdd_raid6.sr6_strip_bits == -1) { sr_error(sd->sd_sc, "invalid strip size"); return EINVAL; } /* only if stripsize <= MAXPHYS */ sd->sd_max_ccb_per_wu = max(6, 2 * sd->sd_meta->ssdi.ssd_chunk_no); return 0; } int sr_raid6_openings(struct sr_discipline *sd) { return (sd->sd_max_wu >> 1); /* 2 wu's per IO */ } void sr_raid6_set_chunk_state(struct sr_discipline *sd, int c, int new_state) { int old_state, s; /* XXX this is for RAID 0 */ DNPRINTF(SR_D_STATE, "%s: %s: %s: sr_raid_set_chunk_state %d -> %d\n", DEVNAME(sd->sd_sc), sd->sd_meta->ssd_devname, sd->sd_vol.sv_chunks[c]->src_meta.scmi.scm_devname, c, new_state); /* ok to go to splbio since this only happens in error path */ s = splbio(); old_state = sd->sd_vol.sv_chunks[c]->src_meta.scm_status; /* multiple IOs to the same chunk that fail will come through here */ if (old_state == new_state) goto done; switch (old_state) { case BIOC_SDONLINE: switch (new_state) { case BIOC_SDOFFLINE: case BIOC_SDSCRUB: break; default: goto die; } break; case BIOC_SDOFFLINE: if (new_state == BIOC_SDREBUILD) { ; } else goto die; break; case BIOC_SDSCRUB: switch (new_state) { case BIOC_SDONLINE: case BIOC_SDOFFLINE: break; default: goto die; } break; case BIOC_SDREBUILD: switch (new_state) { case BIOC_SDONLINE: case BIOC_SDOFFLINE: break; default: goto die; } break; default: die: splx(s); /* XXX */ panic("%s: %s: %s: invalid chunk state transition %d -> %d", DEVNAME(sd->sd_sc), sd->sd_meta->ssd_devname, sd->sd_vol.sv_chunks[c]->src_meta.scmi.scm_devname, old_state, new_state); /* NOTREACHED */ } sd->sd_vol.sv_chunks[c]->src_meta.scm_status = new_state; sd->sd_set_vol_state(sd); sd->sd_must_flush = 1; task_add(systq, &sd->sd_meta_save_task); done: splx(s); } void sr_raid6_set_vol_state(struct sr_discipline *sd) { int states[SR_MAX_STATES]; int new_state, i, s, nd; int old_state = sd->sd_vol_status; /* XXX this is for RAID 0 */ DNPRINTF(SR_D_STATE, "%s: %s: sr_raid_set_vol_state\n", DEVNAME(sd->sd_sc), sd->sd_meta->ssd_devname); nd = sd->sd_meta->ssdi.ssd_chunk_no; for (i = 0; i < SR_MAX_STATES; i++) states[i] = 0; for (i = 0; i < nd; i++) { s = sd->sd_vol.sv_chunks[i]->src_meta.scm_status; if (s >= SR_MAX_STATES) panic("%s: %s: %s: invalid chunk state", DEVNAME(sd->sd_sc), sd->sd_meta->ssd_devname, sd->sd_vol.sv_chunks[i]->src_meta.scmi.scm_devname); states[s]++; } if (states[BIOC_SDONLINE] == nd) new_state = BIOC_SVONLINE; else if (states[BIOC_SDONLINE] < nd - 2) new_state = BIOC_SVOFFLINE; else if (states[BIOC_SDSCRUB] != 0) new_state = BIOC_SVSCRUB; else if (states[BIOC_SDREBUILD] != 0) new_state = BIOC_SVREBUILD; else if (states[BIOC_SDONLINE] < nd) new_state = BIOC_SVDEGRADED; else { printf("old_state = %d, ", old_state); for (i = 0; i < nd; i++) printf("%d = %d, ", i, sd->sd_vol.sv_chunks[i]->src_meta.scm_status); panic("invalid new_state"); } DNPRINTF(SR_D_STATE, "%s: %s: sr_raid_set_vol_state %d -> %d\n", DEVNAME(sd->sd_sc), sd->sd_meta->ssd_devname, old_state, new_state); switch (old_state) { case BIOC_SVONLINE: switch (new_state) { case BIOC_SVONLINE: /* can go to same state */ case BIOC_SVOFFLINE: case BIOC_SVDEGRADED: case BIOC_SVREBUILD: /* happens on boot */ break; default: goto die; } break; case BIOC_SVOFFLINE: /* XXX this might be a little too much */ goto die; case BIOC_SVDEGRADED: switch (new_state) { case BIOC_SVOFFLINE: case BIOC_SVREBUILD: case BIOC_SVDEGRADED: /* can go to the same state */ break; default: goto die; } break; case BIOC_SVBUILDING: switch (new_state) { case BIOC_SVONLINE: case BIOC_SVOFFLINE: case BIOC_SVBUILDING: /* can go to the same state */ break; default: goto die; } break; case BIOC_SVSCRUB: switch (new_state) { case BIOC_SVONLINE: case BIOC_SVOFFLINE: case BIOC_SVDEGRADED: case BIOC_SVSCRUB: /* can go to same state */ break; default: goto die; } break; case BIOC_SVREBUILD: switch (new_state) { case BIOC_SVONLINE: case BIOC_SVOFFLINE: case BIOC_SVDEGRADED: case BIOC_SVREBUILD: /* can go to the same state */ break; default: goto die; } break; default: die: panic("%s: %s: invalid volume state transition %d -> %d", DEVNAME(sd->sd_sc), sd->sd_meta->ssd_devname, old_state, new_state); /* NOTREACHED */ } sd->sd_vol_status = new_state; } /* modes: * readq: sr_raid6_addio(i, lba, length, NULL, SCSI_DATA_IN, * 0, qbuf, NULL, 0); * readp: sr_raid6_addio(i, lba, length, NULL, SCSI_DATA_IN, * 0, pbuf, NULL, 0); * readx: sr_raid6_addio(i, lba, length, NULL, SCSI_DATA_IN, * 0, pbuf, qbuf, gf_pow[i]); */ int sr_raid6_rw(struct sr_workunit *wu) { struct sr_workunit *wu_r = NULL; struct sr_discipline *sd = wu->swu_dis; struct scsi_xfer *xs = wu->swu_xs; struct sr_chunk *scp; int s, fail, i, gxinv, pxinv; daddr_t blkno, lba; int64_t chunk_offs, lbaoffs, offset, strip_offs; int64_t strip_no, strip_size, strip_bits, row_size; int64_t fchunk, no_chunk, chunk, qchunk, pchunk; long length, datalen; void *pbuf, *data, *qbuf; /* blkno and scsi error will be handled by sr_validate_io */ if (sr_validate_io(wu, &blkno, "sr_raid6_rw")) goto bad; strip_size = sd->sd_meta->ssdi.ssd_strip_size; strip_bits = sd->mds.mdd_raid6.sr6_strip_bits; no_chunk = sd->sd_meta->ssdi.ssd_chunk_no - 2; row_size = (no_chunk << strip_bits) >> DEV_BSHIFT; data = xs->data; datalen = xs->datalen; lbaoffs = blkno << DEV_BSHIFT; if (xs->flags & SCSI_DATA_OUT) { if ((wu_r = sr_scsi_wu_get(sd, SCSI_NOSLEEP)) == NULL){ printf("%s: can't get wu_r", DEVNAME(sd->sd_sc)); goto bad; } wu_r->swu_state = SR_WU_INPROGRESS; wu_r->swu_flags |= SR_WUF_DISCIPLINE; } wu->swu_blk_start = 0; while (datalen != 0) { strip_no = lbaoffs >> strip_bits; strip_offs = lbaoffs & (strip_size - 1); chunk_offs = (strip_no / no_chunk) << strip_bits; offset = chunk_offs + strip_offs; /* get size remaining in this stripe */ length = MIN(strip_size - strip_offs, datalen); /* map disk offset to parity/data drive */ chunk = strip_no % no_chunk; qchunk = (no_chunk + 1) - ((strip_no / no_chunk) % (no_chunk+2)); if (qchunk == 0) pchunk = no_chunk + 1; else pchunk = qchunk - 1; if (chunk >= pchunk) chunk++; if (chunk >= qchunk) chunk++; lba = offset >> DEV_BSHIFT; /* XXX big hammer.. exclude I/O from entire stripe */ if (wu->swu_blk_start == 0) wu->swu_blk_start = (strip_no / no_chunk) * row_size; wu->swu_blk_end = (strip_no / no_chunk) * row_size + (row_size - 1); fail = 0; fchunk = -1; /* Get disk-fail flags */ for (i=0; i< no_chunk+2; i++) { scp = sd->sd_vol.sv_chunks[i]; switch (scp->src_meta.scm_status) { case BIOC_SDOFFLINE: case BIOC_SDREBUILD: case BIOC_SDHOTSPARE: if (i == qchunk) fail |= SR_FAILQ; else if (i == pchunk) fail |= SR_FAILP; else if (i == chunk) fail |= SR_FAILX; else { /* dual data-disk failure */ fail |= SR_FAILY; fchunk = i; } break; } } if (xs->flags & SCSI_DATA_IN) { if (!(fail & SR_FAILX)) { /* drive is good. issue single read request */ if (sr_raid6_addio(wu, chunk, lba, length, data, xs->flags, 0, NULL, NULL, 0)) goto bad; } else if (fail & SR_FAILP) { /* Dx, P failed */ printf("Disk %llx offline, " "regenerating Dx+P\n", chunk); gxinv = gf_inv(gf_pow[chunk]); /* Calculate: Dx = (Q^Dz*gz)*inv(gx) */ memset(data, 0, length); if (sr_raid6_addio(wu, qchunk, lba, length, NULL, SCSI_DATA_IN, 0, NULL, data, gxinv)) goto bad; /* Read Dz * gz * inv(gx) */ for (i = 0; i < no_chunk+2; i++) { if (i == qchunk || i == pchunk || i == chunk) continue; if (sr_raid6_addio(wu, i, lba, length, NULL, SCSI_DATA_IN, 0, NULL, data, gf_mul(gf_pow[i], gxinv))) goto bad; } /* data will contain correct value on completion */ } else if (fail & SR_FAILY) { /* Dx, Dy failed */ printf("Disk %llx & %llx offline, " "regenerating Dx+Dy\n", chunk, fchunk); gxinv = gf_inv(gf_pow[chunk] ^ gf_pow[fchunk]); pxinv = gf_mul(gf_pow[fchunk], gxinv); /* read Q * inv(gx + gy) */ memset(data, 0, length); if (sr_raid6_addio(wu, qchunk, lba, length, NULL, SCSI_DATA_IN, 0, NULL, data, gxinv)) goto bad; /* read P * gy * inv(gx + gy) */ if (sr_raid6_addio(wu, pchunk, lba, length, NULL, SCSI_DATA_IN, 0, NULL, data, pxinv)) goto bad; /* Calculate: Dx*gx^Dy*gy = Q^(Dz*gz) ; Dx^Dy = P^Dz * Q: sr_raid6_xorp(qbuf, --, length); * P: sr_raid6_xorp(pbuf, --, length); * Dz: sr_raid6_xorp(pbuf, --, length); * sr_raid6_xorq(qbuf, --, length, gf_pow[i]); */ for (i = 0; i < no_chunk+2; i++) { if (i == qchunk || i == pchunk || i == chunk || i == fchunk) continue; /* read Dz * (gz + gy) * inv(gx + gy) */ if (sr_raid6_addio(wu, i, lba, length, NULL, SCSI_DATA_IN, 0, NULL, data, pxinv ^ gf_mul(gf_pow[i], gxinv))) goto bad; } } else { /* Two cases: single disk (Dx) or (Dx+Q) * Dx = Dz ^ P (same as RAID5) */ printf("Disk %llx offline, " "regenerating Dx%s\n", chunk, fail & SR_FAILQ ? "+Q" : " single"); /* Calculate: Dx = P^Dz * P: sr_raid6_xorp(data, ---, length); * Dz: sr_raid6_xorp(data, ---, length); */ memset(data, 0, length); for (i = 0; i < no_chunk+2; i++) { if (i != chunk && i != qchunk) { /* Read Dz */ if (sr_raid6_addio(wu, i, lba, length, NULL, SCSI_DATA_IN, 0, data, NULL, 0)) goto bad; } } /* data will contain correct value on completion */ } } else { /* XXX handle writes to failed/offline disk? */ if (fail & (SR_FAILX|SR_FAILQ|SR_FAILP)) goto bad; /* * initialize pbuf with contents of new data to be * written. This will be XORed with old data and old * parity in the intr routine. The result in pbuf * is the new parity data. */ qbuf = sr_block_get(sd, length); if (qbuf == NULL) goto bad; pbuf = sr_block_get(sd, length); if (pbuf == NULL) goto bad; /* Calculate P = Dn; Q = gn * Dn */ if (gf_premul(gf_pow[chunk])) goto bad; sr_raid6_xorp(pbuf, data, length); sr_raid6_xorq(qbuf, data, length, gf_pow[chunk]); /* Read old data: P ^= Dn' ; Q ^= (gn * Dn') */ if (sr_raid6_addio(wu_r, chunk, lba, length, NULL, SCSI_DATA_IN, 0, pbuf, qbuf, gf_pow[chunk])) goto bad; /* Read old xor-parity: P ^= P' */ if (sr_raid6_addio(wu_r, pchunk, lba, length, NULL, SCSI_DATA_IN, 0, pbuf, NULL, 0)) goto bad; /* Read old q-parity: Q ^= Q' */ if (sr_raid6_addio(wu_r, qchunk, lba, length, NULL, SCSI_DATA_IN, 0, qbuf, NULL, 0)) goto bad; /* write new data */ if (sr_raid6_addio(wu, chunk, lba, length, data, xs->flags, 0, NULL, NULL, 0)) goto bad; /* write new xor-parity */ if (sr_raid6_addio(wu, pchunk, lba, length, pbuf, xs->flags, SR_CCBF_FREEBUF, NULL, NULL, 0)) goto bad; /* write new q-parity */ if (sr_raid6_addio(wu, qchunk, lba, length, qbuf, xs->flags, SR_CCBF_FREEBUF, NULL, NULL, 0)) goto bad; } /* advance to next block */ lbaoffs += length; datalen -= length; data += length; } s = splbio(); if (wu_r) { /* collide write request with reads */ wu_r->swu_blk_start = wu->swu_blk_start; wu_r->swu_blk_end = wu->swu_blk_end; wu->swu_state = SR_WU_DEFERRED; wu_r->swu_collider = wu; TAILQ_INSERT_TAIL(&sd->sd_wu_defq, wu, swu_link); wu = wu_r; } splx(s); sr_schedule_wu(wu); return (0); bad: /* XXX - can leak pbuf/qbuf on error. */ /* wu is unwound by sr_wu_put */ if (wu_r) sr_scsi_wu_put(sd, wu_r); return (1); } void sr_raid6_intr(struct buf *bp) { struct sr_ccb *ccb = (struct sr_ccb *)bp; struct sr_workunit *wu = ccb->ccb_wu; struct sr_discipline *sd = wu->swu_dis; struct sr_raid6_opaque *pq = ccb->ccb_opaque; int s; DNPRINTF(SR_D_INTR, "%s: sr_raid6_intr bp %p xs %p\n", DEVNAME(sd->sd_sc), bp, wu->swu_xs); s = splbio(); sr_ccb_done(ccb); /* XOR data to result. */ if (ccb->ccb_state == SR_CCB_OK && pq) { if (pq->pbuf) /* Calculate xor-parity */ sr_raid6_xorp(pq->pbuf, ccb->ccb_buf.b_data, ccb->ccb_buf.b_bcount); if (pq->qbuf) /* Calculate q-parity */ sr_raid6_xorq(pq->qbuf, ccb->ccb_buf.b_data, ccb->ccb_buf.b_bcount, pq->gn); free(pq, M_DEVBUF, 0); ccb->ccb_opaque = NULL; } /* Free allocated data buffer. */ if (ccb->ccb_flags & SR_CCBF_FREEBUF) { sr_block_put(sd, ccb->ccb_buf.b_data, ccb->ccb_buf.b_bcount); ccb->ccb_buf.b_data = NULL; } sr_wu_done(wu); splx(s); } int sr_raid6_wu_done(struct sr_workunit *wu) { struct sr_discipline *sd = wu->swu_dis; struct scsi_xfer *xs = wu->swu_xs; /* XXX - we have no way of propagating errors... */ if (wu->swu_flags & SR_WUF_DISCIPLINE) return SR_WU_OK; /* XXX - This is insufficient for RAID 6. */ if (wu->swu_ios_succeeded > 0) { xs->error = XS_NOERROR; return SR_WU_OK; } if (xs->flags & SCSI_DATA_IN) { printf("%s: retrying read on block %lld\n", sd->sd_meta->ssd_devname, (long long)wu->swu_blk_start); sr_wu_release_ccbs(wu); wu->swu_state = SR_WU_RESTART; if (sd->sd_scsi_rw(wu) == 0) return SR_WU_RESTART; } else { printf("%s: permanently fail write on block %lld\n", sd->sd_meta->ssd_devname, (long long)wu->swu_blk_start); } wu->swu_state = SR_WU_FAILED; xs->error = XS_DRIVER_STUFFUP; return SR_WU_FAILED; } int sr_raid6_addio(struct sr_workunit *wu, int chunk, daddr_t blkno, long len, void *data, int xsflags, int ccbflags, void *pbuf, void *qbuf, int gn) { struct sr_discipline *sd = wu->swu_dis; struct sr_ccb *ccb; struct sr_raid6_opaque *pqbuf; DNPRINTF(SR_D_DIS, "sr_raid6_addio: %s %d.%lld %ld %p:%p\n", (xsflags & SCSI_DATA_IN) ? "read" : "write", chunk, (long long)blkno, len, pbuf, qbuf); /* Allocate temporary buffer. */ if (data == NULL) { data = sr_block_get(sd, len); if (data == NULL) return (-1); ccbflags |= SR_CCBF_FREEBUF; } ccb = sr_ccb_rw(sd, chunk, blkno, len, data, xsflags, ccbflags); if (ccb == NULL) { if (ccbflags & SR_CCBF_FREEBUF) sr_block_put(sd, data, len); return (-1); } if (pbuf || qbuf) { /* XXX - can leak data and ccb on failure. */ if (qbuf && gf_premul(gn)) return (-1); /* XXX - should be preallocated? */ pqbuf = malloc(sizeof(struct sr_raid6_opaque), M_DEVBUF, M_ZERO | M_NOWAIT); if (pqbuf == NULL) { sr_ccb_put(ccb); return (-1); } pqbuf->pbuf = pbuf; pqbuf->qbuf = qbuf; pqbuf->gn = gn; ccb->ccb_opaque = pqbuf; } sr_wu_enqueue_ccb(wu, ccb); return (0); } /* Perform RAID6 parity calculation. * P=xor parity, Q=GF256 parity, D=data, gn=disk# */ void sr_raid6_xorp(void *p, void *d, int len) { uint32_t *pbuf = p, *data = d; len >>= 2; while (len--) *pbuf++ ^= *data++; } void sr_raid6_xorq(void *q, void *d, int len, int gn) { uint32_t *qbuf = q, *data = d, x; uint8_t *gn_map = gf_map[gn]; len >>= 2; while (len--) { x = *data++; *qbuf++ ^= (((uint32_t)gn_map[x & 0xff]) | ((uint32_t)gn_map[(x >> 8) & 0xff] << 8) | ((uint32_t)gn_map[(x >> 16) & 0xff] << 16) | ((uint32_t)gn_map[(x >> 24) & 0xff] << 24)); } } /* Create GF256 log/pow tables: polynomial = 0x11D */ void gf_init(void) { int i; uint8_t p = 1; /* use 2N pow table to avoid using % in multiply */ for (i=0; i<256; i++) { gf_log[p] = i; gf_pow[i] = gf_pow[i+255] = p; p = ((p << 1) ^ ((p & 0x80) ? 0x1D : 0x00)); } gf_log[0] = 512; } uint8_t gf_inv(uint8_t a) { return gf_pow[255 - gf_log[a]]; } uint8_t gf_mul(uint8_t a, uint8_t b) { return gf_pow[gf_log[a] + gf_log[b]]; } /* Precalculate multiplication tables for drive gn */ int gf_premul(uint8_t gn) { int i; if (gf_map[gn] != NULL) return (0); if ((gf_map[gn] = malloc(256, M_DEVBUF, M_ZERO | M_NOWAIT)) == NULL) return (-1); for (i=0; i<256; i++) gf_map[gn][i] = gf_pow[gf_log[i] + gf_log[gn]]; return (0); }