/* $OpenBSD: softraid_raid0.c,v 1.53 2020/03/25 21:29:04 tobhe Exp $ */
/*
 * Copyright (c) 2008 Marco Peereboom <marco@peereboom.us>
 *
 * 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/conf.h>
#include <sys/uio.h>

#include <scsi/scsi_all.h>
#include <scsi/scsiconf.h>
#include <scsi/scsi_disk.h>

#include <dev/softraidvar.h>

/* RAID 0 functions. */
int     sr_raid0_create(struct sr_discipline *, struct bioc_createraid *,
            int, int64_t);
int     sr_raid0_assemble(struct sr_discipline *, struct bioc_createraid *,
            int, void *);
int     sr_raid0_init(struct sr_discipline *);
int     sr_raid0_rw(struct sr_workunit *);

/* Discipline initialisation. */
void
sr_raid0_discipline_init(struct sr_discipline *sd)
{

        /* Fill out discipline members. */
        sd->sd_type = SR_MD_RAID0;
        strlcpy(sd->sd_name, "RAID 0", sizeof(sd->sd_name));
        sd->sd_capabilities = SR_CAP_SYSTEM_DISK | SR_CAP_AUTO_ASSEMBLE;
        sd->sd_max_wu = SR_RAID0_NOWU;

        /* Setup discipline specific function pointers. */
        sd->sd_assemble = sr_raid0_assemble;
        sd->sd_create = sr_raid0_create;
        sd->sd_scsi_rw = sr_raid0_rw;
}

int
sr_raid0_create(struct sr_discipline *sd, struct bioc_createraid *bc,
    int no_chunk, int64_t coerced_size)
{
        if (no_chunk < 2) {
                sr_error(sd->sd_sc, "%s requires two 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;

        return sr_raid0_init(sd);
}

int
sr_raid0_assemble(struct sr_discipline *sd, struct bioc_createraid *bc,
    int no_chunks, void *data)
{
        return sr_raid0_init(sd);
}

int
sr_raid0_init(struct sr_discipline *sd)
{
        /* Initialise runtime values. */
        sd->mds.mdd_raid0.sr0_strip_bits =
            sr_validate_stripsize(sd->sd_meta->ssdi.ssd_strip_size);
        if (sd->mds.mdd_raid0.sr0_strip_bits == -1) {
                sr_error(sd->sd_sc, "%s: invalid strip size", sd->sd_name);
                return EINVAL;
        }
        sd->sd_max_ccb_per_wu =
            (MAXPHYS / sd->sd_meta->ssdi.ssd_strip_size + 1) *
            SR_RAID0_NOWU * sd->sd_meta->ssdi.ssd_chunk_no;

        return 0;
}

int
sr_raid0_rw(struct sr_workunit *wu)
{
        struct sr_discipline    *sd = wu->swu_dis;
        struct scsi_xfer        *xs = wu->swu_xs;
        struct sr_ccb           *ccb;
        struct sr_chunk         *scp;
        daddr_t                 blkno;
        int64_t                 chunkoffs, lbaoffs, offset, stripoffs;
        int64_t                 strip_bits, strip_no, strip_size;
        int64_t                 chunk, no_chunk;
        int64_t                 length, leftover;
        u_int8_t                *data;

        /* blkno and scsi error will be handled by sr_validate_io */
        if (sr_validate_io(wu, &blkno, "sr_raid0_rw"))
                goto bad;

        strip_size = sd->sd_meta->ssdi.ssd_strip_size;
        strip_bits = sd->mds.mdd_raid0.sr0_strip_bits;
        no_chunk = sd->sd_meta->ssdi.ssd_chunk_no;

        DNPRINTF(SR_D_DIS, "%s: %s: front end io: blkno %lld size %d\n",
            DEVNAME(sd->sd_sc), sd->sd_meta->ssd_devname,
            (long long)blkno, xs->datalen);

        /* all offs are in bytes */
        lbaoffs = blkno << DEV_BSHIFT;
        strip_no = lbaoffs >> strip_bits;
        chunk = strip_no % no_chunk;
        stripoffs = lbaoffs & (strip_size - 1);
        chunkoffs = (strip_no / no_chunk) << strip_bits;
        offset = chunkoffs + stripoffs;
        length = MIN(xs->datalen, strip_size - stripoffs);
        leftover = xs->datalen;
        data = xs->data;
        for (;;) {
                /* make sure chunk is online */
                scp = sd->sd_vol.sv_chunks[chunk];
                if (scp->src_meta.scm_status != BIOC_SDONLINE)
                        goto bad;

                DNPRINTF(SR_D_DIS, "%s: %s %s io lbaoffs %lld "
                    "strip_no %lld chunk %lld stripoffs %lld "
                    "chunkoffs %lld offset %lld length %lld "
                    "leftover %lld data %p\n",
                    DEVNAME(sd->sd_sc), sd->sd_meta->ssd_devname, sd->sd_name,
                    lbaoffs, strip_no, chunk, stripoffs, chunkoffs, offset,
                    length, leftover, data);

                blkno = offset >> DEV_BSHIFT;
                ccb = sr_ccb_rw(sd, chunk, blkno, length, data, xs->flags, 0);
                if (!ccb) {
                        /* should never happen but handle more gracefully */
                        printf("%s: %s: too many ccbs queued\n",
                            DEVNAME(sd->sd_sc),
                            sd->sd_meta->ssd_devname);
                        goto bad;
                }
                sr_wu_enqueue_ccb(wu, ccb);

                leftover -= length;
                if (leftover == 0)
                        break;

                data += length;
                if (++chunk > no_chunk - 1) {
                        chunk = 0;
                        offset += length;
                } else if (wu->swu_io_count == 1)
                        offset -= stripoffs;
                length = MIN(leftover,strip_size);
        }

        sr_schedule_wu(wu);

        return (0);

bad:
        /* wu is unwound by sr_wu_put */
        return (1);
}