GUI: Fix Tomato RAF theme for all builds. Compilation typo.

[tomato.git] / release / src-rt-6.x.4708 / linux / linux-2.6.36 / drivers / scsi / device_handler / scsi_dh_rdac.c

/*
 * Engenio/LSI RDAC SCSI Device Handler
 *
 * Copyright (C) 2005 Mike Christie. All rights reserved.
 * Copyright (C) Chandra Seetharaman, IBM Corp. 2007
 *
 * 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; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 */
#include <scsi/scsi.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_dh.h>
#include <linux/workqueue.h>
#include <linux/slab.h>

#define RDAC_NAME "rdac"
#define RDAC_RETRY_COUNT 5

/*
 * LSI mode page stuff
 *
 * These struct definitions and the forming of the
 * mode page were taken from the LSI RDAC 2.4 GPL'd
 * driver, and then converted to Linux conventions.
 */
#define RDAC_QUIESCENCE_TIME 20;
/*
 * Page Codes
 */
#define RDAC_PAGE_CODE_REDUNDANT_CONTROLLER 0x2c

/*
 * Controller modes definitions
 */
#define RDAC_MODE_TRANSFER_SPECIFIED_LUNS       0x02

/*
 * RDAC Options field
 */
#define RDAC_FORCED_QUIESENCE 0x02

#define RDAC_TIMEOUT    (60 * HZ)
#define RDAC_RETRIES    3

struct rdac_mode_6_hdr {
        u8      data_len;
        u8      medium_type;
        u8      device_params;
        u8      block_desc_len;
};

struct rdac_mode_10_hdr {
        u16     data_len;
        u8      medium_type;
        u8      device_params;
        u16     reserved;
        u16     block_desc_len;
};

struct rdac_mode_common {
        u8      controller_serial[16];
        u8      alt_controller_serial[16];
        u8      rdac_mode[2];
        u8      alt_rdac_mode[2];
        u8      quiescence_timeout;
        u8      rdac_options;
};

struct rdac_pg_legacy {
        struct rdac_mode_6_hdr hdr;
        u8      page_code;
        u8      page_len;
        struct rdac_mode_common common;
#define MODE6_MAX_LUN   32
        u8      lun_table[MODE6_MAX_LUN];
        u8      reserved2[32];
        u8      reserved3;
        u8      reserved4;
};

struct rdac_pg_expanded {
        struct rdac_mode_10_hdr hdr;
        u8      page_code;
        u8      subpage_code;
        u8      page_len[2];
        struct rdac_mode_common common;
        u8      lun_table[256];
        u8      reserved3;
        u8      reserved4;
};

struct c9_inquiry {
        u8      peripheral_info;
        u8      page_code;      /* 0xC9 */
        u8      reserved1;
        u8      page_len;
        u8      page_id[4];     /* "vace" */
        u8      avte_cvp;
        u8      path_prio;
        u8      reserved2[38];
};

#define SUBSYS_ID_LEN   16
#define SLOT_ID_LEN     2
#define ARRAY_LABEL_LEN 31

struct c4_inquiry {
        u8      peripheral_info;
        u8      page_code;      /* 0xC4 */
        u8      reserved1;
        u8      page_len;
        u8      page_id[4];     /* "subs" */
        u8      subsys_id[SUBSYS_ID_LEN];
        u8      revision[4];
        u8      slot_id[SLOT_ID_LEN];
        u8      reserved[2];
};

struct rdac_controller {
        u8                      subsys_id[SUBSYS_ID_LEN];
        u8                      slot_id[SLOT_ID_LEN];
        int                     use_ms10;
        struct kref             kref;
        struct list_head        node; /* list of all controllers */
        union                   {
                struct rdac_pg_legacy legacy;
                struct rdac_pg_expanded expanded;
        } mode_select;
        u8      index;
        u8      array_name[ARRAY_LABEL_LEN];
        spinlock_t              ms_lock;
        int                     ms_queued;
        struct work_struct      ms_work;
        struct scsi_device      *ms_sdev;
        struct list_head        ms_head;
};

struct c8_inquiry {
        u8      peripheral_info;
        u8      page_code; /* 0xC8 */
        u8      reserved1;
        u8      page_len;
        u8      page_id[4]; /* "edid" */
        u8      reserved2[3];
        u8      vol_uniq_id_len;
        u8      vol_uniq_id[16];
        u8      vol_user_label_len;
        u8      vol_user_label[60];
        u8      array_uniq_id_len;
        u8      array_unique_id[16];
        u8      array_user_label_len;
        u8      array_user_label[60];
        u8      lun[8];
};

struct c2_inquiry {
        u8      peripheral_info;
        u8      page_code;      /* 0xC2 */
        u8      reserved1;
        u8      page_len;
        u8      page_id[4];     /* "swr4" */
        u8      sw_version[3];
        u8      sw_date[3];
        u8      features_enabled;
        u8      max_lun_supported;
        u8      partitions[239]; /* Total allocation length should be 0xFF */
};

struct rdac_dh_data {
        struct rdac_controller  *ctlr;
#define UNINITIALIZED_LUN       (1 << 8)
        unsigned                lun;
#define RDAC_STATE_ACTIVE       0
#define RDAC_STATE_PASSIVE      1
        unsigned char           state;

#define RDAC_LUN_UNOWNED        0
#define RDAC_LUN_OWNED          1
#define RDAC_LUN_AVT            2
        char                    lun_state;
        unsigned char           sense[SCSI_SENSE_BUFFERSIZE];
        union                   {
                struct c2_inquiry c2;
                struct c4_inquiry c4;
                struct c8_inquiry c8;
                struct c9_inquiry c9;
        } inq;
};

static const char *lun_state[] =
{
        "unowned",
        "owned",
        "owned (AVT mode)",
};

struct rdac_queue_data {
        struct list_head        entry;
        struct rdac_dh_data     *h;
        activate_complete       callback_fn;
        void                    *callback_data;
};

static LIST_HEAD(ctlr_list);
static DEFINE_SPINLOCK(list_lock);
static struct workqueue_struct *kmpath_rdacd;
static void send_mode_select(struct work_struct *work);

/*
 * module parameter to enable rdac debug logging.
 * 2 bits for each type of logging, only two types defined for now
 * Can be enhanced if required at later point
 */
static int rdac_logging = 1;
module_param(rdac_logging, int, S_IRUGO|S_IWUSR);
MODULE_PARM_DESC(rdac_logging, "A bit mask of rdac logging levels, "
                "Default is 1 - failover logging enabled, "
                "set it to 0xF to enable all the logs");

#define RDAC_LOG_FAILOVER       0
#define RDAC_LOG_SENSE          2

#define RDAC_LOG_BITS           2

#define RDAC_LOG_LEVEL(SHIFT)  \
        ((rdac_logging >> (SHIFT)) & ((1 << (RDAC_LOG_BITS)) - 1))

#define RDAC_LOG(SHIFT, sdev, f, arg...) \
do { \
        if (unlikely(RDAC_LOG_LEVEL(SHIFT))) \
                sdev_printk(KERN_INFO, sdev, RDAC_NAME ": " f "\n", ## arg); \
} while (0);

static inline struct rdac_dh_data *get_rdac_data(struct scsi_device *sdev)
{
        struct scsi_dh_data *scsi_dh_data = sdev->scsi_dh_data;
        BUG_ON(scsi_dh_data == NULL);
        return ((struct rdac_dh_data *) scsi_dh_data->buf);
}

static struct request *get_rdac_req(struct scsi_device *sdev,
                        void *buffer, unsigned buflen, int rw)
{
        struct request *rq;
        struct request_queue *q = sdev->request_queue;

        rq = blk_get_request(q, rw, GFP_NOIO);

        if (!rq) {
                sdev_printk(KERN_INFO, sdev,
                                "get_rdac_req: blk_get_request failed.\n");
                return NULL;
        }

        if (buflen && blk_rq_map_kern(q, rq, buffer, buflen, GFP_NOIO)) {
                blk_put_request(rq);
                sdev_printk(KERN_INFO, sdev,
                                "get_rdac_req: blk_rq_map_kern failed.\n");
                return NULL;
        }

        rq->cmd_type = REQ_TYPE_BLOCK_PC;
        rq->cmd_flags |= REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
                         REQ_FAILFAST_DRIVER;
        rq->retries = RDAC_RETRIES;
        rq->timeout = RDAC_TIMEOUT;

        return rq;
}

static struct request *rdac_failover_get(struct scsi_device *sdev,
                                         struct rdac_dh_data *h)
{
        struct request *rq;
        struct rdac_mode_common *common;
        unsigned data_size;

        if (h->ctlr->use_ms10) {
                struct rdac_pg_expanded *rdac_pg;

                data_size = sizeof(struct rdac_pg_expanded);
                rdac_pg = &h->ctlr->mode_select.expanded;
                memset(rdac_pg, 0, data_size);
                common = &rdac_pg->common;
                rdac_pg->page_code = RDAC_PAGE_CODE_REDUNDANT_CONTROLLER + 0x40;
                rdac_pg->subpage_code = 0x1;
                rdac_pg->page_len[0] = 0x01;
                rdac_pg->page_len[1] = 0x28;
        } else {
                struct rdac_pg_legacy *rdac_pg;

                data_size = sizeof(struct rdac_pg_legacy);
                rdac_pg = &h->ctlr->mode_select.legacy;
                memset(rdac_pg, 0, data_size);
                common = &rdac_pg->common;
                rdac_pg->page_code = RDAC_PAGE_CODE_REDUNDANT_CONTROLLER;
                rdac_pg->page_len = 0x68;
        }
        common->rdac_mode[1] = RDAC_MODE_TRANSFER_SPECIFIED_LUNS;
        common->quiescence_timeout = RDAC_QUIESCENCE_TIME;
        common->rdac_options = RDAC_FORCED_QUIESENCE;

        /* get request for block layer packet command */
        rq = get_rdac_req(sdev, &h->ctlr->mode_select, data_size, WRITE);
        if (!rq)
                return NULL;

        /* Prepare the command. */
        if (h->ctlr->use_ms10) {
                rq->cmd[0] = MODE_SELECT_10;
                rq->cmd[7] = data_size >> 8;
                rq->cmd[8] = data_size & 0xff;
        } else {
                rq->cmd[0] = MODE_SELECT;
                rq->cmd[4] = data_size;
        }
        rq->cmd_len = COMMAND_SIZE(rq->cmd[0]);

        rq->sense = h->sense;
        memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
        rq->sense_len = 0;

        return rq;
}

static void release_controller(struct kref *kref)
{
        struct rdac_controller *ctlr;
        ctlr = container_of(kref, struct rdac_controller, kref);

        flush_workqueue(kmpath_rdacd);
        spin_lock(&list_lock);
        list_del(&ctlr->node);
        spin_unlock(&list_lock);
        kfree(ctlr);
}

static struct rdac_controller *get_controller(u8 *subsys_id, u8 *slot_id,
                                                char *array_name)
{
        struct rdac_controller *ctlr, *tmp;

        spin_lock(&list_lock);

        list_for_each_entry(tmp, &ctlr_list, node) {
                if ((memcmp(tmp->subsys_id, subsys_id, SUBSYS_ID_LEN) == 0) &&
                          (memcmp(tmp->slot_id, slot_id, SLOT_ID_LEN) == 0)) {
                        kref_get(&tmp->kref);
                        spin_unlock(&list_lock);
                        return tmp;
                }
        }
        ctlr = kmalloc(sizeof(*ctlr), GFP_ATOMIC);
        if (!ctlr)
                goto done;

        /* initialize fields of controller */
        memcpy(ctlr->subsys_id, subsys_id, SUBSYS_ID_LEN);
        memcpy(ctlr->slot_id, slot_id, SLOT_ID_LEN);
        memcpy(ctlr->array_name, array_name, ARRAY_LABEL_LEN);

        /* update the controller index */
        if (slot_id[1] == 0x31)
                ctlr->index = 0;
        else
                ctlr->index = 1;

        kref_init(&ctlr->kref);
        ctlr->use_ms10 = -1;
        ctlr->ms_queued = 0;
        ctlr->ms_sdev = NULL;
        spin_lock_init(&ctlr->ms_lock);
        INIT_WORK(&ctlr->ms_work, send_mode_select);
        INIT_LIST_HEAD(&ctlr->ms_head);
        list_add(&ctlr->node, &ctlr_list);
done:
        spin_unlock(&list_lock);
        return ctlr;
}

static int submit_inquiry(struct scsi_device *sdev, int page_code,
                          unsigned int len, struct rdac_dh_data *h)
{
        struct request *rq;
        struct request_queue *q = sdev->request_queue;
        int err = SCSI_DH_RES_TEMP_UNAVAIL;

        rq = get_rdac_req(sdev, &h->inq, len, READ);
        if (!rq)
                goto done;

        /* Prepare the command. */
        rq->cmd[0] = INQUIRY;
        rq->cmd[1] = 1;
        rq->cmd[2] = page_code;
        rq->cmd[4] = len;
        rq->cmd_len = COMMAND_SIZE(INQUIRY);

        rq->sense = h->sense;
        memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
        rq->sense_len = 0;

        err = blk_execute_rq(q, NULL, rq, 1);
        if (err == -EIO)
                err = SCSI_DH_IO;

        blk_put_request(rq);
done:
        return err;
}

static int get_lun_info(struct scsi_device *sdev, struct rdac_dh_data *h,
                        char *array_name)
{
        int err, i;
        struct c8_inquiry *inqp;

        err = submit_inquiry(sdev, 0xC8, sizeof(struct c8_inquiry), h);
        if (err == SCSI_DH_OK) {
                inqp = &h->inq.c8;
                if (inqp->page_code != 0xc8)
                        return SCSI_DH_NOSYS;
                if (inqp->page_id[0] != 'e' || inqp->page_id[1] != 'd' ||
                    inqp->page_id[2] != 'i' || inqp->page_id[3] != 'd')
                        return SCSI_DH_NOSYS;
                h->lun = inqp->lun[7]; /* Uses only the last byte */

                for(i=0; i<ARRAY_LABEL_LEN-1; ++i)
                        *(array_name+i) = inqp->array_user_label[(2*i)+1];

                *(array_name+ARRAY_LABEL_LEN-1) = '\0';
        }
        return err;
}

static int check_ownership(struct scsi_device *sdev, struct rdac_dh_data *h)
{
        int err;
        struct c9_inquiry *inqp;

        h->lun_state = RDAC_LUN_UNOWNED;
        h->state = RDAC_STATE_ACTIVE;
        err = submit_inquiry(sdev, 0xC9, sizeof(struct c9_inquiry), h);
        if (err == SCSI_DH_OK) {
                inqp = &h->inq.c9;
                if ((inqp->avte_cvp >> 7) == 0x1) {
                        /* LUN in AVT mode */
                        sdev_printk(KERN_NOTICE, sdev,
                                    "%s: AVT mode detected\n",
                                    RDAC_NAME);
                        h->lun_state = RDAC_LUN_AVT;
                } else if ((inqp->avte_cvp & 0x1) != 0) {
                        /* LUN was owned by the controller */
                        h->lun_state = RDAC_LUN_OWNED;
                }
        }

        if (h->lun_state == RDAC_LUN_UNOWNED)
                h->state = RDAC_STATE_PASSIVE;

        return err;
}

static int initialize_controller(struct scsi_device *sdev,
                                 struct rdac_dh_data *h, char *array_name)
{
        int err;
        struct c4_inquiry *inqp;

        err = submit_inquiry(sdev, 0xC4, sizeof(struct c4_inquiry), h);
        if (err == SCSI_DH_OK) {
                inqp = &h->inq.c4;
                h->ctlr = get_controller(inqp->subsys_id, inqp->slot_id,
                                        array_name);
                if (!h->ctlr)
                        err = SCSI_DH_RES_TEMP_UNAVAIL;
        }
        return err;
}

static int set_mode_select(struct scsi_device *sdev, struct rdac_dh_data *h)
{
        int err;
        struct c2_inquiry *inqp;

        err = submit_inquiry(sdev, 0xC2, sizeof(struct c2_inquiry), h);
        if (err == SCSI_DH_OK) {
                inqp = &h->inq.c2;
                /*
                 * If more than MODE6_MAX_LUN luns are supported, use
                 * mode select 10
                 */
                if (inqp->max_lun_supported >= MODE6_MAX_LUN)
                        h->ctlr->use_ms10 = 1;
                else
                        h->ctlr->use_ms10 = 0;
        }
        return err;
}

static int mode_select_handle_sense(struct scsi_device *sdev,
                                        unsigned char *sensebuf)
{
        struct scsi_sense_hdr sense_hdr;
        int err = SCSI_DH_IO, ret;
        struct rdac_dh_data *h = get_rdac_data(sdev);

        ret = scsi_normalize_sense(sensebuf, SCSI_SENSE_BUFFERSIZE, &sense_hdr);
        if (!ret)
                goto done;

        switch (sense_hdr.sense_key) {
        case NO_SENSE:
        case ABORTED_COMMAND:
        case UNIT_ATTENTION:
                err = SCSI_DH_RETRY;
                break;
        case NOT_READY:
                if (sense_hdr.asc == 0x04 && sense_hdr.ascq == 0x01)
                        /* LUN Not Ready and is in the Process of Becoming
                         * Ready
                         */
                        err = SCSI_DH_RETRY;
                break;
        case ILLEGAL_REQUEST:
                if (sense_hdr.asc == 0x91 && sense_hdr.ascq == 0x36)
                        /*
                         * Command Lock contention
                         */
                        err = SCSI_DH_RETRY;
                break;
        default:
                break;
        }

        RDAC_LOG(RDAC_LOG_FAILOVER, sdev, "array %s, ctlr %d, "
                "MODE_SELECT returned with sense %02x/%02x/%02x",
                (char *) h->ctlr->array_name, h->ctlr->index,
                sense_hdr.sense_key, sense_hdr.asc, sense_hdr.ascq);

done:
        return err;
}

static void send_mode_select(struct work_struct *work)
{
        struct rdac_controller *ctlr =
                container_of(work, struct rdac_controller, ms_work);
        struct request *rq;
        struct scsi_device *sdev = ctlr->ms_sdev;
        struct rdac_dh_data *h = get_rdac_data(sdev);
        struct request_queue *q = sdev->request_queue;
        int err, retry_cnt = RDAC_RETRY_COUNT;
        struct rdac_queue_data *tmp, *qdata;
        LIST_HEAD(list);
        u8 *lun_table;

        spin_lock(&ctlr->ms_lock);
        list_splice_init(&ctlr->ms_head, &list);
        ctlr->ms_queued = 0;
        ctlr->ms_sdev = NULL;
        spin_unlock(&ctlr->ms_lock);

        if (ctlr->use_ms10)
                lun_table = ctlr->mode_select.expanded.lun_table;
        else
                lun_table = ctlr->mode_select.legacy.lun_table;

retry:
        err = SCSI_DH_RES_TEMP_UNAVAIL;
        rq = rdac_failover_get(sdev, h);
        if (!rq)
                goto done;

        list_for_each_entry(qdata, &list, entry) {
                lun_table[qdata->h->lun] = 0x81;
        }

        RDAC_LOG(RDAC_LOG_FAILOVER, sdev, "array %s, ctlr %d, "
                "%s MODE_SELECT command",
                (char *) h->ctlr->array_name, h->ctlr->index,
                (retry_cnt == RDAC_RETRY_COUNT) ? "queueing" : "retrying");

        err = blk_execute_rq(q, NULL, rq, 1);
        blk_put_request(rq);
        if (err != SCSI_DH_OK) {
                err = mode_select_handle_sense(sdev, h->sense);
                if (err == SCSI_DH_RETRY && retry_cnt--)
                        goto retry;
        }
        if (err == SCSI_DH_OK) {
                h->state = RDAC_STATE_ACTIVE;
                RDAC_LOG(RDAC_LOG_FAILOVER, sdev, "array %s, ctlr %d, "
                                "MODE_SELECT completed",
                                (char *) h->ctlr->array_name, h->ctlr->index);
        }

done:
        list_for_each_entry_safe(qdata, tmp, &list, entry) {
                list_del(&qdata->entry);
                if (err == SCSI_DH_OK)
                        qdata->h->state = RDAC_STATE_ACTIVE;
                if (qdata->callback_fn)
                        qdata->callback_fn(qdata->callback_data, err);
                kfree(qdata);
        }
        return;
}

static int queue_mode_select(struct scsi_device *sdev,
                                activate_complete fn, void *data)
{
        struct rdac_queue_data *qdata;
        struct rdac_controller *ctlr;

        qdata = kzalloc(sizeof(*qdata), GFP_KERNEL);
        if (!qdata)
                return SCSI_DH_RETRY;

        qdata->h = get_rdac_data(sdev);
        qdata->callback_fn = fn;
        qdata->callback_data = data;

        ctlr = qdata->h->ctlr;
        spin_lock(&ctlr->ms_lock);
        list_add_tail(&qdata->entry, &ctlr->ms_head);
        if (!ctlr->ms_queued) {
                ctlr->ms_queued = 1;
                ctlr->ms_sdev = sdev;
                queue_work(kmpath_rdacd, &ctlr->ms_work);
        }
        spin_unlock(&ctlr->ms_lock);
        return SCSI_DH_OK;
}

static int rdac_activate(struct scsi_device *sdev,
                        activate_complete fn, void *data)
{
        struct rdac_dh_data *h = get_rdac_data(sdev);
        int err = SCSI_DH_OK;

        err = check_ownership(sdev, h);
        if (err != SCSI_DH_OK)
                goto done;

        if (h->lun_state == RDAC_LUN_UNOWNED) {
                err = queue_mode_select(sdev, fn, data);
                if (err == SCSI_DH_OK)
                        return 0;
        }
done:
        if (fn)
                fn(data, err);
        return 0;
}

static int rdac_prep_fn(struct scsi_device *sdev, struct request *req)
{
        struct rdac_dh_data *h = get_rdac_data(sdev);
        int ret = BLKPREP_OK;

        if (h->state != RDAC_STATE_ACTIVE) {
                ret = BLKPREP_KILL;
                req->cmd_flags |= REQ_QUIET;
        }
        return ret;

}

static int rdac_check_sense(struct scsi_device *sdev,
                                struct scsi_sense_hdr *sense_hdr)
{
        struct rdac_dh_data *h = get_rdac_data(sdev);

        RDAC_LOG(RDAC_LOG_SENSE, sdev, "array %s, ctlr %d, "
                        "I/O returned with sense %02x/%02x/%02x",
                        (char *) h->ctlr->array_name, h->ctlr->index,
                        sense_hdr->sense_key, sense_hdr->asc, sense_hdr->ascq);

        switch (sense_hdr->sense_key) {
        case NOT_READY:
                if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x01)
                        /* LUN Not Ready - Logical Unit Not Ready and is in
                        * the process of becoming ready
                        * Just retry.
                        */
                        return ADD_TO_MLQUEUE;
                if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x81)
                        /* LUN Not Ready - Storage firmware incompatible
                         * Manual code synchonisation required.
                         *
                         * Nothing we can do here. Try to bypass the path.
                         */
                        return SUCCESS;
                if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0xA1)
                        /* LUN Not Ready - Quiescense in progress
                         *
                         * Just retry and wait.
                         */
                        return ADD_TO_MLQUEUE;
                if (sense_hdr->asc == 0xA1  && sense_hdr->ascq == 0x02)
                        /* LUN Not Ready - Quiescense in progress
                         * or has been achieved
                         * Just retry.
                         */
                        return ADD_TO_MLQUEUE;
                break;
        case ILLEGAL_REQUEST:
                if (sense_hdr->asc == 0x94 && sense_hdr->ascq == 0x01) {
                        /* Invalid Request - Current Logical Unit Ownership.
                         * Controller is not the current owner of the LUN,
                         * Fail the path, so that the other path be used.
                         */
                        h->state = RDAC_STATE_PASSIVE;
                        return SUCCESS;
                }
                break;
        case UNIT_ATTENTION:
                if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00)
                        /*
                         * Power On, Reset, or Bus Device Reset, just retry.
                         */
                        return ADD_TO_MLQUEUE;
                if (sense_hdr->asc == 0x8b && sense_hdr->ascq == 0x02)
                        /*
                         * Quiescence in progress , just retry.
                         */
                        return ADD_TO_MLQUEUE;
                break;
        }
        /* success just means we do not care what scsi-ml does */
        return SCSI_RETURN_NOT_HANDLED;
}

static const struct scsi_dh_devlist rdac_dev_list[] = {
        {"IBM", "1722"},
        {"IBM", "1724"},
        {"IBM", "1726"},
        {"IBM", "1742"},
        {"IBM", "1745"},
        {"IBM", "1746"},
        {"IBM", "1814"},
        {"IBM", "1815"},
        {"IBM", "1818"},
        {"IBM", "3526"},
        {"SGI", "TP9400"},
        {"SGI", "TP9500"},
        {"SGI", "IS"},
        {"STK", "OPENstorage D280"},
        {"SUN", "CSM200_R"},
        {"SUN", "LCSM100_I"},
        {"SUN", "LCSM100_S"},
        {"SUN", "LCSM100_E"},
        {"SUN", "LCSM100_F"},
        {"DELL", "MD3000"},
        {"DELL", "MD3000i"},
        {"DELL", "MD32xx"},
        {"DELL", "MD32xxi"},
        {"DELL", "MD36xxi"},
        {"LSI", "INF-01-00"},
        {"ENGENIO", "INF-01-00"},
        {"STK", "FLEXLINE 380"},
        {"SUN", "CSM100_R_FC"},
        {NULL, NULL},
};

static int rdac_bus_attach(struct scsi_device *sdev);
static void rdac_bus_detach(struct scsi_device *sdev);

static struct scsi_device_handler rdac_dh = {
        .name = RDAC_NAME,
        .module = THIS_MODULE,
        .devlist = rdac_dev_list,
        .prep_fn = rdac_prep_fn,
        .check_sense = rdac_check_sense,
        .attach = rdac_bus_attach,
        .detach = rdac_bus_detach,
        .activate = rdac_activate,
};

static int rdac_bus_attach(struct scsi_device *sdev)
{
        struct scsi_dh_data *scsi_dh_data;
        struct rdac_dh_data *h;
        unsigned long flags;
        int err;
        char array_name[ARRAY_LABEL_LEN];

        scsi_dh_data = kzalloc(sizeof(struct scsi_device_handler *)
                               + sizeof(*h) , GFP_KERNEL);
        if (!scsi_dh_data) {
                sdev_printk(KERN_ERR, sdev, "%s: Attach failed\n",
                            RDAC_NAME);
                return 0;
        }

        scsi_dh_data->scsi_dh = &rdac_dh;
        h = (struct rdac_dh_data *) scsi_dh_data->buf;
        h->lun = UNINITIALIZED_LUN;
        h->state = RDAC_STATE_ACTIVE;

        err = get_lun_info(sdev, h, array_name);
        if (err != SCSI_DH_OK)
                goto failed;

        err = initialize_controller(sdev, h, array_name);
        if (err != SCSI_DH_OK)
                goto failed;

        err = check_ownership(sdev, h);
        if (err != SCSI_DH_OK)
                goto clean_ctlr;

        err = set_mode_select(sdev, h);
        if (err != SCSI_DH_OK)
                goto clean_ctlr;

        if (!try_module_get(THIS_MODULE))
                goto clean_ctlr;

        spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
        sdev->scsi_dh_data = scsi_dh_data;
        spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);

        sdev_printk(KERN_NOTICE, sdev,
                    "%s: LUN %d (%s)\n",
                    RDAC_NAME, h->lun, lun_state[(int)h->lun_state]);

        return 0;

clean_ctlr:
        kref_put(&h->ctlr->kref, release_controller);

failed:
        kfree(scsi_dh_data);
        sdev_printk(KERN_ERR, sdev, "%s: not attached\n",
                    RDAC_NAME);
        return -EINVAL;
}

static void rdac_bus_detach( struct scsi_device *sdev )
{
        struct scsi_dh_data *scsi_dh_data;
        struct rdac_dh_data *h;
        unsigned long flags;

        spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
        scsi_dh_data = sdev->scsi_dh_data;
        sdev->scsi_dh_data = NULL;
        spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);

        h = (struct rdac_dh_data *) scsi_dh_data->buf;
        if (h->ctlr)
                kref_put(&h->ctlr->kref, release_controller);
        kfree(scsi_dh_data);
        module_put(THIS_MODULE);
        sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", RDAC_NAME);
}



static int __init rdac_init(void)
{
        int r;

        r = scsi_register_device_handler(&rdac_dh);
        if (r != 0) {
                printk(KERN_ERR "Failed to register scsi device handler.");
                goto done;
        }

        /*
         * Create workqueue to handle mode selects for rdac
         */
        kmpath_rdacd = create_singlethread_workqueue("kmpath_rdacd");
        if (!kmpath_rdacd) {
                scsi_unregister_device_handler(&rdac_dh);
                printk(KERN_ERR "kmpath_rdacd creation failed.\n");
        }
done:
        return r;
}

static void __exit rdac_exit(void)
{
        destroy_workqueue(kmpath_rdacd);
        scsi_unregister_device_handler(&rdac_dh);
}

module_init(rdac_init);
module_exit(rdac_exit);

MODULE_DESCRIPTION("Multipath LSI/Engenio RDAC driver");
MODULE_AUTHOR("Mike Christie, Chandra Seetharaman");
MODULE_LICENSE("GPL");