scsi_dh_emc.c

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/*
 * Target driver for EMC CLARiiON AX/CX-series hardware.
 * Based on code from Lars Marowsky-Bree <[email protected]>
 * and Ed Goggin <[email protected]>.
 *
 * Copyright (C) 2006 Red Hat, Inc.  All rights reserved.
 * Copyright (C) 2006 Mike Christie
 *
 * 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, 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; see the file COPYING.  If not, write to
 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
 */
#include <linux/slab.h>
#include <linux/module.h>
#include <scsi/scsi.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_dh.h>
#include <scsi/scsi_device.h>

#define CLARIION_NAME           "emc"

#define CLARIION_TRESPASS_PAGE      0x22
#define CLARIION_BUFFER_SIZE        0xFC
#define CLARIION_TIMEOUT        (60 * HZ)
#define CLARIION_RETRIES        3
#define CLARIION_UNBOUND_LU     -1
#define CLARIION_SP_A           0
#define CLARIION_SP_B           1

/* Flags */
#define CLARIION_SHORT_TRESPASS     1
#define CLARIION_HONOR_RESERVATIONS 2

/* LUN states */
#define CLARIION_LUN_UNINITIALIZED  -1
#define CLARIION_LUN_UNBOUND        0
#define CLARIION_LUN_BOUND      1
#define CLARIION_LUN_OWNED      2

static unsigned char long_trespass[] = {
    0, 0, 0, 0, 0, 0, 0, 0,
    CLARIION_TRESPASS_PAGE, /* Page code */
    0x09,           /* Page length - 2 */
    0x01,           /* Trespass code */
    0xff, 0xff,     /* Trespass target */
    0, 0, 0, 0, 0, 0    /* Reserved bytes / unknown */
};

static unsigned char short_trespass[] = {
    0, 0, 0, 0,
    CLARIION_TRESPASS_PAGE, /* Page code */
    0x02,           /* Page length - 2 */
    0x01,           /* Trespass code */
    0xff,           /* Trespass target */
};

static const char * lun_state[] =
{
    "not bound",
    "bound",
    "owned",
};

struct clariion_dh_data {
    /*
     * Flags:
     *  CLARIION_SHORT_TRESPASS
     * Use short trespass command (FC-series) or the long version
     * (default for AX/CX CLARiiON arrays).
     *
     *  CLARIION_HONOR_RESERVATIONS
     * Whether or not (default) to honor SCSI reservations when
     * initiating a switch-over.
     */
    unsigned flags;
    /*
     * I/O buffer for both MODE_SELECT and INQUIRY commands.
     */
    unsigned char buffer[CLARIION_BUFFER_SIZE];
    /*
     * SCSI sense buffer for commands -- assumes serial issuance
     * and completion sequence of all commands for same multipath.
     */
    unsigned char sense[SCSI_SENSE_BUFFERSIZE];
    unsigned int senselen;
    /*
     * LUN state
     */
    int lun_state;
    /*
     * SP Port number
     */
    int port;
    /*
     * which SP (A=0,B=1,UNBOUND=-1) is the default SP for this
     * path's mapped LUN
     */
    int default_sp;
    /*
     * which SP (A=0,B=1,UNBOUND=-1) is the active SP for this
     * path's mapped LUN
     */
    int current_sp;
};

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

/*
 * Parse MODE_SELECT cmd reply.
 */
static int trespass_endio(struct scsi_device *sdev, char *sense)
{
    int err = SCSI_DH_IO;
    struct scsi_sense_hdr sshdr;

    if (!scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, &sshdr)) {
        sdev_printk(KERN_ERR, sdev, "%s: Found valid sense data 0x%2x, "
                "0x%2x, 0x%2x while sending CLARiiON trespass "
                "command.\n", CLARIION_NAME, sshdr.sense_key,
                sshdr.asc, sshdr.ascq);

        if ((sshdr.sense_key == 0x05) && (sshdr.asc == 0x04) &&
             (sshdr.ascq == 0x00)) {
            /*
             * Array based copy in progress -- do not send
             * mode_select or copy will be aborted mid-stream.
             */
            sdev_printk(KERN_INFO, sdev, "%s: Array Based Copy in "
                    "progress while sending CLARiiON trespass "
                    "command.\n", CLARIION_NAME);
            err = SCSI_DH_DEV_TEMP_BUSY;
        } else if ((sshdr.sense_key == 0x02) && (sshdr.asc == 0x04) &&
                (sshdr.ascq == 0x03)) {
            /*
             * LUN Not Ready - Manual Intervention Required
             * indicates in-progress ucode upgrade (NDU).
             */
            sdev_printk(KERN_INFO, sdev, "%s: Detected in-progress "
                    "ucode upgrade NDU operation while sending "
                    "CLARiiON trespass command.\n", CLARIION_NAME);
            err = SCSI_DH_DEV_TEMP_BUSY;
        } else
            err = SCSI_DH_DEV_FAILED;
    } else {
        sdev_printk(KERN_INFO, sdev,
                "%s: failed to send MODE SELECT, no sense available\n",
                CLARIION_NAME);
    }
    return err;
}

static int parse_sp_info_reply(struct scsi_device *sdev,
                   struct clariion_dh_data *csdev)
{
    int err = SCSI_DH_OK;

    /* check for in-progress ucode upgrade (NDU) */
    if (csdev->buffer[48] != 0) {
        sdev_printk(KERN_NOTICE, sdev, "%s: Detected in-progress "
                "ucode upgrade NDU operation while finding "
                "current active SP.", CLARIION_NAME);
        err = SCSI_DH_DEV_TEMP_BUSY;
        goto out;
    }
    if (csdev->buffer[4] > 2) {
        /* Invalid buffer format */
        sdev_printk(KERN_NOTICE, sdev,
                "%s: invalid VPD page 0xC0 format\n",
                CLARIION_NAME);
        err = SCSI_DH_NOSYS;
        goto out;
    }
    switch (csdev->buffer[28] & 0x0f) {
    case 6:
        sdev_printk(KERN_NOTICE, sdev,
                "%s: ALUA failover mode detected\n",
                CLARIION_NAME);
        break;
    case 4:
        /* Linux failover */
        break;
    default:
        sdev_printk(KERN_WARNING, sdev,
                "%s: Invalid failover mode %d\n",
                CLARIION_NAME, csdev->buffer[28] & 0x0f);
        err = SCSI_DH_NOSYS;
        goto out;
    }

    csdev->default_sp = csdev->buffer[5];
    csdev->lun_state = csdev->buffer[4];
    csdev->current_sp = csdev->buffer[8];
    csdev->port = csdev->buffer[7];

out:
    return err;
}

#define emc_default_str "FC (Legacy)"

static char * parse_sp_model(struct scsi_device *sdev, unsigned char *buffer)
{
    unsigned char len = buffer[4] + 5;
    char *sp_model = NULL;
    unsigned char sp_len, serial_len;

    if (len < 160) {
        sdev_printk(KERN_WARNING, sdev,
                "%s: Invalid information section length %d\n",
                CLARIION_NAME, len);
        /* Check for old FC arrays */
        if (!strncmp(buffer + 8, "DGC", 3)) {
            /* Old FC array, not supporting extended information */
            sp_model = emc_default_str;
        }
        goto out;
    }

    /*
     * Parse extended information for SP model number
     */
    serial_len = buffer[160];
    if (serial_len == 0 || serial_len + 161 > len) {
        sdev_printk(KERN_WARNING, sdev,
                "%s: Invalid array serial number length %d\n",
                CLARIION_NAME, serial_len);
        goto out;
    }
    sp_len = buffer[99];
    if (sp_len == 0 || serial_len + sp_len + 161 > len) {
        sdev_printk(KERN_WARNING, sdev,
                "%s: Invalid model number length %d\n",
                CLARIION_NAME, sp_len);
        goto out;
    }
    sp_model = &buffer[serial_len + 161];
    /* Strip whitespace at the end */
    while (sp_len > 1 && sp_model[sp_len - 1] == ' ')
        sp_len--;

    sp_model[sp_len] = '\0';

out:
    return sp_model;
}

/*
 * Get block request for REQ_BLOCK_PC command issued to path.  Currently
 * limited to MODE_SELECT (trespass) and INQUIRY (VPD page 0xC0) commands.
 *
 * Uses data and sense buffers in hardware handler context structure and
 * assumes serial servicing of commands, both issuance and completion.
 */
static struct request *get_req(struct scsi_device *sdev, int cmd,
                unsigned char *buffer)
{
    struct request *rq;
    int len = 0;

    rq = blk_get_request(sdev->request_queue,
            (cmd != INQUIRY) ? WRITE : READ, GFP_NOIO);
    if (!rq) {
        sdev_printk(KERN_INFO, sdev, "get_req: blk_get_request failed");
        return NULL;
    }

    rq->cmd_len = COMMAND_SIZE(cmd);
    rq->cmd[0] = cmd;

    switch (cmd) {
    case MODE_SELECT:
        len = sizeof(short_trespass);
        rq->cmd[1] = 0x10;
        rq->cmd[4] = len;
        break;
    case MODE_SELECT_10:
        len = sizeof(long_trespass);
        rq->cmd[1] = 0x10;
        rq->cmd[8] = len;
        break;
    case INQUIRY:
        len = CLARIION_BUFFER_SIZE;
        rq->cmd[4] = len;
        memset(buffer, 0, len);
        break;
    default:
        BUG_ON(1);
        break;
    }

    rq->cmd_type = REQ_TYPE_BLOCK_PC;
    rq->cmd_flags |= REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
             REQ_FAILFAST_DRIVER;
    rq->timeout = CLARIION_TIMEOUT;
    rq->retries = CLARIION_RETRIES;

    if (blk_rq_map_kern(rq->q, rq, buffer, len, GFP_NOIO)) {
        blk_put_request(rq);
        return NULL;
    }

    return rq;
}

static int send_inquiry_cmd(struct scsi_device *sdev, int page,
                struct clariion_dh_data *csdev)
{
    struct request *rq = get_req(sdev, INQUIRY, csdev->buffer);
    int err;

    if (!rq)
        return SCSI_DH_RES_TEMP_UNAVAIL;

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

    rq->cmd[0] = INQUIRY;
    if (page != 0) {
        rq->cmd[1] = 1;
        rq->cmd[2] = page;
    }
    err = blk_execute_rq(sdev->request_queue, NULL, rq, 1);
    if (err == -EIO) {
        sdev_printk(KERN_INFO, sdev,
                "%s: failed to send %s INQUIRY: %x\n",
                CLARIION_NAME, page?"EVPD":"standard",
                rq->errors);
        csdev->senselen = rq->sense_len;
        err = SCSI_DH_IO;
    }

    blk_put_request(rq);

    return err;
}

static int send_trespass_cmd(struct scsi_device *sdev,
                struct clariion_dh_data *csdev)
{
    struct request *rq;
    unsigned char *page22;
    int err, len, cmd;

    if (csdev->flags & CLARIION_SHORT_TRESPASS) {
        page22 = short_trespass;
        if (!(csdev->flags & CLARIION_HONOR_RESERVATIONS))
            /* Set Honor Reservations bit */
            page22[6] |= 0x80;
        len = sizeof(short_trespass);
        cmd = MODE_SELECT;
    } else {
        page22 = long_trespass;
        if (!(csdev->flags & CLARIION_HONOR_RESERVATIONS))
            /* Set Honor Reservations bit */
            page22[10] |= 0x80;
        len = sizeof(long_trespass);
        cmd = MODE_SELECT_10;
    }
    BUG_ON((len > CLARIION_BUFFER_SIZE));
    memcpy(csdev->buffer, page22, len);

    rq = get_req(sdev, cmd, csdev->buffer);
    if (!rq)
        return SCSI_DH_RES_TEMP_UNAVAIL;

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

    err = blk_execute_rq(sdev->request_queue, NULL, rq, 1);
    if (err == -EIO) {
        if (rq->sense_len) {
            err = trespass_endio(sdev, csdev->sense);
        } else {
            sdev_printk(KERN_INFO, sdev,
                    "%s: failed to send MODE SELECT: %x\n",
                    CLARIION_NAME, rq->errors);
        }
    }

    blk_put_request(rq);

    return err;
}

static int clariion_check_sense(struct scsi_device *sdev,
                struct scsi_sense_hdr *sense_hdr)
{
    switch (sense_hdr->sense_key) {
    case NOT_READY:
        if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x03)
            /*
             * LUN Not Ready - Manual Intervention Required
             * indicates this is a passive path.
             *
             * FIXME: However, if this is seen and EVPD C0
             * indicates that this is due to a NDU in
             * progress, we should set FAIL_PATH too.
             * This indicates we might have to do a SCSI
             * inquiry in the end_io path. Ugh.
             *
             * Can return FAILED only when we want the error
             * recovery process to kick in.
             */
            return SUCCESS;
        break;
    case ILLEGAL_REQUEST:
        if (sense_hdr->asc == 0x25 && sense_hdr->ascq == 0x01)
            /*
             * An array based copy is in progress. Do not
             * fail the path, do not bypass to another PG,
             * do not retry. Fail the IO immediately.
             * (Actually this is the same conclusion as in
             * the default handler, but lets make sure.)
             *
             * Can return FAILED only when we want the error
             * recovery process to kick in.
             */
            return SUCCESS;
        break;
    case UNIT_ATTENTION:
        if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00)
            /*
             * Unit Attention Code. This is the first IO
             * to the new path, so just retry.
             */
            return ADD_TO_MLQUEUE;
        break;
    }

    return SCSI_RETURN_NOT_HANDLED;
}

static int clariion_prep_fn(struct scsi_device *sdev, struct request *req)
{
    struct clariion_dh_data *h = get_clariion_data(sdev);
    int ret = BLKPREP_OK;

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

}

static int clariion_std_inquiry(struct scsi_device *sdev,
                struct clariion_dh_data *csdev)
{
    int err;
    char *sp_model;

    err = send_inquiry_cmd(sdev, 0, csdev);
    if (err != SCSI_DH_OK && csdev->senselen) {
        struct scsi_sense_hdr sshdr;

        if (scsi_normalize_sense(csdev->sense, SCSI_SENSE_BUFFERSIZE,
                     &sshdr)) {
            sdev_printk(KERN_ERR, sdev, "%s: INQUIRY sense code "
                    "%02x/%02x/%02x\n", CLARIION_NAME,
                    sshdr.sense_key, sshdr.asc, sshdr.ascq);
        }
        err = SCSI_DH_IO;
        goto out;
    }

    sp_model = parse_sp_model(sdev, csdev->buffer);
    if (!sp_model) {
        err = SCSI_DH_DEV_UNSUPP;
        goto out;
    }

    /*
     * FC Series arrays do not support long trespass
     */
    if (!strlen(sp_model) || !strncmp(sp_model, "FC",2))
        csdev->flags |= CLARIION_SHORT_TRESPASS;

    sdev_printk(KERN_INFO, sdev,
            "%s: detected Clariion %s, flags %x\n",
            CLARIION_NAME, sp_model, csdev->flags);
out:
    return err;
}

static int clariion_send_inquiry(struct scsi_device *sdev,
                 struct clariion_dh_data *csdev)
{
    int err, retry = CLARIION_RETRIES;

retry:
    err = send_inquiry_cmd(sdev, 0xC0, csdev);
    if (err != SCSI_DH_OK && csdev->senselen) {
        struct scsi_sense_hdr sshdr;

        err = scsi_normalize_sense(csdev->sense, SCSI_SENSE_BUFFERSIZE,
                       &sshdr);
        if (!err)
            return SCSI_DH_IO;

        err = clariion_check_sense(sdev, &sshdr);
        if (retry > 0 && err == ADD_TO_MLQUEUE) {
            retry--;
            goto retry;
        }
        sdev_printk(KERN_ERR, sdev, "%s: INQUIRY sense code "
                "%02x/%02x/%02x\n", CLARIION_NAME,
                  sshdr.sense_key, sshdr.asc, sshdr.ascq);
        err = SCSI_DH_IO;
    } else {
        err = parse_sp_info_reply(sdev, csdev);
    }
    return err;
}

static int clariion_activate(struct scsi_device *sdev,
                activate_complete fn, void *data)
{
    struct clariion_dh_data *csdev = get_clariion_data(sdev);
    int result;

    result = clariion_send_inquiry(sdev, csdev);
    if (result != SCSI_DH_OK)
        goto done;

    if (csdev->lun_state == CLARIION_LUN_OWNED)
        goto done;

    result = send_trespass_cmd(sdev, csdev);
    if (result != SCSI_DH_OK)
        goto done;
    sdev_printk(KERN_INFO, sdev,"%s: %s trespass command sent\n",
            CLARIION_NAME,
            csdev->flags&CLARIION_SHORT_TRESPASS?"short":"long" );

    /* Update status */
    result = clariion_send_inquiry(sdev, csdev);
    if (result != SCSI_DH_OK)
        goto done;

done:
    sdev_printk(KERN_INFO, sdev,
            "%s: at SP %c Port %d (%s, default SP %c)\n",
            CLARIION_NAME, csdev->current_sp + 'A',
            csdev->port, lun_state[csdev->lun_state],
            csdev->default_sp + 'A');

    if (fn)
        fn(data, result);
    return 0;
}
/*
 * params - parameters in the following format
 *      "no_of_params\0param1\0param2\0param3\0...\0"
 *      for example, string for 2 parameters with value 10 and 21
 *      is specified as "2\010\021\0".
 */
static int clariion_set_params(struct scsi_device *sdev, const char *params)
{
    struct clariion_dh_data *csdev = get_clariion_data(sdev);
    unsigned int hr = 0, st = 0, argc;
    const char *p = params;
    int result = SCSI_DH_OK;

    if ((sscanf(params, "%u", &argc) != 1) || (argc != 2))
        return -EINVAL;

    while (*p++)
        ;
    if ((sscanf(p, "%u", &st) != 1) || (st > 1))
        return -EINVAL;

    while (*p++)
        ;
    if ((sscanf(p, "%u", &hr) != 1) || (hr > 1))
        return -EINVAL;

    if (st)
        csdev->flags |= CLARIION_SHORT_TRESPASS;
    else
        csdev->flags &= ~CLARIION_SHORT_TRESPASS;

    if (hr)
        csdev->flags |= CLARIION_HONOR_RESERVATIONS;
    else
        csdev->flags &= ~CLARIION_HONOR_RESERVATIONS;

    /*
     * If this path is owned, we have to send a trespass command
     * with the new parameters. If not, simply return. Next trespass
     * command would use the parameters.
     */
    if (csdev->lun_state != CLARIION_LUN_OWNED)
        goto done;

    csdev->lun_state = CLARIION_LUN_UNINITIALIZED;
    result = send_trespass_cmd(sdev, csdev);
    if (result != SCSI_DH_OK)
        goto done;

    /* Update status */
    result = clariion_send_inquiry(sdev, csdev);

done:
    return result;
}

static const struct scsi_dh_devlist clariion_dev_list[] = {
    {"DGC", "RAID"},
    {"DGC", "DISK"},
    {"DGC", "VRAID"},
    {NULL, NULL},
};

static bool clariion_match(struct scsi_device *sdev)
{
    int i;

    if (scsi_device_tpgs(sdev))
        return false;

    for (i = 0; clariion_dev_list[i].vendor; i++) {
        if (!strncmp(sdev->vendor, clariion_dev_list[i].vendor,
            strlen(clariion_dev_list[i].vendor)) &&
            !strncmp(sdev->model, clariion_dev_list[i].model,
            strlen(clariion_dev_list[i].model))) {
            return true;
        }
    }
    return false;
}

static int clariion_bus_attach(struct scsi_device *sdev);
static void clariion_bus_detach(struct scsi_device *sdev);

static struct scsi_device_handler clariion_dh = {
    .name       = CLARIION_NAME,
    .module     = THIS_MODULE,
    .devlist    = clariion_dev_list,
    .attach     = clariion_bus_attach,
    .detach     = clariion_bus_detach,
    .check_sense    = clariion_check_sense,
    .activate   = clariion_activate,
    .prep_fn    = clariion_prep_fn,
    .set_params = clariion_set_params,
    .match      = clariion_match,
};

static int clariion_bus_attach(struct scsi_device *sdev)
{
    struct scsi_dh_data *scsi_dh_data;
    struct clariion_dh_data *h;
    unsigned long flags;
    int err;

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

    scsi_dh_data->scsi_dh = &clariion_dh;
    h = (struct clariion_dh_data *) scsi_dh_data->buf;
    h->lun_state = CLARIION_LUN_UNINITIALIZED;
    h->default_sp = CLARIION_UNBOUND_LU;
    h->current_sp = CLARIION_UNBOUND_LU;

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

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

    if (!try_module_get(THIS_MODULE))
        goto failed;

    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_INFO, sdev,
            "%s: connected to SP %c Port %d (%s, default SP %c)\n",
            CLARIION_NAME, h->current_sp + 'A',
            h->port, lun_state[h->lun_state],
            h->default_sp + 'A');

    return 0;

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

static void clariion_bus_detach(struct scsi_device *sdev)
{
    struct scsi_dh_data *scsi_dh_data;
    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);

    sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n",
            CLARIION_NAME);

    kfree(scsi_dh_data);
    module_put(THIS_MODULE);
}

static int __init clariion_init(void)
{
    int r;

    r = scsi_register_device_handler(&clariion_dh);
    if (r != 0)
        printk(KERN_ERR "%s: Failed to register scsi device handler.",
            CLARIION_NAME);
    return r;
}

static void __exit clariion_exit(void)
{
    scsi_unregister_device_handler(&clariion_dh);
}

module_init(clariion_init);
module_exit(clariion_exit);

MODULE_DESCRIPTION("EMC CX/AX/FC-family driver");
MODULE_AUTHOR("Mike Christie <[email protected]>, Chandra Seetharaman <[email protected]>");
MODULE_LICENSE("GPL");