scsi_dh_hp_sw.c

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/*
 * Basic HP/COMPAQ MSA 1000 support. This is only needed if your HW cannot be
 * upgraded.
 *
 * Copyright (C) 2006 Red Hat, Inc.  All rights reserved.
 * Copyright (C) 2006 Mike Christie
 * Copyright (C) 2008 Hannes Reinecke <[email protected]>
 *
 * 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_dbg.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_dh.h>

#define HP_SW_NAME          "hp_sw"

#define HP_SW_TIMEOUT           (60 * HZ)
#define HP_SW_RETRIES           3

#define HP_SW_PATH_UNINITIALIZED    -1
#define HP_SW_PATH_ACTIVE       0
#define HP_SW_PATH_PASSIVE      1

struct hp_sw_dh_data {
    unsigned char sense[SCSI_SENSE_BUFFERSIZE];
    int path_state;
    int retries;
    int retry_cnt;
    struct scsi_device *sdev;
    activate_complete   callback_fn;
    void            *callback_data;
};

static int hp_sw_start_stop(struct hp_sw_dh_data *);

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

/*
 * tur_done - Handle TEST UNIT READY return status
 * @sdev: sdev the command has been sent to
 * @errors: blk error code
 *
 * Returns SCSI_DH_DEV_OFFLINED if the sdev is on the passive path
 */
static int tur_done(struct scsi_device *sdev, unsigned char *sense)
{
    struct scsi_sense_hdr sshdr;
    int ret;

    ret = scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, &sshdr);
    if (!ret) {
        sdev_printk(KERN_WARNING, sdev,
                "%s: sending tur failed, no sense available\n",
                HP_SW_NAME);
        ret = SCSI_DH_IO;
        goto done;
    }
    switch (sshdr.sense_key) {
    case UNIT_ATTENTION:
        ret = SCSI_DH_IMM_RETRY;
        break;
    case NOT_READY:
        if ((sshdr.asc == 0x04) && (sshdr.ascq == 2)) {
            /*
             * LUN not ready - Initialization command required
             *
             * This is the passive path
             */
            ret = SCSI_DH_DEV_OFFLINED;
            break;
        }
        /* Fallthrough */
    default:
        sdev_printk(KERN_WARNING, sdev,
               "%s: sending tur failed, sense %x/%x/%x\n",
               HP_SW_NAME, sshdr.sense_key, sshdr.asc,
               sshdr.ascq);
        break;
    }

done:
    return ret;
}

/*
 * hp_sw_tur - Send TEST UNIT READY
 * @sdev: sdev command should be sent to
 *
 * Use the TEST UNIT READY command to determine
 * the path state.
 */
static int hp_sw_tur(struct scsi_device *sdev, struct hp_sw_dh_data *h)
{
    struct request *req;
    int ret;

retry:
    req = blk_get_request(sdev->request_queue, WRITE, GFP_NOIO);
    if (!req)
        return SCSI_DH_RES_TEMP_UNAVAIL;

    req->cmd_type = REQ_TYPE_BLOCK_PC;
    req->cmd_flags |= REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
              REQ_FAILFAST_DRIVER;
    req->cmd_len = COMMAND_SIZE(TEST_UNIT_READY);
    req->cmd[0] = TEST_UNIT_READY;
    req->timeout = HP_SW_TIMEOUT;
    req->sense = h->sense;
    memset(req->sense, 0, SCSI_SENSE_BUFFERSIZE);
    req->sense_len = 0;

    ret = blk_execute_rq(req->q, NULL, req, 1);
    if (ret == -EIO) {
        if (req->sense_len > 0) {
            ret = tur_done(sdev, h->sense);
        } else {
            sdev_printk(KERN_WARNING, sdev,
                    "%s: sending tur failed with %x\n",
                    HP_SW_NAME, req->errors);
            ret = SCSI_DH_IO;
        }
    } else {
        h->path_state = HP_SW_PATH_ACTIVE;
        ret = SCSI_DH_OK;
    }
    if (ret == SCSI_DH_IMM_RETRY) {
        blk_put_request(req);
        goto retry;
    }
    if (ret == SCSI_DH_DEV_OFFLINED) {
        h->path_state = HP_SW_PATH_PASSIVE;
        ret = SCSI_DH_OK;
    }

    blk_put_request(req);

    return ret;
}

/*
 * start_done - Handle START STOP UNIT return status
 * @sdev: sdev the command has been sent to
 * @errors: blk error code
 */
static int start_done(struct scsi_device *sdev, unsigned char *sense)
{
    struct scsi_sense_hdr sshdr;
    int rc;

    rc = scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, &sshdr);
    if (!rc) {
        sdev_printk(KERN_WARNING, sdev,
                "%s: sending start_stop_unit failed, "
                "no sense available\n",
                HP_SW_NAME);
        return SCSI_DH_IO;
    }
    switch (sshdr.sense_key) {
    case NOT_READY:
        if ((sshdr.asc == 0x04) && (sshdr.ascq == 3)) {
            /*
             * LUN not ready - manual intervention required
             *
             * Switch-over in progress, retry.
             */
            rc = SCSI_DH_RETRY;
            break;
        }
        /* fall through */
    default:
        sdev_printk(KERN_WARNING, sdev,
               "%s: sending start_stop_unit failed, sense %x/%x/%x\n",
               HP_SW_NAME, sshdr.sense_key, sshdr.asc,
               sshdr.ascq);
        rc = SCSI_DH_IO;
    }

    return rc;
}

static void start_stop_endio(struct request *req, int error)
{
    struct hp_sw_dh_data *h = req->end_io_data;
    unsigned err = SCSI_DH_OK;

    if (error || host_byte(req->errors) != DID_OK ||
            msg_byte(req->errors) != COMMAND_COMPLETE) {
        sdev_printk(KERN_WARNING, h->sdev,
                "%s: sending start_stop_unit failed with %x\n",
                HP_SW_NAME, req->errors);
        err = SCSI_DH_IO;
        goto done;
    }

    if (req->sense_len > 0) {
        err = start_done(h->sdev, h->sense);
        if (err == SCSI_DH_RETRY) {
            err = SCSI_DH_IO;
            if (--h->retry_cnt) {
                blk_put_request(req);
                err = hp_sw_start_stop(h);
                if (err == SCSI_DH_OK)
                    return;
            }
        }
    }
done:
    req->end_io_data = NULL;
    __blk_put_request(req->q, req);
    if (h->callback_fn) {
        h->callback_fn(h->callback_data, err);
        h->callback_fn = h->callback_data = NULL;
    }
    return;

}

/*
 * hp_sw_start_stop - Send START STOP UNIT command
 * @sdev: sdev command should be sent to
 *
 * Sending START STOP UNIT activates the SP.
 */
static int hp_sw_start_stop(struct hp_sw_dh_data *h)
{
    struct request *req;

    req = blk_get_request(h->sdev->request_queue, WRITE, GFP_ATOMIC);
    if (!req)
        return SCSI_DH_RES_TEMP_UNAVAIL;

    req->cmd_type = REQ_TYPE_BLOCK_PC;
    req->cmd_flags |= REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
              REQ_FAILFAST_DRIVER;
    req->cmd_len = COMMAND_SIZE(START_STOP);
    req->cmd[0] = START_STOP;
    req->cmd[4] = 1;    /* Start spin cycle */
    req->timeout = HP_SW_TIMEOUT;
    req->sense = h->sense;
    memset(req->sense, 0, SCSI_SENSE_BUFFERSIZE);
    req->sense_len = 0;
    req->end_io_data = h;

    blk_execute_rq_nowait(req->q, NULL, req, 1, start_stop_endio);
    return SCSI_DH_OK;
}

static int hp_sw_prep_fn(struct scsi_device *sdev, struct request *req)
{
    struct hp_sw_dh_data *h = get_hp_sw_data(sdev);
    int ret = BLKPREP_OK;

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

}

/*
 * hp_sw_activate - Activate a path
 * @sdev: sdev on the path to be activated
 *
 * The HP Active/Passive firmware is pretty simple;
 * the passive path reports NOT READY with sense codes
 * 0x04/0x02; a START STOP UNIT command will then
 * activate the passive path (and deactivate the
 * previously active one).
 */
static int hp_sw_activate(struct scsi_device *sdev,
                activate_complete fn, void *data)
{
    int ret = SCSI_DH_OK;
    struct hp_sw_dh_data *h = get_hp_sw_data(sdev);

    ret = hp_sw_tur(sdev, h);

    if (ret == SCSI_DH_OK && h->path_state == HP_SW_PATH_PASSIVE) {
        h->retry_cnt = h->retries;
        h->callback_fn = fn;
        h->callback_data = data;
        ret = hp_sw_start_stop(h);
        if (ret == SCSI_DH_OK)
            return 0;
        h->callback_fn = h->callback_data = NULL;
    }

    if (fn)
        fn(data, ret);
    return 0;
}

static const struct scsi_dh_devlist hp_sw_dh_data_list[] = {
    {"COMPAQ", "MSA1000 VOLUME"},
    {"COMPAQ", "HSV110"},
    {"HP", "HSV100"},
    {"DEC", "HSG80"},
    {NULL, NULL},
};

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

    if (scsi_device_tpgs(sdev))
        return false;

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

static int hp_sw_bus_attach(struct scsi_device *sdev);
static void hp_sw_bus_detach(struct scsi_device *sdev);

static struct scsi_device_handler hp_sw_dh = {
    .name       = HP_SW_NAME,
    .module     = THIS_MODULE,
    .devlist    = hp_sw_dh_data_list,
    .attach     = hp_sw_bus_attach,
    .detach     = hp_sw_bus_detach,
    .activate   = hp_sw_activate,
    .prep_fn    = hp_sw_prep_fn,
    .match      = hp_sw_match,
};

static int hp_sw_bus_attach(struct scsi_device *sdev)
{
    struct scsi_dh_data *scsi_dh_data;
    struct hp_sw_dh_data *h;
    unsigned long flags;
    int ret;

    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",
                HP_SW_NAME);
        return 0;
    }

    scsi_dh_data->scsi_dh = &hp_sw_dh;
    h = (struct hp_sw_dh_data *) scsi_dh_data->buf;
    h->path_state = HP_SW_PATH_UNINITIALIZED;
    h->retries = HP_SW_RETRIES;
    h->sdev = sdev;

    ret = hp_sw_tur(sdev, h);
    if (ret != SCSI_DH_OK || h->path_state == HP_SW_PATH_UNINITIALIZED)
        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: attached to %s path\n",
            HP_SW_NAME, h->path_state == HP_SW_PATH_ACTIVE?
            "active":"passive");

    return 0;

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

static void hp_sw_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);
    module_put(THIS_MODULE);

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

    kfree(scsi_dh_data);
}

static int __init hp_sw_init(void)
{
    return scsi_register_device_handler(&hp_sw_dh);
}

static void __exit hp_sw_exit(void)
{
    scsi_unregister_device_handler(&hp_sw_dh);
}

module_init(hp_sw_init);
module_exit(hp_sw_exit);

MODULE_DESCRIPTION("HP Active/Passive driver");
MODULE_AUTHOR("Mike Christie <[email protected]");
MODULE_LICENSE("GPL");