Pull sbs into release branch

[linux-2.6] / drivers / message / i2o / i2o_block.c

/*
 *      Block OSM
 *
 *      Copyright (C) 1999-2002 Red Hat Software
 *
 *      Written by Alan Cox, Building Number Three Ltd
 *
 *      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.
 *
 *      For the purpose of avoiding doubt the preferred form of the work
 *      for making modifications shall be a standards compliant form such
 *      gzipped tar and not one requiring a proprietary or patent encumbered
 *      tool to unpack.
 *
 *      Fixes/additions:
 *              Steve Ralston:
 *                      Multiple device handling error fixes,
 *                      Added a queue depth.
 *              Alan Cox:
 *                      FC920 has an rmw bug. Dont or in the end marker.
 *                      Removed queue walk, fixed for 64bitness.
 *                      Rewrote much of the code over time
 *                      Added indirect block lists
 *                      Handle 64K limits on many controllers
 *                      Don't use indirects on the Promise (breaks)
 *                      Heavily chop down the queue depths
 *              Deepak Saxena:
 *                      Independent queues per IOP
 *                      Support for dynamic device creation/deletion
 *                      Code cleanup
 *                      Support for larger I/Os through merge* functions
 *                      (taken from DAC960 driver)
 *              Boji T Kannanthanam:
 *                      Set the I2O Block devices to be detected in increasing
 *                      order of TIDs during boot.
 *                      Search and set the I2O block device that we boot off
 *                      from as the first device to be claimed (as /dev/i2o/hda)
 *                      Properly attach/detach I2O gendisk structure from the
 *                      system gendisk list. The I2O block devices now appear in
 *                      /proc/partitions.
 *              Markus Lidel <Markus.Lidel@shadowconnect.com>:
 *                      Minor bugfixes for 2.6.
 */

#include <linux/module.h>
#include <linux/i2o.h>

#include <linux/mempool.h>

#include <linux/genhd.h>
#include <linux/blkdev.h>
#include <linux/hdreg.h>

#include <scsi/scsi.h>

#include "i2o_block.h"

#define OSM_NAME        "block-osm"
#define OSM_VERSION     "1.325"
#define OSM_DESCRIPTION "I2O Block Device OSM"

static struct i2o_driver i2o_block_driver;

/* global Block OSM request mempool */
static struct i2o_block_mempool i2o_blk_req_pool;

/* Block OSM class handling definition */
static struct i2o_class_id i2o_block_class_id[] = {
        {I2O_CLASS_RANDOM_BLOCK_STORAGE},
        {I2O_CLASS_END}
};

/**
 *      i2o_block_device_free - free the memory of the I2O Block device
 *      @dev: I2O Block device, which should be cleaned up
 *
 *      Frees the request queue, gendisk and the i2o_block_device structure.
 */
static void i2o_block_device_free(struct i2o_block_device *dev)
{
        blk_cleanup_queue(dev->gd->queue);

        put_disk(dev->gd);

        kfree(dev);
};

/**
 *      i2o_block_remove - remove the I2O Block device from the system again
 *      @dev: I2O Block device which should be removed
 *
 *      Remove gendisk from system and free all allocated memory.
 *
 *      Always returns 0.
 */
static int i2o_block_remove(struct device *dev)
{
        struct i2o_device *i2o_dev = to_i2o_device(dev);
        struct i2o_block_device *i2o_blk_dev = dev_get_drvdata(dev);

        osm_info("device removed (TID: %03x): %s\n", i2o_dev->lct_data.tid,
                 i2o_blk_dev->gd->disk_name);

        i2o_event_register(i2o_dev, &i2o_block_driver, 0, 0);

        del_gendisk(i2o_blk_dev->gd);

        dev_set_drvdata(dev, NULL);

        i2o_device_claim_release(i2o_dev);

        i2o_block_device_free(i2o_blk_dev);

        return 0;
};

/**
 *      i2o_block_device flush - Flush all dirty data of I2O device dev
 *      @dev: I2O device which should be flushed
 *
 *      Flushes all dirty data on device dev.
 *
 *      Returns 0 on success or negative error code on failure.
 */
static int i2o_block_device_flush(struct i2o_device *dev)
{
        struct i2o_message *msg;

        msg = i2o_msg_get_wait(dev->iop, I2O_TIMEOUT_MESSAGE_GET);
        if (IS_ERR(msg))
                return PTR_ERR(msg);

        msg->u.head[0] = cpu_to_le32(FIVE_WORD_MSG_SIZE | SGL_OFFSET_0);
        msg->u.head[1] =
            cpu_to_le32(I2O_CMD_BLOCK_CFLUSH << 24 | HOST_TID << 12 | dev->
                        lct_data.tid);
        msg->body[0] = cpu_to_le32(60 << 16);
        osm_debug("Flushing...\n");

        return i2o_msg_post_wait(dev->iop, msg, 60);
};

/**
 *      i2o_block_issue_flush - device-flush interface for block-layer
 *      @queue: the request queue of the device which should be flushed
 *      @disk: gendisk
 *      @error_sector: error offset
 *
 *      Helper function to provide flush functionality to block-layer.
 *
 *      Returns 0 on success or negative error code on failure.
 */

static int i2o_block_issue_flush(request_queue_t * queue, struct gendisk *disk,
                                 sector_t * error_sector)
{
        struct i2o_block_device *i2o_blk_dev = queue->queuedata;
        int rc = -ENODEV;

        if (likely(i2o_blk_dev))
                rc = i2o_block_device_flush(i2o_blk_dev->i2o_dev);

        return rc;
}

/**
 *      i2o_block_device_mount - Mount (load) the media of device dev
 *      @dev: I2O device which should receive the mount request
 *      @media_id: Media Identifier
 *
 *      Load a media into drive. Identifier should be set to -1, because the
 *      spec does not support any other value.
 *
 *      Returns 0 on success or negative error code on failure.
 */
static int i2o_block_device_mount(struct i2o_device *dev, u32 media_id)
{
        struct i2o_message *msg;

        msg = i2o_msg_get_wait(dev->iop, I2O_TIMEOUT_MESSAGE_GET);
        if (IS_ERR(msg))
                return PTR_ERR(msg);

        msg->u.head[0] = cpu_to_le32(FIVE_WORD_MSG_SIZE | SGL_OFFSET_0);
        msg->u.head[1] =
            cpu_to_le32(I2O_CMD_BLOCK_MMOUNT << 24 | HOST_TID << 12 | dev->
                        lct_data.tid);
        msg->body[0] = cpu_to_le32(-1);
        msg->body[1] = cpu_to_le32(0x00000000);
        osm_debug("Mounting...\n");

        return i2o_msg_post_wait(dev->iop, msg, 2);
};

/**
 *      i2o_block_device_lock - Locks the media of device dev
 *      @dev: I2O device which should receive the lock request
 *      @media_id: Media Identifier
 *
 *      Lock media of device dev to prevent removal. The media identifier
 *      should be set to -1, because the spec does not support any other value.
 *
 *      Returns 0 on success or negative error code on failure.
 */
static int i2o_block_device_lock(struct i2o_device *dev, u32 media_id)
{
        struct i2o_message *msg;

        msg = i2o_msg_get_wait(dev->iop, I2O_TIMEOUT_MESSAGE_GET);
        if (IS_ERR(msg))
                return PTR_ERR(msg);

        msg->u.head[0] = cpu_to_le32(FIVE_WORD_MSG_SIZE | SGL_OFFSET_0);
        msg->u.head[1] =
            cpu_to_le32(I2O_CMD_BLOCK_MLOCK << 24 | HOST_TID << 12 | dev->
                        lct_data.tid);
        msg->body[0] = cpu_to_le32(-1);
        osm_debug("Locking...\n");

        return i2o_msg_post_wait(dev->iop, msg, 2);
};

/**
 *      i2o_block_device_unlock - Unlocks the media of device dev
 *      @dev: I2O device which should receive the unlocked request
 *      @media_id: Media Identifier
 *
 *      Unlocks the media in device dev. The media identifier should be set to
 *      -1, because the spec does not support any other value.
 *
 *      Returns 0 on success or negative error code on failure.
 */
static int i2o_block_device_unlock(struct i2o_device *dev, u32 media_id)
{
        struct i2o_message *msg;

        msg = i2o_msg_get_wait(dev->iop, I2O_TIMEOUT_MESSAGE_GET);
        if (IS_ERR(msg))
                return PTR_ERR(msg);

        msg->u.head[0] = cpu_to_le32(FIVE_WORD_MSG_SIZE | SGL_OFFSET_0);
        msg->u.head[1] =
            cpu_to_le32(I2O_CMD_BLOCK_MUNLOCK << 24 | HOST_TID << 12 | dev->
                        lct_data.tid);
        msg->body[0] = cpu_to_le32(media_id);
        osm_debug("Unlocking...\n");

        return i2o_msg_post_wait(dev->iop, msg, 2);
};

/**
 *      i2o_block_device_power - Power management for device dev
 *      @dev: I2O device which should receive the power management request
 *      @op: Operation to send
 *
 *      Send a power management request to the device dev.
 *
 *      Returns 0 on success or negative error code on failure.
 */
static int i2o_block_device_power(struct i2o_block_device *dev, u8 op)
{
        struct i2o_device *i2o_dev = dev->i2o_dev;
        struct i2o_controller *c = i2o_dev->iop;
        struct i2o_message *msg;
        int rc;

        msg = i2o_msg_get_wait(c, I2O_TIMEOUT_MESSAGE_GET);
        if (IS_ERR(msg))
                return PTR_ERR(msg);

        msg->u.head[0] = cpu_to_le32(FOUR_WORD_MSG_SIZE | SGL_OFFSET_0);
        msg->u.head[1] =
            cpu_to_le32(I2O_CMD_BLOCK_POWER << 24 | HOST_TID << 12 | i2o_dev->
                        lct_data.tid);
        msg->body[0] = cpu_to_le32(op << 24);
        osm_debug("Power...\n");

        rc = i2o_msg_post_wait(c, msg, 60);
        if (!rc)
                dev->power = op;

        return rc;
};

/**
 *      i2o_block_request_alloc - Allocate an I2O block request struct
 *
 *      Allocates an I2O block request struct and initialize the list.
 *
 *      Returns a i2o_block_request pointer on success or negative error code
 *      on failure.
 */
static inline struct i2o_block_request *i2o_block_request_alloc(void)
{
        struct i2o_block_request *ireq;

        ireq = mempool_alloc(i2o_blk_req_pool.pool, GFP_ATOMIC);
        if (!ireq)
                return ERR_PTR(-ENOMEM);

        INIT_LIST_HEAD(&ireq->queue);

        return ireq;
};

/**
 *      i2o_block_request_free - Frees a I2O block request
 *      @ireq: I2O block request which should be freed
 *
 *      Frees the allocated memory (give it back to the request mempool).
 */
static inline void i2o_block_request_free(struct i2o_block_request *ireq)
{
        mempool_free(ireq, i2o_blk_req_pool.pool);
};

/**
 *      i2o_block_sglist_alloc - Allocate the SG list and map it
 *      @c: I2O controller to which the request belongs
 *      @ireq: I2O block request
 *      @mptr: message body pointer
 *
 *      Builds the SG list and map it to be accessable by the controller.
 *
 *      Returns 0 on failure or 1 on success.
 */
static inline int i2o_block_sglist_alloc(struct i2o_controller *c,
                                         struct i2o_block_request *ireq,
                                         u32 ** mptr)
{
        int nents;
        enum dma_data_direction direction;

        ireq->dev = &c->pdev->dev;
        nents = blk_rq_map_sg(ireq->req->q, ireq->req, ireq->sg_table);

        if (rq_data_dir(ireq->req) == READ)
                direction = PCI_DMA_FROMDEVICE;
        else
                direction = PCI_DMA_TODEVICE;

        ireq->sg_nents = nents;

        return i2o_dma_map_sg(c, ireq->sg_table, nents, direction, mptr);
};

/**
 *      i2o_block_sglist_free - Frees the SG list
 *      @ireq: I2O block request from which the SG should be freed
 *
 *      Frees the SG list from the I2O block request.
 */
static inline void i2o_block_sglist_free(struct i2o_block_request *ireq)
{
        enum dma_data_direction direction;

        if (rq_data_dir(ireq->req) == READ)
                direction = PCI_DMA_FROMDEVICE;
        else
                direction = PCI_DMA_TODEVICE;

        dma_unmap_sg(ireq->dev, ireq->sg_table, ireq->sg_nents, direction);
};

/**
 *      i2o_block_prep_req_fn - Allocates I2O block device specific struct
 *      @q: request queue for the request
 *      @req: the request to prepare
 *
 *      Allocate the necessary i2o_block_request struct and connect it to
 *      the request. This is needed that we not loose the SG list later on.
 *
 *      Returns BLKPREP_OK on success or BLKPREP_DEFER on failure.
 */
static int i2o_block_prep_req_fn(struct request_queue *q, struct request *req)
{
        struct i2o_block_device *i2o_blk_dev = q->queuedata;
        struct i2o_block_request *ireq;

        if (unlikely(!i2o_blk_dev)) {
                osm_err("block device already removed\n");
                return BLKPREP_KILL;
        }

        /* connect the i2o_block_request to the request */
        if (!req->special) {
                ireq = i2o_block_request_alloc();
                if (unlikely(IS_ERR(ireq))) {
                        osm_debug("unable to allocate i2o_block_request!\n");
                        return BLKPREP_DEFER;
                }

                ireq->i2o_blk_dev = i2o_blk_dev;
                req->special = ireq;
                ireq->req = req;
        }
        /* do not come back here */
        req->cmd_flags |= REQ_DONTPREP;

        return BLKPREP_OK;
};

/**
 *      i2o_block_delayed_request_fn - delayed request queue function
 *      @work: the delayed request with the queue to start
 *
 *      If the request queue is stopped for a disk, and there is no open
 *      request, a new event is created, which calls this function to start
 *      the queue after I2O_BLOCK_REQUEST_TIME. Otherwise the queue will never
 *      be started again.
 */
static void i2o_block_delayed_request_fn(struct work_struct *work)
{
        struct i2o_block_delayed_request *dreq =
                container_of(work, struct i2o_block_delayed_request,
                             work.work);
        struct request_queue *q = dreq->queue;
        unsigned long flags;

        spin_lock_irqsave(q->queue_lock, flags);
        blk_start_queue(q);
        spin_unlock_irqrestore(q->queue_lock, flags);
        kfree(dreq);
};

/**
 *      i2o_block_end_request - Post-processing of completed commands
 *      @req: request which should be completed
 *      @uptodate: 1 for success, 0 for I/O error, < 0 for specific error
 *      @nr_bytes: number of bytes to complete
 *
 *      Mark the request as complete. The lock must not be held when entering.
 *
 */
static void i2o_block_end_request(struct request *req, int uptodate,
                                  int nr_bytes)
{
        struct i2o_block_request *ireq = req->special;
        struct i2o_block_device *dev = ireq->i2o_blk_dev;
        request_queue_t *q = req->q;
        unsigned long flags;

        if (end_that_request_chunk(req, uptodate, nr_bytes)) {
                int leftover = (req->hard_nr_sectors << KERNEL_SECTOR_SHIFT);

                if (blk_pc_request(req))
                        leftover = req->data_len;

                if (end_io_error(uptodate))
                        end_that_request_chunk(req, 0, leftover);
        }

        add_disk_randomness(req->rq_disk);

        spin_lock_irqsave(q->queue_lock, flags);

        end_that_request_last(req, uptodate);

        if (likely(dev)) {
                dev->open_queue_depth--;
                list_del(&ireq->queue);
        }

        blk_start_queue(q);

        spin_unlock_irqrestore(q->queue_lock, flags);

        i2o_block_sglist_free(ireq);
        i2o_block_request_free(ireq);
};

/**
 *      i2o_block_reply - Block OSM reply handler.
 *      @c: I2O controller from which the message arrives
 *      @m: message id of reply
 *      @msg: the actual I2O message reply
 *
 *      This function gets all the message replies.
 *
 */
static int i2o_block_reply(struct i2o_controller *c, u32 m,
                           struct i2o_message *msg)
{
        struct request *req;
        int uptodate = 1;

        req = i2o_cntxt_list_get(c, le32_to_cpu(msg->u.s.tcntxt));
        if (unlikely(!req)) {
                osm_err("NULL reply received!\n");
                return -1;
        }

        /*
         *      Lets see what is cooking. We stuffed the
         *      request in the context.
         */

        if ((le32_to_cpu(msg->body[0]) >> 24) != 0) {
                u32 status = le32_to_cpu(msg->body[0]);
                /*
                 *      Device not ready means two things. One is that the
                 *      the thing went offline (but not a removal media)
                 *
                 *      The second is that you have a SuperTrak 100 and the
                 *      firmware got constipated. Unlike standard i2o card
                 *      setups the supertrak returns an error rather than
                 *      blocking for the timeout in these cases.
                 *
                 *      Don't stick a supertrak100 into cache aggressive modes
                 */

                osm_err("TID %03x error status: 0x%02x, detailed status: "
                        "0x%04x\n", (le32_to_cpu(msg->u.head[1]) >> 12 & 0xfff),
                        status >> 24, status & 0xffff);

                req->errors++;

                uptodate = 0;
        }

        i2o_block_end_request(req, uptodate, le32_to_cpu(msg->body[1]));

        return 1;
};

static void i2o_block_event(struct work_struct *work)
{
        struct i2o_event *evt = container_of(work, struct i2o_event, work);
        osm_debug("event received\n");
        kfree(evt);
};

/*
 *      SCSI-CAM for ioctl geometry mapping
 *      Duplicated with SCSI - this should be moved into somewhere common
 *      perhaps genhd ?
 *
 * LBA -> CHS mapping table taken from:
 *
 * "Incorporating the I2O Architecture into BIOS for Intel Architecture
 *  Platforms"
 *
 * This is an I2O document that is only available to I2O members,
 * not developers.
 *
 * From my understanding, this is how all the I2O cards do this
 *
 * Disk Size      | Sectors | Heads | Cylinders
 * ---------------+---------+-------+-------------------
 * 1 < X <= 528M  | 63      | 16    | X/(63 * 16 * 512)
 * 528M < X <= 1G | 63      | 32    | X/(63 * 32 * 512)
 * 1 < X <528M    | 63      | 16    | X/(63 * 16 * 512)
 * 1 < X <528M    | 63      | 16    | X/(63 * 16 * 512)
 *
 */
#define BLOCK_SIZE_528M         1081344
#define BLOCK_SIZE_1G           2097152
#define BLOCK_SIZE_21G          4403200
#define BLOCK_SIZE_42G          8806400
#define BLOCK_SIZE_84G          17612800

static void i2o_block_biosparam(unsigned long capacity, unsigned short *cyls,
                                unsigned char *hds, unsigned char *secs)
{
        unsigned long heads, sectors, cylinders;

        sectors = 63L;          /* Maximize sectors per track */
        if (capacity <= BLOCK_SIZE_528M)
                heads = 16;
        else if (capacity <= BLOCK_SIZE_1G)
                heads = 32;
        else if (capacity <= BLOCK_SIZE_21G)
                heads = 64;
        else if (capacity <= BLOCK_SIZE_42G)
                heads = 128;
        else
                heads = 255;

        cylinders = (unsigned long)capacity / (heads * sectors);

        *cyls = (unsigned short)cylinders;      /* Stuff return values */
        *secs = (unsigned char)sectors;
        *hds = (unsigned char)heads;
}

/**
 *      i2o_block_open - Open the block device
 *      @inode: inode for block device being opened
 *      @file: file to open
 *
 *      Power up the device, mount and lock the media. This function is called,
 *      if the block device is opened for access.
 *
 *      Returns 0 on success or negative error code on failure.
 */
static int i2o_block_open(struct inode *inode, struct file *file)
{
        struct i2o_block_device *dev = inode->i_bdev->bd_disk->private_data;

        if (!dev->i2o_dev)
                return -ENODEV;

        if (dev->power > 0x1f)
                i2o_block_device_power(dev, 0x02);

        i2o_block_device_mount(dev->i2o_dev, -1);

        i2o_block_device_lock(dev->i2o_dev, -1);

        osm_debug("Ready.\n");

        return 0;
};

/**
 *      i2o_block_release - Release the I2O block device
 *      @inode: inode for block device being released
 *      @file: file to close
 *
 *      Unlock and unmount the media, and power down the device. Gets called if
 *      the block device is closed.
 *
 *      Returns 0 on success or negative error code on failure.
 */
static int i2o_block_release(struct inode *inode, struct file *file)
{
        struct gendisk *disk = inode->i_bdev->bd_disk;
        struct i2o_block_device *dev = disk->private_data;
        u8 operation;

        /*
         * This is to deail with the case of an application
         * opening a device and then the device dissapears while
         * it's in use, and then the application tries to release
         * it.  ex: Unmounting a deleted RAID volume at reboot.
         * If we send messages, it will just cause FAILs since
         * the TID no longer exists.
         */
        if (!dev->i2o_dev)
                return 0;

        i2o_block_device_flush(dev->i2o_dev);

        i2o_block_device_unlock(dev->i2o_dev, -1);

        if (dev->flags & (1 << 3 | 1 << 4))     /* Removable */
                operation = 0x21;
        else
                operation = 0x24;

        i2o_block_device_power(dev, operation);

        return 0;
}

static int i2o_block_getgeo(struct block_device *bdev, struct hd_geometry *geo)
{
        i2o_block_biosparam(get_capacity(bdev->bd_disk),
                            &geo->cylinders, &geo->heads, &geo->sectors);
        return 0;
}

/**
 *      i2o_block_ioctl - Issue device specific ioctl calls.
 *      @inode: inode for block device ioctl
 *      @file: file for ioctl
 *      @cmd: ioctl command
 *      @arg: arg
 *
 *      Handles ioctl request for the block device.
 *
 *      Return 0 on success or negative error on failure.
 */
static int i2o_block_ioctl(struct inode *inode, struct file *file,
                           unsigned int cmd, unsigned long arg)
{
        struct gendisk *disk = inode->i_bdev->bd_disk;
        struct i2o_block_device *dev = disk->private_data;

        /* Anyone capable of this syscall can do *real bad* things */

        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;

        switch (cmd) {
        case BLKI2OGRSTRAT:
                return put_user(dev->rcache, (int __user *)arg);
        case BLKI2OGWSTRAT:
                return put_user(dev->wcache, (int __user *)arg);
        case BLKI2OSRSTRAT:
                if (arg < 0 || arg > CACHE_SMARTFETCH)
                        return -EINVAL;
                dev->rcache = arg;
                break;
        case BLKI2OSWSTRAT:
                if (arg != 0
                    && (arg < CACHE_WRITETHROUGH || arg > CACHE_SMARTBACK))
                        return -EINVAL;
                dev->wcache = arg;
                break;
        }
        return -ENOTTY;
};

/**
 *      i2o_block_media_changed - Have we seen a media change?
 *      @disk: gendisk which should be verified
 *
 *      Verifies if the media has changed.
 *
 *      Returns 1 if the media was changed or 0 otherwise.
 */
static int i2o_block_media_changed(struct gendisk *disk)
{
        struct i2o_block_device *p = disk->private_data;

        if (p->media_change_flag) {
                p->media_change_flag = 0;
                return 1;
        }
        return 0;
}

/**
 *      i2o_block_transfer - Transfer a request to/from the I2O controller
 *      @req: the request which should be transfered
 *
 *      This function converts the request into a I2O message. The necessary
 *      DMA buffers are allocated and after everything is setup post the message
 *      to the I2O controller. No cleanup is done by this function. It is done
 *      on the interrupt side when the reply arrives.
 *
 *      Return 0 on success or negative error code on failure.
 */
static int i2o_block_transfer(struct request *req)
{
        struct i2o_block_device *dev = req->rq_disk->private_data;
        struct i2o_controller *c;
        int tid = dev->i2o_dev->lct_data.tid;
        struct i2o_message *msg;
        u32 *mptr;
        struct i2o_block_request *ireq = req->special;
        u32 tcntxt;
        u32 sgl_offset = SGL_OFFSET_8;
        u32 ctl_flags = 0x00000000;
        int rc;
        u32 cmd;

        if (unlikely(!dev->i2o_dev)) {
                osm_err("transfer to removed drive\n");
                rc = -ENODEV;
                goto exit;
        }

        c = dev->i2o_dev->iop;

        msg = i2o_msg_get(c);
        if (IS_ERR(msg)) {
                rc = PTR_ERR(msg);
                goto exit;
        }

        tcntxt = i2o_cntxt_list_add(c, req);
        if (!tcntxt) {
                rc = -ENOMEM;
                goto nop_msg;
        }

        msg->u.s.icntxt = cpu_to_le32(i2o_block_driver.context);
        msg->u.s.tcntxt = cpu_to_le32(tcntxt);

        mptr = &msg->body[0];

        if (rq_data_dir(req) == READ) {
                cmd = I2O_CMD_BLOCK_READ << 24;

                switch (dev->rcache) {
                case CACHE_PREFETCH:
                        ctl_flags = 0x201F0008;
                        break;

                case CACHE_SMARTFETCH:
                        if (req->nr_sectors > 16)
                                ctl_flags = 0x201F0008;
                        else
                                ctl_flags = 0x001F0000;
                        break;

                default:
                        break;
                }
        } else {
                cmd = I2O_CMD_BLOCK_WRITE << 24;

                switch (dev->wcache) {
                case CACHE_WRITETHROUGH:
                        ctl_flags = 0x001F0008;
                        break;
                case CACHE_WRITEBACK:
                        ctl_flags = 0x001F0010;
                        break;
                case CACHE_SMARTBACK:
                        if (req->nr_sectors > 16)
                                ctl_flags = 0x001F0004;
                        else
                                ctl_flags = 0x001F0010;
                        break;
                case CACHE_SMARTTHROUGH:
                        if (req->nr_sectors > 16)
                                ctl_flags = 0x001F0004;
                        else
                                ctl_flags = 0x001F0010;
                default:
                        break;
                }
        }

#ifdef CONFIG_I2O_EXT_ADAPTEC
        if (c->adaptec) {
                u8 cmd[10];
                u32 scsi_flags;
                u16 hwsec = queue_hardsect_size(req->q) >> KERNEL_SECTOR_SHIFT;

                memset(cmd, 0, 10);

                sgl_offset = SGL_OFFSET_12;

                msg->u.head[1] =
                    cpu_to_le32(I2O_CMD_PRIVATE << 24 | HOST_TID << 12 | tid);

                *mptr++ = cpu_to_le32(I2O_VENDOR_DPT << 16 | I2O_CMD_SCSI_EXEC);
                *mptr++ = cpu_to_le32(tid);

                /*
                 * ENABLE_DISCONNECT
                 * SIMPLE_TAG
                 * RETURN_SENSE_DATA_IN_REPLY_MESSAGE_FRAME
                 */
                if (rq_data_dir(req) == READ) {
                        cmd[0] = READ_10;
                        scsi_flags = 0x60a0000a;
                } else {
                        cmd[0] = WRITE_10;
                        scsi_flags = 0xa0a0000a;
                }

                *mptr++ = cpu_to_le32(scsi_flags);

                *((u32 *) & cmd[2]) = cpu_to_be32(req->sector * hwsec);
                *((u16 *) & cmd[7]) = cpu_to_be16(req->nr_sectors * hwsec);

                memcpy(mptr, cmd, 10);
                mptr += 4;
                *mptr++ = cpu_to_le32(req->nr_sectors << KERNEL_SECTOR_SHIFT);
        } else
#endif
        {
                msg->u.head[1] = cpu_to_le32(cmd | HOST_TID << 12 | tid);
                *mptr++ = cpu_to_le32(ctl_flags);
                *mptr++ = cpu_to_le32(req->nr_sectors << KERNEL_SECTOR_SHIFT);
                *mptr++ =
                    cpu_to_le32((u32) (req->sector << KERNEL_SECTOR_SHIFT));
                *mptr++ =
                    cpu_to_le32(req->sector >> (32 - KERNEL_SECTOR_SHIFT));
        }

        if (!i2o_block_sglist_alloc(c, ireq, &mptr)) {
                rc = -ENOMEM;
                goto context_remove;
        }

        msg->u.head[0] =
            cpu_to_le32(I2O_MESSAGE_SIZE(mptr - &msg->u.head[0]) | sgl_offset);

        list_add_tail(&ireq->queue, &dev->open_queue);
        dev->open_queue_depth++;

        i2o_msg_post(c, msg);

        return 0;

      context_remove:
        i2o_cntxt_list_remove(c, req);

      nop_msg:
        i2o_msg_nop(c, msg);

      exit:
        return rc;
};

/**
 *      i2o_block_request_fn - request queue handling function
 *      @q: request queue from which the request could be fetched
 *
 *      Takes the next request from the queue, transfers it and if no error
 *      occurs dequeue it from the queue. On arrival of the reply the message
 *      will be processed further. If an error occurs requeue the request.
 */
static void i2o_block_request_fn(struct request_queue *q)
{
        struct request *req;

        while (!blk_queue_plugged(q)) {
                req = elv_next_request(q);
                if (!req)
                        break;

                if (blk_fs_request(req)) {
                        struct i2o_block_delayed_request *dreq;
                        struct i2o_block_request *ireq = req->special;
                        unsigned int queue_depth;

                        queue_depth = ireq->i2o_blk_dev->open_queue_depth;

                        if (queue_depth < I2O_BLOCK_MAX_OPEN_REQUESTS) {
                                if (!i2o_block_transfer(req)) {
                                        blkdev_dequeue_request(req);
                                        continue;
                                } else
                                        osm_info("transfer error\n");
                        }

                        if (queue_depth)
                                break;

                        /* stop the queue and retry later */
                        dreq = kmalloc(sizeof(*dreq), GFP_ATOMIC);
                        if (!dreq)
                                continue;

                        dreq->queue = q;
                        INIT_DELAYED_WORK(&dreq->work,
                                          i2o_block_delayed_request_fn);

                        if (!queue_delayed_work(i2o_block_driver.event_queue,
                                                &dreq->work,
                                                I2O_BLOCK_RETRY_TIME))
                                kfree(dreq);
                        else {
                                blk_stop_queue(q);
                                break;
                        }
                } else
                        end_request(req, 0);
        }
};

/* I2O Block device operations definition */
static struct block_device_operations i2o_block_fops = {
        .owner = THIS_MODULE,
        .open = i2o_block_open,
        .release = i2o_block_release,
        .ioctl = i2o_block_ioctl,
        .getgeo = i2o_block_getgeo,
        .media_changed = i2o_block_media_changed
};

/**
 *      i2o_block_device_alloc - Allocate memory for a I2O Block device
 *
 *      Allocate memory for the i2o_block_device struct, gendisk and request
 *      queue and initialize them as far as no additional information is needed.
 *
 *      Returns a pointer to the allocated I2O Block device on succes or a
 *      negative error code on failure.
 */
static struct i2o_block_device *i2o_block_device_alloc(void)
{
        struct i2o_block_device *dev;
        struct gendisk *gd;
        struct request_queue *queue;
        int rc;

        dev = kzalloc(sizeof(*dev), GFP_KERNEL);
        if (!dev) {
                osm_err("Insufficient memory to allocate I2O Block disk.\n");
                rc = -ENOMEM;
                goto exit;
        }

        INIT_LIST_HEAD(&dev->open_queue);
        spin_lock_init(&dev->lock);
        dev->rcache = CACHE_PREFETCH;
        dev->wcache = CACHE_WRITEBACK;

        /* allocate a gendisk with 16 partitions */
        gd = alloc_disk(16);
        if (!gd) {
                osm_err("Insufficient memory to allocate gendisk.\n");
                rc = -ENOMEM;
                goto cleanup_dev;
        }

        /* initialize the request queue */
        queue = blk_init_queue(i2o_block_request_fn, &dev->lock);
        if (!queue) {
                osm_err("Insufficient memory to allocate request queue.\n");
                rc = -ENOMEM;
                goto cleanup_queue;
        }

        blk_queue_prep_rq(queue, i2o_block_prep_req_fn);
        blk_queue_issue_flush_fn(queue, i2o_block_issue_flush);

        gd->major = I2O_MAJOR;
        gd->queue = queue;
        gd->fops = &i2o_block_fops;
        gd->private_data = dev;

        dev->gd = gd;

        return dev;

      cleanup_queue:
        put_disk(gd);

      cleanup_dev:
        kfree(dev);

      exit:
        return ERR_PTR(rc);
};

/**
 *      i2o_block_probe - verify if dev is a I2O Block device and install it
 *      @dev: device to verify if it is a I2O Block device
 *
 *      We only verify if the user_tid of the device is 0xfff and then install
 *      the device. Otherwise it is used by some other device (e. g. RAID).
 *
 *      Returns 0 on success or negative error code on failure.
 */
static int i2o_block_probe(struct device *dev)
{
        struct i2o_device *i2o_dev = to_i2o_device(dev);
        struct i2o_controller *c = i2o_dev->iop;
        struct i2o_block_device *i2o_blk_dev;
        struct gendisk *gd;
        struct request_queue *queue;
        static int unit = 0;
        int rc;
        u64 size;
        u32 blocksize;
        u16 body_size = 4;
        u16 power;
        unsigned short max_sectors;

#ifdef CONFIG_I2O_EXT_ADAPTEC
        if (c->adaptec)
                body_size = 8;
#endif

        if (c->limit_sectors)
                max_sectors = I2O_MAX_SECTORS_LIMITED;
        else
                max_sectors = I2O_MAX_SECTORS;

        /* skip devices which are used by IOP */
        if (i2o_dev->lct_data.user_tid != 0xfff) {
                osm_debug("skipping used device %03x\n", i2o_dev->lct_data.tid);
                return -ENODEV;
        }

        if (i2o_device_claim(i2o_dev)) {
                osm_warn("Unable to claim device. Installation aborted\n");
                rc = -EFAULT;
                goto exit;
        }

        i2o_blk_dev = i2o_block_device_alloc();
        if (IS_ERR(i2o_blk_dev)) {
                osm_err("could not alloc a new I2O block device");
                rc = PTR_ERR(i2o_blk_dev);
                goto claim_release;
        }

        i2o_blk_dev->i2o_dev = i2o_dev;
        dev_set_drvdata(dev, i2o_blk_dev);

        /* setup gendisk */
        gd = i2o_blk_dev->gd;
        gd->first_minor = unit << 4;
        sprintf(gd->disk_name, "i2o/hd%c", 'a' + unit);
        gd->driverfs_dev = &i2o_dev->device;

        /* setup request queue */
        queue = gd->queue;
        queue->queuedata = i2o_blk_dev;

        blk_queue_max_phys_segments(queue, I2O_MAX_PHYS_SEGMENTS);
        blk_queue_max_sectors(queue, max_sectors);
        blk_queue_max_hw_segments(queue, i2o_sg_tablesize(c, body_size));

        osm_debug("max sectors = %d\n", queue->max_phys_segments);
        osm_debug("phys segments = %d\n", queue->max_sectors);
        osm_debug("max hw segments = %d\n", queue->max_hw_segments);

        /*
         *      Ask for the current media data. If that isn't supported
         *      then we ask for the device capacity data
         */
        if (!i2o_parm_field_get(i2o_dev, 0x0004, 1, &blocksize, 4) ||
            !i2o_parm_field_get(i2o_dev, 0x0000, 3, &blocksize, 4)) {
                blk_queue_hardsect_size(queue, le32_to_cpu(blocksize));
        } else
                osm_warn("unable to get blocksize of %s\n", gd->disk_name);

        if (!i2o_parm_field_get(i2o_dev, 0x0004, 0, &size, 8) ||
            !i2o_parm_field_get(i2o_dev, 0x0000, 4, &size, 8)) {
                set_capacity(gd, le64_to_cpu(size) >> KERNEL_SECTOR_SHIFT);
        } else
                osm_warn("could not get size of %s\n", gd->disk_name);

        if (!i2o_parm_field_get(i2o_dev, 0x0000, 2, &power, 2))
                i2o_blk_dev->power = power;

        i2o_event_register(i2o_dev, &i2o_block_driver, 0, 0xffffffff);

        add_disk(gd);

        unit++;

        osm_info("device added (TID: %03x): %s\n", i2o_dev->lct_data.tid,
                 i2o_blk_dev->gd->disk_name);

        return 0;

      claim_release:
        i2o_device_claim_release(i2o_dev);

      exit:
        return rc;
};

/* Block OSM driver struct */
static struct i2o_driver i2o_block_driver = {
        .name = OSM_NAME,
        .event = i2o_block_event,
        .reply = i2o_block_reply,
        .classes = i2o_block_class_id,
        .driver = {
                   .probe = i2o_block_probe,
                   .remove = i2o_block_remove,
                   },
};

/**
 *      i2o_block_init - Block OSM initialization function
 *
 *      Allocate the slab and mempool for request structs, registers i2o_block
 *      block device and finally register the Block OSM in the I2O core.
 *
 *      Returns 0 on success or negative error code on failure.
 */
static int __init i2o_block_init(void)
{
        int rc;
        int size;

        printk(KERN_INFO OSM_DESCRIPTION " v" OSM_VERSION "\n");

        /* Allocate request mempool and slab */
        size = sizeof(struct i2o_block_request);
        i2o_blk_req_pool.slab = kmem_cache_create("i2o_block_req", size, 0,
                                                  SLAB_HWCACHE_ALIGN, NULL);
        if (!i2o_blk_req_pool.slab) {
                osm_err("can't init request slab\n");
                rc = -ENOMEM;
                goto exit;
        }

        i2o_blk_req_pool.pool =
                mempool_create_slab_pool(I2O_BLOCK_REQ_MEMPOOL_SIZE,
                                         i2o_blk_req_pool.slab);
        if (!i2o_blk_req_pool.pool) {
                osm_err("can't init request mempool\n");
                rc = -ENOMEM;
                goto free_slab;
        }

        /* Register the block device interfaces */
        rc = register_blkdev(I2O_MAJOR, "i2o_block");
        if (rc) {
                osm_err("unable to register block device\n");
                goto free_mempool;
        }
#ifdef MODULE
        osm_info("registered device at major %d\n", I2O_MAJOR);
#endif

        /* Register Block OSM into I2O core */
        rc = i2o_driver_register(&i2o_block_driver);
        if (rc) {
                osm_err("Could not register Block driver\n");
                goto unregister_blkdev;
        }

        return 0;

      unregister_blkdev:
        unregister_blkdev(I2O_MAJOR, "i2o_block");

      free_mempool:
        mempool_destroy(i2o_blk_req_pool.pool);

      free_slab:
        kmem_cache_destroy(i2o_blk_req_pool.slab);

      exit:
        return rc;
};

/**
 *      i2o_block_exit - Block OSM exit function
 *
 *      Unregisters Block OSM from I2O core, unregisters i2o_block block device
 *      and frees the mempool and slab.
 */
static void __exit i2o_block_exit(void)
{
        /* Unregister I2O Block OSM from I2O core */
        i2o_driver_unregister(&i2o_block_driver);

        /* Unregister block device */
        unregister_blkdev(I2O_MAJOR, "i2o_block");

        /* Free request mempool and slab */
        mempool_destroy(i2o_blk_req_pool.pool);
        kmem_cache_destroy(i2o_blk_req_pool.slab);
};

MODULE_AUTHOR("Red Hat");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION(OSM_DESCRIPTION);
MODULE_VERSION(OSM_VERSION);

module_init(i2o_block_init);
module_exit(i2o_block_exit);