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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_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);
      sg_init_table(ireq->sg_table, I2O_MAX_PHYS_SEGMENTS);

      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;
      struct request_queue *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;
      u32 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);

      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_sectors);
      osm_debug("phys segments = %d\n", queue->max_phys_segments);
      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);

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